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Ouyang W, Wientjes E, van der Putten PEL, Caracciolo L, Zhao R, Agho C, Chiurazzi MJ, Bongers M, Struik PC, van Amerongen H, Yin X. Roles for leakiness and O 2 evolution in explaining lower-than-theoretical quantum yields of photosynthesis in the PEP-CK subtype of C 4 plants. THE NEW PHYTOLOGIST 2024; 242:431-443. [PMID: 38406986 DOI: 10.1111/nph.19614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 01/30/2024] [Indexed: 02/27/2024]
Abstract
Theoretically, the PEP-CK C4 subtype has a higher quantum yield of CO2 assimilation (Φ CO 2 ) than NADP-ME or NAD-ME subtypes because ATP required for operating the CO2-concentrating mechanism is believed to mostly come from the mitochondrial electron transport chain (mETC). However, reportedΦ CO 2 is not higher in PEP-CK than in the other subtypes. We hypothesise, more photorespiration, associated with higher leakiness and O2 evolution in bundle-sheath (BS) cells, cancels out energetic advantages in PEP-CK species. Nine species (two to four species per subtype) were evaluated by gas exchange, chlorophyll fluorescence, and two-photon microscopy to estimate the BS conductance (gbs) and leakiness using a biochemical model. Average gbs estimates were 2.9, 4.8, and 5.0 mmol m-2 s-1 bar-1, and leakiness values were 0.129, 0.179, and 0.180, in NADP-ME, NAD-ME, and PEP-CK species, respectively. The BS CO2 level was somewhat higher, O2 level was marginally lower, and thus, photorespiratory loss was slightly lower, in NADP-ME than in NAD-ME and PEP-CK species. Differences in these parameters existed among species within a subtype, and gbs was co-determined by biochemical decarboxylating sites and anatomical characteristics. Our hypothesis and results partially explain variations in observedΦ CO 2 , but suggest that PEP-CK species probably use less ATP from mETC than classically defined PEP-CK mechanisms.
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Affiliation(s)
- Wenjing Ouyang
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
- School of Agriculture, Yunnan University, Kunming, 650504, Yunnan, China
| | - Emilie Wientjes
- Laboratory of Biophysics, Wageningen University & Research, PO Box 8128, 6700 ET, Wageningen, the Netherlands
| | - Peter E L van der Putten
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Ludovico Caracciolo
- Laboratory of Biophysics, Wageningen University & Research, PO Box 8128, 6700 ET, Wageningen, the Netherlands
| | - Ruixuan Zhao
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
- School of Agriculture, Yunnan University, Kunming, 650504, Yunnan, China
| | - Collins Agho
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Maurizio Junior Chiurazzi
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Marius Bongers
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
| | - Herbert van Amerongen
- Laboratory of Biophysics, Wageningen University & Research, PO Box 8128, 6700 ET, Wageningen, the Netherlands
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Wageningen University & Research, PO Box 430, 6700 AK, Wageningen, the Netherlands
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Ubierna N, Holloway-Phillips MM, Wingate L, Ogée J, Busch FA, Farquhar GD. Using Carbon Stable Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2024; 2790:163-211. [PMID: 38649572 DOI: 10.1007/978-1-0716-3790-6_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, laser absorption spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets at lower cost and with unprecedented temporal resolution. More data and accompanying knowledge have permitted refinement of 13C discrimination model equations, but often at the expense of increased model complexity and difficult parametrization. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations available to researchers. We update our previous 2018 version of this chapter by including recently improved descriptions of (photo)respiratory processes and associated fractionations. We discuss the capabilities and limitations of the diverse 13C discrimination model equations and provide guidance for selecting the model complexity needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Meisha-Marika Holloway-Phillips
- Research Unit of Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Birmendsorf, Switzerland
| | - Lisa Wingate
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Jérôme Ogée
- Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Unité Mixte de Recherche (UMR)1391 ISPA, Villenave D'Ornon, France
| | - Florian A Busch
- School of Biosciences and The Birmingham Institute of Forest Research, University of Birmingham, Birmingham, UK
| | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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Zhou H, Akçay E, Helliker B. Optimal coordination and reorganization of photosynthetic properties in C 4 grasses. PLANT, CELL & ENVIRONMENT 2023; 46:796-811. [PMID: 36478594 DOI: 10.1111/pce.14506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 06/17/2023]
Abstract
Each of >20 independent evolutions of C4 photosynthesis in grasses required reorganization of the Calvin-Benson-cycle (CB-cycle) within the leaf, along with coordination of C4 -cycle enzymes with the CB-cycle to maximize CO2 assimilation. Considering the vast amount of time over which C4 evolved, we hypothesized (i) trait divergences exist within and across lineages with both C4 and closely related C3 grasses, (ii) trends in traits after C4 evolution yield the optimization of C4 through time, and (iii) the presence/absence of trends in coordination between the CB-cycle and C4 -cycle provides information on the strength of selection. To address these hypotheses, we used a combination of optimality modelling, physiological measurements and phylogenetic-comparative-analysis. Photosynthesis was optimized after the evolution of C4 causing diversification in maximal assimilation, electron transport, Rubisco carboxylation, phosphoenolpyruvate carboxylase and chlorophyll within C4 lineages. Both theory and measurements indicated a higher light-reaction to CB-cycle ratio (Jatpmax /Vcmax ) in C4 than C3 . There were no evolutionary trends with photosynthetic coordination between the CB-cycle, light reactions and the C4 -cycle, suggesting strong initial selection for coordination. The coordination of CB-C4 -cycles (Vpmax /Vcmax ) was optimal for CO2 of 200 ppm, not to current conditions. Our model indicated that a higher than optimal Vpmax /Vcmax affects assimilation minimally, thus lessening recent selection to decrease Vpmax /Vcmax .
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Affiliation(s)
- Haoran Zhou
- School of Earth System Science, Institute of Surface-Earth System Science, Tianjin University, Tianjin, China
- School of the Environment, Yale University, New Haven, Connecticut, USA
| | - Erol Akçay
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brent Helliker
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Wang Y, Stutz SS, Bernacchi CJ, Boyd RA, Ort DR, Long SP. Increased bundle-sheath leakiness of CO 2 during photosynthetic induction shows a lack of coordination between the C 4 and C 3 cycles. THE NEW PHYTOLOGIST 2022; 236:1661-1675. [PMID: 36098668 PMCID: PMC9827928 DOI: 10.1111/nph.18485] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 08/25/2022] [Indexed: 05/31/2023]
Abstract
Use of a complete dynamic model of NADP-malic enzyme C4 photosynthesis indicated that, during transitions from dark or shade to high light, induction of the C4 pathway was more rapid than that of C3 , resulting in a predicted transient increase in bundle-sheath CO2 leakiness (ϕ). Previously, ϕ has been measured at steady state; here we developed a new method, coupling a tunable diode laser absorption spectroscope with a gas-exchange system to track ϕ in sorghum and maize through the nonsteady-state condition of photosynthetic induction. In both species, ϕ showed a transient increase to > 0.35 before declining to a steady state of 0.2 by 1500 s after illumination. Average ϕ was 60% higher than at steady state over the first 600 s of induction and 30% higher over the first 1500 s. The transient increase in ϕ, which was consistent with model prediction, indicated that capacity to assimilate CO2 into the C3 cycle in the bundle sheath failed to keep pace with the rate of dicarboxylate delivery by the C4 cycle. Because nonsteady-state light conditions are the norm in field canopies, the results suggest that ϕ in these major crops in the field is significantly higher and energy conversion efficiency lower than previous measured values under steady-state conditions.
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Affiliation(s)
- Yu Wang
- The Carl R. Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐Champaign1206 W Gregory DrUrbanaIL61801USA
- DOE Center for Advanced Bioenergy and Bioproducts InnovationUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
| | - Samantha S. Stutz
- The Carl R. Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐Champaign1206 W Gregory DrUrbanaIL61801USA
| | - Carl J. Bernacchi
- DOE Center for Advanced Bioenergy and Bioproducts InnovationUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
- USDA‐ARS Global Change and Photosynthesis Research UnitUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
- Departments of Plant Biology and Crop SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
| | - Ryan A. Boyd
- The Carl R. Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐Champaign1206 W Gregory DrUrbanaIL61801USA
| | - Donald R. Ort
- The Carl R. Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐Champaign1206 W Gregory DrUrbanaIL61801USA
- DOE Center for Advanced Bioenergy and Bioproducts InnovationUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
- Departments of Plant Biology and Crop SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
| | - Stephen P. Long
- The Carl R. Woese Institute for Genomic BiologyUniversity of Illinois Urbana‐Champaign1206 W Gregory DrUrbanaIL61801USA
- DOE Center for Advanced Bioenergy and Bioproducts InnovationUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
- Departments of Plant Biology and Crop SciencesUniversity of Illinois at Urbana‐ChampaignUrbanaIL61801USA
- Lancaster Environment CentreLancaster UniversityLancasterLA1 4YQUK
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Pathare VS, DiMario RJ, Koteyeva N, Cousins AB. Mesophyll conductance response to short-term changes in pCO 2 is related to leaf anatomy and biochemistry in diverse C 4 grasses. THE NEW PHYTOLOGIST 2022; 236:1281-1295. [PMID: 35959528 PMCID: PMC9825963 DOI: 10.1111/nph.18427] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Mesophyll CO2 conductance (gm ) in C3 species responds to short-term (minutes) changes in environment potentially due to changes in leaf anatomical and biochemical properties and measurement artefacts. Compared with C3 species, there is less information on gm responses to short-term changes in environmental conditions such as partial pressure of CO2 (pCO2 ) across diverse C4 species and the potential determinants of these responses. Using 16 C4 grasses we investigated the response of gm to short-term changes in pCO2 and its relationship with leaf anatomy and biochemistry. In general, gm increased as pCO2 decreased (statistically significant increase in 12 species), with percentage increases in gm ranging from +13% to +250%. Greater increase in gm at low pCO2 was observed in species exhibiting relatively thinner mesophyll cell walls along with greater mesophyll surface area exposed to intercellular air spaces, leaf N, photosynthetic capacity and activities of phosphoenolpyruvate carboxylase and Rubisco. Species with greater CO2 responses of gm were also able to maintain their leaf water-use efficiencies (TEi ) under low CO2 . Our study advances understanding of CO2 response of gm in diverse C4 species, identifies the key leaf traits related to this response and has implications for improving C4 photosynthetic models and TEi through modification of gm .
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Affiliation(s)
- Varsha S. Pathare
- School of Biological SciencesWashington State UniversityPullmanWA99164‐4236USA
| | - Robert J. DiMario
- School of Biological SciencesWashington State UniversityPullmanWA99164‐4236USA
| | - Nuria Koteyeva
- School of Biological SciencesWashington State UniversityPullmanWA99164‐4236USA
- Laboratory of Anatomy and MorphologyV.L. Komarov Botanical Institute of the Russian Academy of Sciences197376St PetersburgRussia
| | - Asaph B. Cousins
- School of Biological SciencesWashington State UniversityPullmanWA99164‐4236USA
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Sagun JV, Chow WS, Ghannoum O. Leaf pigments and photosystems stoichiometry underpin photosynthetic efficiency of related C 3 , C-C 4 and C 4 grasses under shade. PHYSIOLOGIA PLANTARUM 2022; 174:e13819. [PMID: 36344438 DOI: 10.1111/ppl.13819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 09/12/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
The quantum yield of photosynthesis (QY, CO2 fixed per light absorbed) depends on the efficiency of light absorption, the coupling between light absorption and electron transport, and the coupling between electron transport and carbon metabolism. QY is generally lower in C3 relative to C4 plants at warm temperatures and differs among the C4 subtypes. We investigated the acclimation to shade of light absorption and electron transport in six representative grasses with C3 , C3 -C4 and C4 photosynthesis. Plants were grown under full (control) or 25% (shade) sunlight. We measured the in vivo activity and stoichiometry of PSI and PSII, leaf spectral properties and pigment contents, and photosynthetic enzyme activities. Under control growth-light conditions, C4 species had higher CO2 assimilation rates, which declined to a greater extent relative to the C3 species. Whole leaf PSII/PSI ratios were highest in the C3 species, while QY and cyclic electron flow (CEF) were highest in the C4 , NADP-ME species. Shade significantly reduced leaf PSII/PSI, linear electron flow (LEF) and CEF of most species. Overall, shade reduced leaf absorptance, especially in the green region, as well as carotenoid and chlorophyll contents in C4 more than non-C4 species. The NAD-ME species underwent the greatest reduction in leaf absorptance and pigments under shade. In conclusion, shade compromised QY the least in the C3 and the most in the C4 -NAD-ME species. Different sensitivity to shade was associated with the ability to maintain leaf absorptance and pigments. This is important for maximising light absorption and minimising photoprotection under low light.
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Affiliation(s)
- Julius Ver Sagun
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, Australia
| | - Wah Soon Chow
- ARC Centre of Excellence for Translational Photosynthesis, Research School of Biology, Australian National University, Canberra, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis, Hawkesbury Institute for the Environment, Western Sydney University, Penrith, Australia
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Zheng T, Yu Y, Kang H. Short-term elevated temperature and CO 2 promote photosynthetic induction in the C 3 plant Glycine max, but not in the C 4 plant Amaranthus tricolor. FUNCTIONAL PLANT BIOLOGY : FPB 2022; 49:995-1007. [PMID: 35908799 DOI: 10.1071/fp21363] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 07/10/2022] [Indexed: 06/15/2023]
Abstract
The continuous increases of atmospheric temperature and CO2 concentration will impact global photosynthesis. However, there are few studies considering the interaction of elevated temperature (eT) and elevated CO2 (eCO2 ) on dynamic photosynthesis, particularly for C4 species. We examine dynamic photosynthesis under four different temperature and [CO2 ] treatments: (1) 400ppm×28°C (CT); (2) 400ppm×33°C (CT+); (3) 800ppm×28°C (C+T); and (4) 800ppm×33°C (C+T+). In Glycine max L., the time required to reach 50% (T 50%A ) and 90% (T 90%A ) of full photosynthetic induction was smaller under the CT+, C+T, and C+T+ treatments than those under the CT treatment. In Amaranthus tricolor L., however, neither T 50%A nor T 90%A was not significantly affected by eT or eCO2 . In comparison with the CT treatment, the achieved carbon gain was increased by 58.3% (CT+), 112% (C+T), and 136.6% (C+T+) in G. max and was increased by 17.1% (CT+), 2.6% (C+T) and 56.9% (C+T+) in A. tricolor . The increases of achieved carbon gain in G. max were attributable to both improved photosynthetic induction efficiency (IE) and enhanced steady-state photosynthesis, whereas those in A. tricolor were attributable to enhanced steady-state photosynthesis.
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Affiliation(s)
- Tianyu Zheng
- Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
| | - Yuan Yu
- Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
| | - Huixing Kang
- Department of Ecology, College of Urban and Environmental Sciences, and Key Laboratory for Earth Surface Processes of the Ministry of Education, Peking University, Beijing 100871, China
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Bellasio C, Ermakova M. Reduction of bundle sheath size boosts cyclic electron flow in C 4 Setaria viridis acclimated to low light. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:1223-1237. [PMID: 35866447 PMCID: PMC9545969 DOI: 10.1111/tpj.15915] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/29/2022] [Accepted: 07/07/2022] [Indexed: 05/22/2023]
Abstract
When C4 leaves are exposed to low light, the CO2 concentration in the bundle sheath (BS) cells decreases, causing an increase in photorespiration relative to assimilation, and a consequent reduction in biochemical efficiency. These effects can be mitigated by complex acclimation syndromes, which are of primary importance for crop productivity but are not well studied. We unveil an acclimation strategy involving the coordination of electron transport processes. First, we characterize the anatomy, gas exchange and electron transport of C4 Setaria viridis grown under low light. Through a purposely developed biochemical model, we resolve the photon fluxes and reaction rates to explain how the concerted acclimation strategies sustain photosynthetic efficiency. Our results show that a smaller BS in low-light-grown plants limited leakiness (the ratio of CO2 leak rate out of the BS over the rate of supply via C4 acid decarboxylation) but sacrificed light harvesting and ATP production. To counter ATP shortage and maintain high assimilation rates, plants facilitated light penetration through the mesophyll and upregulated cyclic electron flow in the BS. This shade tolerance mechanism, based on the optimization of light reactions, is possibly more efficient than the known mechanisms involving the rearrangement of carbon metabolism, and could potentially lead to innovative strategies for crop improvement.
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Affiliation(s)
- Chandra Bellasio
- Department of BiologyUniversity of the Balearic Islands07122PalmaIlles BalearsSpain
- Centre of Excellence for Translational Photosynthesis, Research School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Maria Ermakova
- Centre of Excellence for Translational Photosynthesis, Research School of BiologyThe Australian National UniversityActonACT2601Australia
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Medeiros DB, Ishihara H, Guenther M, Rosado de Souza L, Fernie AR, Stitt M, Arrivault S. 13CO2 labeling kinetics in maize reveal impaired efficiency of C4 photosynthesis under low irradiance. PLANT PHYSIOLOGY 2022; 190:280-304. [PMID: 35751609 PMCID: PMC9434203 DOI: 10.1093/plphys/kiac306] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 06/06/2022] [Indexed: 06/01/2023]
Abstract
C4 photosynthesis allows faster photosynthetic rates and higher water and nitrogen use efficiency than C3 photosynthesis, but at the cost of lower quantum yield due to the energy requirement of its biochemical carbon concentration mechanism. It has also been suspected that its operation may be impaired in low irradiance. To investigate fluxes under moderate and low irradiance, maize (Zea mays) was grown at 550 µmol photons m-2 s-l and 13CO2 pulse-labeling was performed at growth irradiance or several hours after transfer to 160 µmol photons m-2 s-1. Analysis by liquid chromatography/tandem mass spectrometry or gas chromatography/mass spectrometry provided information about pool size and labeling kinetics for 32 metabolites and allowed estimation of flux at many steps in C4 photosynthesis. The results highlighted several sources of inefficiency in low light. These included excess flux at phosphoenolpyruvate carboxylase, restriction of decarboxylation by NADP-malic enzyme, and a shift to increased CO2 incorporation into aspartate, less effective use of metabolite pools to drive intercellular shuttles, and higher relative and absolute rates of photorespiration. The latter provides evidence for a lower bundle sheath CO2 concentration in low irradiance, implying that operation of the CO2 concentration mechanism is impaired in this condition. The analyses also revealed rapid exchange of carbon between the Calvin-Benson cycle and the CO2-concentration shuttle, which allows rapid adjustment of the balance between CO2 concentration and assimilation, and accumulation of large amounts of photorespiratory intermediates in low light that provides a major carbon reservoir to build up C4 metabolite pools when irradiance increases.
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Affiliation(s)
| | - Hirofumi Ishihara
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Manuela Guenther
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | | | - Alisdair R Fernie
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
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Liu L, Hao L, Zhang Y, Zhou H, Ma B, Cheng Y, Tian Y, Chang Z, Zheng Y. The CO 2 fertilization effect on leaf photosynthesis of maize ( Zea mays L.) depends on growth temperatures with changes in leaf anatomy and soluble sugars. FRONTIERS IN PLANT SCIENCE 2022; 13:890928. [PMID: 36061776 PMCID: PMC9437643 DOI: 10.3389/fpls.2022.890928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
Understanding the potential mechanisms and processes of leaf photosynthesis in response to elevated CO2 concentration ([CO2]) and temperature is critical for estimating the impacts of climatic change on the growth and yield in crops such as maize (Zea mays L.), which is a widely cultivated C4 crop all over the world. We examined the combined effect of elevated [CO2] and temperature on plant growth, leaf photosynthesis, stomatal traits, and biochemical compositions of maize with six environmental growth chambers controlling two CO2 levels (400 and 800 μmol mol-1) and three temperature regimes (25/19°C, 31/25°C, and 37/31°C). We found that leaf photosynthesis was significantly enhanced by increasing growth temperature from 25/19°C to 31/25°C independent of [CO2]. However, leaf photosynthesis drastically declined when the growth temperature was continually increased to 37/31°C at both ambient CO2 concentration (400 μmol mol-1, a[CO2]) and elevated CO2 concentration (800 μmol mol-1, e[CO2]). Meanwhile, we also found strong CO2 fertilization effect on maize plants grown at the highest temperature (37/31°C), as evidenced by the higher leaf photosynthesis at e[CO2] than that at a[CO2], although leaf photosynthesis was similar between a[CO2] and e[CO2] under the other two temperature regimes of 25/19°C and 31/25°C. Furthermore, we also found that e[CO2] resulted in an increase in leaf soluble sugar, which was positively related with leaf photosynthesis under the high temperature regime of 37/31°C (R 2 = 0.77). In addition, our results showed that e[CO2] substantially decreased leaf transpiration rates of maize plants, which might be partially attributed to the reduced stomatal openness as demonstrated by the declined stomatal width and stomatal area. These results suggest that the CO2 fertilization effect on plant growth and leaf photosynthesis of maize depends on growth temperatures through changing stomatal traits, leaf anatomy, and soluble sugar contents.
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Affiliation(s)
- Liang Liu
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
| | - Lihua Hao
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
| | - Yunxin Zhang
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
| | - Haoran Zhou
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, United States
| | - Baoguo Ma
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
| | - Yao Cheng
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
| | - Yinshuai Tian
- School of Landscape and Ecological Engineering, Hebei University of Engineering, Handan, China
| | - Zhijie Chang
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
| | - Yunpu Zheng
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, China
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11
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Zheng B, Zhao W, Ren T, Zhang X, Ning T, Liu P, Li G. Low Light Increases the Abundance of Light Reaction Proteins: Proteomics Analysis of Maize ( Zea mays L.) Grown at High Planting Density. Int J Mol Sci 2022; 23:ijms23063015. [PMID: 35328436 PMCID: PMC8955883 DOI: 10.3390/ijms23063015] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/27/2022] [Accepted: 03/08/2022] [Indexed: 02/04/2023] Open
Abstract
Maize (Zea mays L.) is usually planted at high density, so most of its leaves grow in low light. Certain morphological and physiological traits improve leaf photosynthetic capacity under low light, but how light absorption, transmission, and transport respond at the proteomic level remains unclear. Here, we used tandem mass tag (TMT) quantitative proteomics to investigate maize photosynthesis-related proteins under low light due to dense planting, finding increased levels of proteins related to photosystem II (PSII), PSI, and cytochrome b6f. These increases likely promote intersystem electron transport and increased PSI end electron acceptor abundance. OJIP transient curves revealed increases in some fluorescence parameters under low light: quantum yield for electron transport (φEo), probability that an electron moves beyond the primary acceptor QA- (ψo), efficiency/probability of electron transfer from intersystem electron carriers to reduction end electron acceptors at the PSI acceptor side (δRo), quantum yield for reduction of end electron acceptors at the PSI acceptor side (φRo), and overall performance up to the PSI end electron acceptors (PItotal). Thus, densely planted maize shows elevated light utilization through increased electron transport efficiency, which promotes coordination between PSII and PSI, as reflected by higher apparent quantum efficiency (AQE), lower light compensation point (LCP), and lower dark respiration rate (Rd).
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12
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Crawford JD, Cousins AB. Limitation of C4 photosynthesis by low carbonic anhydrase activity increases with temperature but does not influence mesophyll CO2 conductance. JOURNAL OF EXPERIMENTAL BOTANY 2022; 73:927-938. [PMID: 34698863 DOI: 10.1093/jxb/erab464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 10/23/2021] [Indexed: 06/13/2023]
Abstract
The CO2-concentrating mechanism (CCM) in C4 plants is initiated by the uptake of bicarbonate (HCO3-) via phosphoenolpyruvate carboxylase (PEPC). Generation of HCO3- for PEPC is determined by the interaction between mesophyll CO2 conductance and the hydration of CO2 to HCO3- by carbonic anhydrase (CA). Genetic reduction of CA was previously shown not to limit C4 photosynthesis under ambient atmospheric partial pressures of CO2 (pCO2). However, CA activity varies widely across C4 species and it is unknown if there are specific environmental conditions (e.g. high temperature) where CA may limit HCO3- production for C4 photosynthesis. Additionally, CA activity has been suggested to influence mesophyll conductance, but this has not been experimentally tested. We hypothesize that CA activity can limit PEPC at high temperatures, particularly at low pCO2, but does not directly influence gm. Here we tested the influence of genetically reduced CA activity on photosynthesis and gm in the C4 plant Zea mays under a range of pCO2 and temperatures. Reduced CA activity limited HCO3- production for C4 photosynthesis at low pCO2 as temperatures increased, but did not influence mesophyll conductance. Therefore, high leaf CA activity may enhance C4 photosynthesis under high temperature when stomatal conductance restricts the availability of atmospheric CO2.
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Affiliation(s)
- Joseph D Crawford
- School of Biological Sciences, Washington State University, Pullman, WA, USA
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, USA
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13
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Ermakova M, Osborn H, Groszmann M, Bala S, Bowerman A, McGaughey S, Byrt C, Alonso-Cantabrana H, Tyerman S, Furbank RT, Sharwood RE, von Caemmerer S. Expression of a CO 2-permeable aquaporin enhances mesophyll conductance in the C 4 species Setaria viridis. eLife 2021; 10:70095. [PMID: 34842138 PMCID: PMC8648302 DOI: 10.7554/elife.70095] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Accepted: 11/23/2021] [Indexed: 02/02/2023] Open
Abstract
A fundamental limitation of photosynthetic carbon fixation is the availability of CO2. In C4 plants, primary carboxylation occurs in mesophyll cytosol, and little is known about the role of CO2 diffusion in facilitating C4 photosynthesis. We have examined the expression, localization, and functional role of selected plasma membrane intrinsic aquaporins (PIPs) from Setaria italica (foxtail millet) and discovered that SiPIP2;7 is CO2-permeable. When ectopically expressed in mesophyll cells of Setaria viridis (green foxtail), SiPIP2;7 was localized to the plasma membrane and caused no marked changes in leaf biochemistry. Gas exchange and C18O16O discrimination measurements revealed that targeted expression of SiPIP2;7 enhanced the conductance to CO2 diffusion from the intercellular airspace to the mesophyll cytosol. Our results demonstrate that mesophyll conductance limits C4 photosynthesis at low pCO2 and that SiPIP2;7 is a functional CO2 permeable aquaporin that can improve CO2 diffusion at the airspace/mesophyll interface and enhance C4 photosynthesis.
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Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Hannah Osborn
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Michael Groszmann
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Soumi Bala
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Andrew Bowerman
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Samantha McGaughey
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Caitlin Byrt
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Hugo Alonso-Cantabrana
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Steve Tyerman
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture Food and Wine, University of Adelaide, Adelaide, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
| | - Robert E Sharwood
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia.,Hawkesbury Institute for the Environment, Western Sydney University, Richmond, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Science, Research School of Biology, Canberra, Australia
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14
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Ferguson JN, Fernandes SB, Monier B, Miller ND, Allen D, Dmitrieva A, Schmuker P, Lozano R, Valluru R, Buckler ES, Gore MA, Brown PJ, Spalding EP, Leakey ADB. Machine learning-enabled phenotyping for GWAS and TWAS of WUE traits in 869 field-grown sorghum accessions. PLANT PHYSIOLOGY 2021; 187:1481-1500. [PMID: 34618065 PMCID: PMC9040483 DOI: 10.1093/plphys/kiab346] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 06/29/2021] [Indexed: 05/04/2023]
Abstract
Sorghum (Sorghum bicolor) is a model C4 crop made experimentally tractable by extensive genomic and genetic resources. Biomass sorghum is studied as a feedstock for biofuel and forage. Mechanistic modeling suggests that reducing stomatal conductance (gs) could improve sorghum intrinsic water use efficiency (iWUE) and biomass production. Phenotyping to discover genotype-to-phenotype associations remains a bottleneck in understanding the mechanistic basis for natural variation in gs and iWUE. This study addressed multiple methodological limitations. Optical tomography and a machine learning tool were combined to measure stomatal density (SD). This was combined with rapid measurements of leaf photosynthetic gas exchange and specific leaf area (SLA). These traits were the subject of genome-wide association study and transcriptome-wide association study across 869 field-grown biomass sorghum accessions. The ratio of intracellular to ambient CO2 was genetically correlated with SD, SLA, gs, and biomass production. Plasticity in SD and SLA was interrelated with each other and with productivity across wet and dry growing seasons. Moderate-to-high heritability of traits studied across the large mapping population validated associations between DNA sequence variation or RNA transcript abundance and trait variation. A total of 394 unique genes underpinning variation in WUE-related traits are described with higher confidence because they were identified in multiple independent tests. This list was enriched in genes whose Arabidopsis (Arabidopsis thaliana) putative orthologs have functions related to stomatal or leaf development and leaf gas exchange, as well as genes with nonsynonymous/missense variants. These advances in methodology and knowledge will facilitate improving C4 crop WUE.
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Affiliation(s)
- John N Ferguson
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Samuel B Fernandes
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Brandon Monier
- Institute for Genomic Diversity, Cornell University, Ithaca, New
York 14853, USA
| | - Nathan D Miller
- Department of Botany, University of Wisconsin, Madison, Wisconsin
53706, USA
| | - Dylan Allen
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Anna Dmitrieva
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Peter Schmuker
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Roberto Lozano
- Plant Breeding and Genetics Section, School of Integrative Plant Science,
Cornell University, Ithaca, New York 14853, USA
| | - Ravi Valluru
- Institute for Genomic Diversity, Cornell University, Ithaca, New
York 14853, USA
- Present address: Lincoln Institute for Agri-Food Technology,
University of Lincoln, Lincoln LN2 2LG, UK
| | - Edward S Buckler
- Institute for Genomic Diversity, Cornell University, Ithaca, New
York 14853, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science,
Cornell University, Ithaca, New York 14853, USA
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science,
Cornell University, Ithaca, New York 14853, USA
| | - Patrick J Brown
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
- Present address: Section of Agricultural Plant Biology,
Department of Plant Sciences, University of California Davis, California 95616,
USA
| | - Edgar P Spalding
- Department of Botany, University of Wisconsin, Madison, Wisconsin
53706, USA
| | - Andrew D B Leakey
- Institute for Genomic Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
- Department of Crop Sciences, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
- Department of Plant Biology, University of Illinois at
Urbana-Champaign, Urbana, Illinois 61901, USA
- Author for communication: ,
Present address: Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA,
UK
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15
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Ferguson JN, Fernandes SB, Monier B, Miller ND, Allen D, Dmitrieva A, Schmuker P, Lozano R, Valluru R, Buckler ES, Gore MA, Brown PJ, Spalding EP, Leakey ADB. Machine learning-enabled phenotyping for GWAS and TWAS of WUE traits in 869 field-grown sorghum accessions. PLANT PHYSIOLOGY 2021; 187:1481-1500. [PMID: 34618065 DOI: 10.1093/plphys/kiab34] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 06/29/2021] [Indexed: 05/27/2023]
Abstract
Sorghum (Sorghum bicolor) is a model C4 crop made experimentally tractable by extensive genomic and genetic resources. Biomass sorghum is studied as a feedstock for biofuel and forage. Mechanistic modeling suggests that reducing stomatal conductance (gs) could improve sorghum intrinsic water use efficiency (iWUE) and biomass production. Phenotyping to discover genotype-to-phenotype associations remains a bottleneck in understanding the mechanistic basis for natural variation in gs and iWUE. This study addressed multiple methodological limitations. Optical tomography and a machine learning tool were combined to measure stomatal density (SD). This was combined with rapid measurements of leaf photosynthetic gas exchange and specific leaf area (SLA). These traits were the subject of genome-wide association study and transcriptome-wide association study across 869 field-grown biomass sorghum accessions. The ratio of intracellular to ambient CO2 was genetically correlated with SD, SLA, gs, and biomass production. Plasticity in SD and SLA was interrelated with each other and with productivity across wet and dry growing seasons. Moderate-to-high heritability of traits studied across the large mapping population validated associations between DNA sequence variation or RNA transcript abundance and trait variation. A total of 394 unique genes underpinning variation in WUE-related traits are described with higher confidence because they were identified in multiple independent tests. This list was enriched in genes whose Arabidopsis (Arabidopsis thaliana) putative orthologs have functions related to stomatal or leaf development and leaf gas exchange, as well as genes with nonsynonymous/missense variants. These advances in methodology and knowledge will facilitate improving C4 crop WUE.
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Affiliation(s)
- John N Ferguson
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Samuel B Fernandes
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Brandon Monier
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
| | - Nathan D Miller
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Dylan Allen
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Anna Dmitrieva
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Peter Schmuker
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Roberto Lozano
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853, USA
| | - Ravi Valluru
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
| | - Edward S Buckler
- Institute for Genomic Diversity, Cornell University, Ithaca, New York 14853, USA
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853, USA
| | - Michael A Gore
- Plant Breeding and Genetics Section, School of Integrative Plant Science, Cornell University, Ithaca, New York 14853, USA
| | - Patrick J Brown
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
| | - Edgar P Spalding
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Andrew D B Leakey
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61901, USA
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16
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Feng Y, Cui X, Shan H, Shi Z, Li F, Wang H, Zhu M, Zhong X. Effects of solar radiation on photosynthetic physiology of barren stalk differentiation in maize. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 312:111046. [PMID: 34620444 DOI: 10.1016/j.plantsci.2021.111046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Revised: 08/15/2021] [Accepted: 08/28/2021] [Indexed: 06/13/2023]
Abstract
Barren stalks and kernel abortion are the major obstacles that hinder maize production. After many years of inbreeding, our group produced a pair of barren stalk/non-barren stalk near-isogenic lines SN98A/SN98B. Under weak light stress, the barren stalk rate is up to 98 % in SN98A but zero in SN98B. Therefore, we consider that SN98A is a weak light-sensitive inbred line whereas SN98B is insensitive. In the present study, the near-isogenic lines SN98A/SN98B were used as test materials to conduct cytological and photosynthetic physiological analyses of the physiological mechanism associated with the differences in maize barren stalk induced by weak light stress. The results showed that weak light stress increased the accumulation of reactive oxygen species (ROS), decreased the function of chloroplasts, destroyed the normal rosette structure, inhibited photosynthetic electron transport, and enhanced lipid peroxidation. The actual photochemical quantum efficiency for PSI (Y(I)) and PSII (Y(II)), relative electron transfer rate for PSI (ETR(I)) and PSII (ETR(II)), and the P700 activities decreased significantly in the leaves of SN98A and SN98B under weak light stress, where the decreases were greater in SN98A than SN98B. After 10 days of shading treatment, the O2·- production rate, H2O2 contents, the yield of regulated energy dissipation (Y(NPQ)), the donor side restriction for PSI (Y(ND)) and the quantum efficiency of cyclic electron flow photochemistry were always higher in SN98A than SN98B, and the antioxidant enzyme activities were always lower in SN98A than those in SN98B. These results show that SN98B has a stronger ability to remove ROS at its source, and maintain the integrity of the structure and function of the photosynthetic system. This self-protection mechanism is an important physiological reason for its adaptation to weak light.
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Affiliation(s)
- Ying Feng
- Special Corn Institute, Shenyang Agricultural University, 110866, Shenyang, People's Republic of China
| | - Xue Cui
- Liaoning Province Forestry and Grassland Pest Control and Quarantine Workstation, 110000, Shenyang, People's Republic of China
| | - Hong Shan
- Liaoning Dongya Seed Co., Ltd, 110184, Shenyang, People's Republic of China
| | - Zhensheng Shi
- Special Corn Institute, Shenyang Agricultural University, 110866, Shenyang, People's Republic of China
| | - Fenghai Li
- Special Corn Institute, Shenyang Agricultural University, 110866, Shenyang, People's Republic of China
| | - Hongwei Wang
- Special Corn Institute, Shenyang Agricultural University, 110866, Shenyang, People's Republic of China
| | - Min Zhu
- Special Corn Institute, Shenyang Agricultural University, 110866, Shenyang, People's Republic of China
| | - Xuemei Zhong
- Special Corn Institute, Shenyang Agricultural University, 110866, Shenyang, People's Republic of China.
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17
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Sun W, Ma N, Huang H, Wei J, Ma S, Liu H, Zhang S, Zhang Z, Sui X, Li X. Photosynthetic contribution and characteristics of cucumber stems and petioles. BMC PLANT BIOLOGY 2021; 21:454. [PMID: 34615487 PMCID: PMC8493697 DOI: 10.1186/s12870-021-03233-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Accepted: 09/29/2021] [Indexed: 06/11/2023]
Abstract
BACKGROUND Photosynthesis in the green leafless blade tissues or organs of plants has been studied in some plants, but the photosynthetic characteristics of stems and petioles are poorly understood. Cucurbitaceous plants are climbing plants that have substantial stem and petiole biomass. Understanding the photosynthetic contribution of cucumber stems and petioles to their growth and the underlying molecular mechanisms are important for the regulating of growth in cucumber production. RESULTS In this study, the photosynthetic capacity of cucumber stems and petioles were determined by 14CO2 uptake. The total carbon fixed by the stems and petioles was approximately 4% of that fixed by one leaf blade in the cucumber seedling stage, while the proportion of the carbon accumulated in the stems and petioles that redistributed to sink organs (roots and shoot apexes) obviously increased under leafless conditions. The photosynthetic properties of cucumber stems and petioles were studied using a combination of electron microscopy and isotope tracers to compare these properties of stems and petioles with those of leaf blade using two genotypes of cucumber (dark green and light green). Compared with those of the leaf blades, the chlorophyll contents of the cucumber stems and petioles were lower, and the stems and petioles had lower chloroplast numbers and lower stoma numbers but higher thylakoid grana lamella numbers and larger stoma sizes. The Chl a/b ratios were also decreased in the petioles and stems compared with those in the leaf blades. The total photosynthetic rates of the stems and petioles were equivalent to 6 ~ 8% of that of one leaf blade, but the respiration rates were similar in all the three organs, with an almost net 0 photosynthetic rate in the stems and petioles. Transcriptome analysis showed that compared with the leaf blades, the stems and petioles has significantly different gene expression levels in photosynthesis, porphyrin and chlorophyll metabolism; photosynthetic antenna proteins; and carbon fixation. PEPC enzyme activities were higher in the stems and petioles than in the leaf blades, suggesting that the photosynthetic and respiratory mechanisms in stems and petioles are different from those in leaf blade, and these results are consistent with the gene expression data. CONCLUSIONS In this study, we confirmed the photosynthetic contribution to the growth of cucumber stems and petioles, and showed their similar photosynthetic patterns in the terms of anatomy, molecular biology and physiology, which were different from those of cucumber leaf blades.
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Affiliation(s)
- Weike Sun
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Ning Ma
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Hongyu Huang
- State Key Laboratory of Vegetable Germplasm Innovation, Tianjin Kernel Cucumber Research Institute, 301 Baidi Road, Nankai District, Tianjin, 300192, China
| | - Jingwei Wei
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Si Ma
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Huan Liu
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Shi Zhang
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Zhenxian Zhang
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Xiaolei Sui
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China
| | - Xin Li
- Department of Vegetable Science, Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops. College of Horticulture, China Agricultural University, Yuanmingyuan Xilu 2#, HaiDian District, Beijing, 100193, China.
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18
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von Caemmerer S. Updating the steady-state model of C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:6003-6017. [PMID: 34173821 PMCID: PMC8411607 DOI: 10.1093/jxb/erab266] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 06/06/2021] [Indexed: 05/22/2023]
Abstract
C4 plants play a key role in world agriculture. For example, C4 crops such as maize and sorghum are major contributors to food production in both developed and developing countries, and the C4 grasses sugarcane, miscanthus, and switchgrass are major plant sources of bioenergy. In the challenge to manipulate and enhance C4 photosynthesis, steady-state models of leaf photosynthesis provide an important tool for gas exchange analysis and thought experiments that can explore photosynthetic pathway changes. Here a previous C4 photosynthetic model developed by von Caemmerer and Furbank has been updated with new kinetic parameterization and temperature dependencies added. The parameterization was derived from experiments on the C4 monocot, Setaria viridis, which for the first time provides a cohesive parameterization. Mesophyll conductance and its temperature dependence have also been included, as this is an important step in the quantitative correlation between the initial slope of the CO2 response curve of CO2 assimilation and in vitro phosphoenolpyruvate carboxylase activity. Furthermore, the equations for chloroplast electron transport have been updated to include cyclic electron transport flow, and equations have been added to calculate the electron transport rate from measured CO2 assimilation rates.
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Affiliation(s)
- Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
- Correspondence:
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19
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von Caemmerer S. Updating the steady-state model of C4 photosynthesis. JOURNAL OF EXPERIMENTAL BOTANY 2021. [PMID: 34173821 DOI: 10.5061/dryad.zcrjdfnc3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
C4 plants play a key role in world agriculture. For example, C4 crops such as maize and sorghum are major contributors to food production in both developed and developing countries, and the C4 grasses sugarcane, miscanthus, and switchgrass are major plant sources of bioenergy. In the challenge to manipulate and enhance C4 photosynthesis, steady-state models of leaf photosynthesis provide an important tool for gas exchange analysis and thought experiments that can explore photosynthetic pathway changes. Here a previous C4 photosynthetic model developed by von Caemmerer and Furbank has been updated with new kinetic parameterization and temperature dependencies added. The parameterization was derived from experiments on the C4 monocot, Setaria viridis, which for the first time provides a cohesive parameterization. Mesophyll conductance and its temperature dependence have also been included, as this is an important step in the quantitative correlation between the initial slope of the CO2 response curve of CO2 assimilation and in vitro phosphoenolpyruvate carboxylase activity. Furthermore, the equations for chloroplast electron transport have been updated to include cyclic electron transport flow, and equations have been added to calculate the electron transport rate from measured CO2 assimilation rates.
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Affiliation(s)
- Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
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20
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Jaikumar NS, Stutz SS, Fernandes SB, Leakey ADB, Bernacchi CJ, Brown PJ, Long SP. Can improved canopy light transmission ameliorate loss of photosynthetic efficiency in the shade? An investigation of natural variation in Sorghum bicolor. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4965-4980. [PMID: 33914063 PMCID: PMC8219039 DOI: 10.1093/jxb/erab176] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 04/28/2021] [Indexed: 05/29/2023]
Abstract
Previous studies have found that maximum quantum yield of CO2 assimilation (Φ CO2,max,app) declines in lower canopies of maize and miscanthus, a maladaptive response to self-shading. These observations were limited to single genotypes, leaving it unclear whether the maladaptive shade response is a general property of this C4 grass tribe, the Andropogoneae. We explored the generality of this maladaptation by testing the hypothesis that erect leaf forms (erectophiles), which allow more light into the lower canopy, suffer less of a decline in photosynthetic efficiency than drooping leaf (planophile) forms. On average, Φ CO2,max,app declined 27% in lower canopy leaves across 35 accessions, but the decline was over twice as great in planophiles than in erectophiles. The loss of photosynthetic efficiency involved a decoupling between electron transport and assimilation. This was not associated with increased bundle sheath leakage, based on 13C measurements. In both planophiles and erectophiles, shaded leaves had greater leaf absorptivity and lower activities of key C4 enzymes than sun leaves. The erectophile form is considered more productive because it allows a more effective distribution of light through the canopy to support photosynthesis. We show that in sorghum, it provides a second benefit, maintenance of higher Φ CO2,max,app to support efficient use of that light resource.
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Affiliation(s)
- Nikhil S Jaikumar
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Samantha S Stutz
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Samuel B Fernandes
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Andrew D B Leakey
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Carl J Bernacchi
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- USDA ARS Global Change and Photosynthesis Research Unit, Urbana, IL 61801, USA
| | - Patrick J Brown
- Department of Plant Sciences, University of California at Davis, Davis, CA 95616, USA
| | - Stephen P Long
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Lancaster Environment Centre, University of Lancaster, Lancaster LA1 4YQ, UK
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21
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Ermakova M, Bellasio C, Fitzpatrick D, Furbank RT, Mamedov F, von Caemmerer S. Upregulation of bundle sheath electron transport capacity under limiting light in C 4 Setaria viridis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 106:1443-1454. [PMID: 33772896 PMCID: PMC9291211 DOI: 10.1111/tpj.15247] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 02/15/2021] [Accepted: 03/22/2021] [Indexed: 05/22/2023]
Abstract
C4 photosynthesis is a biochemical pathway that operates across mesophyll and bundle sheath (BS) cells to increase CO2 concentration at the site of CO2 fixation. C4 plants benefit from high irradiance but their efficiency decreases under shade, causing a loss of productivity in crop canopies. We investigated shade acclimation responses of Setaria viridis, a model monocot of NADP-dependent malic enzyme subtype, focussing on cell-specific electron transport capacity. Plants grown under low light (LL) maintained CO2 assimilation rates similar to high light plants but had an increased chlorophyll and light-harvesting-protein content, predominantly in BS cells. Photosystem II (PSII) protein abundance, oxygen-evolving activity and the PSII/PSI ratio were enhanced in LL BS cells, indicating a higher capacity for linear electron flow. Abundances of PSI, ATP synthase, Cytochrome b6 f and the chloroplast NAD(P)H dehydrogenase complex, which constitute the BS cyclic electron flow machinery, were also increased in LL plants. A decline in PEP carboxylase activity in mesophyll cells and a consequent shortage of reducing power in BS chloroplasts were associated with a more oxidised plastoquinone pool in LL plants and the formation of PSII - light-harvesting complex II supercomplexes with an increased oxygen evolution rate. Our results suggest that the supramolecular composition of PSII in BS cells is adjusted according to the redox state of the plastoquinone pool. This discovery contributes to the understanding of the acclimation of PSII activity in C4 plants and will support the development of strategies for crop improvement, including the engineering of C4 photosynthesis into C3 plants.
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Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
| | - Chandra Bellasio
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
- University of the Balearic IslandsPalmaIlles Balears07122Spain
| | - Duncan Fitzpatrick
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
| | - Fikret Mamedov
- Molecular BiomimeticsDepartment of Chemistry – Ångström LaboratoryUppsala UniversityUppsala75 120Sweden
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonAustralian Capital Territory2601Australia
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22
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Ermakova M, Arrivault S, Giuliani R, Danila F, Alonso‐Cantabrana H, Vlad D, Ishihara H, Feil R, Guenther M, Borghi GL, Covshoff S, Ludwig M, Cousins AB, Langdale JA, Kelly S, Lunn JE, Stitt M, von Caemmerer S, Furbank RT. Installation of C 4 photosynthetic pathway enzymes in rice using a single construct. PLANT BIOTECHNOLOGY JOURNAL 2021; 19:575-588. [PMID: 33016576 PMCID: PMC7955876 DOI: 10.1111/pbi.13487] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/08/2020] [Accepted: 09/23/2020] [Indexed: 05/06/2023]
Abstract
Introduction of a C4 photosynthetic mechanism into C3 crops offers an opportunity to improve photosynthetic efficiency, biomass and yield in addition to potentially improving nitrogen and water use efficiency. To create a two-cell metabolic prototype for an NADP-malic enzyme type C4 rice, we transformed Oryza sativa spp. japonica cultivar Kitaake with a single construct containing the coding regions of carbonic anhydrase, phosphoenolpyruvate (PEP) carboxylase, NADP-malate dehydrogenase, pyruvate orthophosphate dikinase and NADP-malic enzyme from Zea mays, driven by cell-preferential promoters. Gene expression, protein accumulation and enzyme activity were confirmed for all five transgenes, and intercellular localization of proteins was analysed. 13 CO2 labelling demonstrated a 10-fold increase in flux though PEP carboxylase, exceeding the increase in measured in vitro enzyme activity, and estimated to be about 2% of the maize photosynthetic flux. Flux from malate via pyruvate to PEP remained low, commensurate with the low NADP-malic enzyme activity observed in the transgenic lines. Physiological perturbations were minor and RNA sequencing revealed no substantive effects of transgene expression on other endogenous rice transcripts associated with photosynthesis. These results provide promise that, with enhanced levels of the C4 proteins introduced thus far, a functional C4 pathway is achievable in rice.
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Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACTAustralia
| | | | - Rita Giuliani
- School of Biological SciencesMolecular Plant SciencesWashington State UniversityPullmanWAUSA
| | - Florence Danila
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACTAustralia
| | - Hugo Alonso‐Cantabrana
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACTAustralia
- Grains Research and Development CorporationBartonACTAustralia
| | - Daniela Vlad
- Department of Plant SciencesUniversity of OxfordOxfordUK
| | - Hirofumi Ishihara
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Regina Feil
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Manuela Guenther
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Gian Luca Borghi
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Sarah Covshoff
- Department of Plant SciencesUniversity of CambridgeCambridgeUK
| | - Martha Ludwig
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Asaph B. Cousins
- School of Biological SciencesMolecular Plant SciencesWashington State UniversityPullmanWAUSA
| | | | - Steven Kelly
- Department of Plant SciencesUniversity of OxfordOxfordUK
| | - John E. Lunn
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Mark Stitt
- Max Planck Institute of Molecular Plant PhysiologyPotsdam‐GolmGermany
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACTAustralia
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACTAustralia
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23
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Danila FR, Thakur V, Chatterjee J, Bala S, Coe RA, Acebron K, Furbank RT, von Caemmerer S, Quick WP. Bundle sheath suberisation is required for C 4 photosynthesis in a Setaria viridis mutant. Commun Biol 2021; 4:254. [PMID: 33637850 PMCID: PMC7910553 DOI: 10.1038/s42003-021-01772-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 02/01/2021] [Indexed: 02/05/2023] Open
Abstract
C4 photosynthesis provides an effective solution for overcoming the catalytic inefficiency of Rubisco. The pathway is characterised by a biochemical CO2 concentrating mechanism that operates across mesophyll and bundle sheath (BS) cells and relies on a gas tight BS compartment. A screen of a mutant population of Setaria viridis, an NADP-malic enzyme type C4 monocot, generated using N-nitroso-N-methylurea identified a mutant with an amino acid change in the gene coding region of the ABCG transporter, a step in the suberin synthesis pathway. Here, Nile red staining, TEM, and GC/MS confirmed the alteration in suberin deposition in the BS cell wall of the mutant. We show that this has disrupted the suberin lamellae of BS cell wall and increased BS conductance to CO2 diffusion more than two-fold in the mutant. Consequently, BS CO2 partial pressure is reduced and CO2 assimilation was impaired in the mutant. Our findings provide experimental evidence that a functional suberin lamellae is an essential anatomical feature for efficient C4 photosynthesis in NADP-ME plants like S. viridis and have implications for engineering strategies to ensure future food security.
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Affiliation(s)
- Florence R Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia.
| | - Vivek Thakur
- Department of Systems and Computational Biology, School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Jolly Chatterjee
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Soumi Bala
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Robert A Coe
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Kelvin Acebron
- International Rice Research Institute, Los Baños, Laguna, Philippines
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - William Paul Quick
- International Rice Research Institute, Los Baños, Laguna, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
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24
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Pignon CP, Long SP. Retrospective analysis of biochemical limitations to photosynthesis in 49 species: C 4 crops appear still adapted to pre-industrial atmospheric [CO 2 ]. PLANT, CELL & ENVIRONMENT 2020; 43:2606-2622. [PMID: 32743797 DOI: 10.1111/pce.13863] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 06/23/2020] [Accepted: 07/24/2020] [Indexed: 06/11/2023]
Abstract
Leaf CO2 uptake (A) in C4 photosynthesis is limited by the maximum apparent rate of PEPc carboxylation (Vpmax ) at low intercellular [CO2 ] (ci ) with a sharp transition to a ci -saturated rate (Vmax ) due to co-limitation by ribulose-1:5-bisphosphate carboxylase/oxygenase (Rubisco) and regeneration of PEP. The response of A to ci has been widely used to determine these two parameters. Vmax and Vpmax depend on different enzymes but draw on a shared pool of leaf resources, such that resource distribution is optimized, and A maximized, when Vmax and Vpmax are co-limiting. We collected published A/ci curves in 49 C4 species and assessed variation in photosynthetic traits between phylogenetic groups, and as a function of atmospheric [CO2 ]. The balance of Vmax -Vpmax varied among evolutionary lineages and C4 subtypes. Operating A was strongly Vmax -limited, such that re-allocation of resources from Vpmax towards Vmax was predicted to improve A by 12% in C4 crops. This would not require additional inputs but rather altered partitioning of existing leaf nutrients, resulting in increased water and nutrient-use efficiency. Optimal partitioning was achieved only in plants grown at pre-industrial atmospheric [CO2 ], suggesting C4 crops have not adjusted to the rapid increase in atmospheric [CO2 ] of the past few decades.
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Affiliation(s)
- Charles P Pignon
- Carl Woese Institute for Genomic Biology and Departments of Crop Sciences and Plant Biology, University of Illinois, Urbana, Illinois, USA
| | - Stephen P Long
- Carl Woese Institute for Genomic Biology and Departments of Crop Sciences and Plant Biology, University of Illinois, Urbana, Illinois, USA
- Lancaster Environment Centre, University of Lancaster, UK
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25
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Sonawane BV, Cousins AB. Mesophyll CO 2 conductance and leakiness are not responsive to short- and long-term soil water limitations in the C 4 plant Sorghum bicolor. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:1590-1602. [PMID: 32438487 DOI: 10.1111/tpj.14849] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 04/30/2020] [Accepted: 05/05/2020] [Indexed: 05/13/2023]
Abstract
Breeding economically important C4 crops for enhanced whole-plant water-use efficiency (WUEplant ) is needed for sustainable agriculture. WUEplant is a complex trait and an efficient phenotyping method that reports on components of WUEplant , such as intrinsic water-use efficiency (WUEi , the rate of leaf CO2 assimilation relative to water loss via stomatal conductance), is needed. In C4 plants, theoretical models suggest that leaf carbon isotope composition (δ13 C), when the efficiency of the CO2 -concentrating mechanism (leakiness, ϕ) remains constant, can be used to screen for WUEi . The limited information about how ϕ responds to water limitations confines the application of δ13 C for WUEi screening of C4 crops. The current research aimed to test the response of ϕ to short- or long-term moderate water limitations, and the relationship of δ13 C with WUEi and WUEplant , by addressing potential mesophyll CO2 conductance (gm ) and biochemical limitations in the C4 plant Sorghum bicolor. We demonstrate that gm and ϕ are not responsive to short- or long-term water limitations. Additionally, δ13 C was not correlated with gas-exchange estimates of WUEi under short- and long-term water limitations, but showed a significant negative relationship with WUEplant . The observed association between the δ13 C and WUEplant suggests an intrinsic link of δ13 C with WUEi in this C4 plant, and can potentially be used as a screening tool for WUEplant in sorghum.
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Affiliation(s)
- Balasaheb V Sonawane
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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26
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Tazoe Y, Ishikawa N, Shikanai T, Ishiyama K, Takagi D, Makino A, Sato F, Endo T. Overproduction of PGR5 enhances the electron sink downstream of photosystem I in a C 4 plant, Flaveria bidentis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:814-823. [PMID: 32314445 DOI: 10.1111/tpj.14774] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 03/31/2020] [Accepted: 04/07/2020] [Indexed: 05/25/2023]
Abstract
C4 plants can fix CO2 efficiently using CO2 -concentrating mechanisms (CCMs), but they require additional ATP. To supply the additional ATP, C4 plants operate at higher rates of cyclic electron transport around photosystem I (PSI), in which electrons are transferred from ferredoxin to plastoquinone. Recently, it has been reported that the NAD(P)H dehydrogenase-like complex (NDH) accumulated in the thylakoid membrane in leaves of C4 plants, making it a candidate for the additional synthesis of ATP used in the CCM. In addition, C4 plants have higher levels of PROTON GRADIENT REGULATION 5 (PGR5) expression, but it has been unknown how PGR5 functions in C4 photosynthesis. In this study, PGR5 was overexpressed in a C4 dicot, Flaveria bidentis. In PGR5-overproducing (OP) lines, PGR5 levels were 2.3- to 3.0-fold greater compared with wild-type plants. PGR5-like PHOTOSYNTHETIC PHENOTYPE 1 (PGRL1), which cooperates with PGR5, increased with PGR5. A spectroscopic analysis indicated that in the PGR5-OP lines, the acceptor side limitation of PSI was reduced in response to a rapid increase in photon flux density. Although it did not affect CO2 assimilation, the overproduction of PGR5 contributed to an enhanced electron sink downstream of PSI.
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Affiliation(s)
- Youshi Tazoe
- Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8052, Japan
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-0845, Japan
- CREST, JST, Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
- Faculty of Agro-Food Science, Niigata Agro-Food University, Tainai, Niigata, 959-2702, Japan
| | - Noriko Ishikawa
- Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8052, Japan
| | - Toshiharu Shikanai
- CREST, JST, Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
- Graduate School of Science, Kyoto University, Sakyo, Kyoto, 606-8052, Japan
| | - Keiki Ishiyama
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-0845, Japan
| | - Daisuke Takagi
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-0845, Japan
- Faculty of Agriculture, Setsunan University, Hirakata, Osaka, 573-0101, Japan
| | - Amane Makino
- Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, 980-0845, Japan
- CREST, JST, Gobancho, Chiyoda-ku, Tokyo, 102-0076, Japan
| | - Fumihiko Sato
- Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8052, Japan
| | - Tsuyoshi Endo
- Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8052, Japan
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27
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Serrano-Romero EA, Cousins AB. Cold acclimation of mesophyll conductance, bundle-sheath conductance and leakiness in Miscanthus × giganteus. THE NEW PHYTOLOGIST 2020; 226:1594-1606. [PMID: 32112409 DOI: 10.1111/nph.16503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 02/16/2020] [Indexed: 06/10/2023]
Abstract
The cold acclimations of mesophyll conductance (gm ), bundle-sheath conductance (gbs ) and the CO2 concentrating mechanism (CCM) of C4 plants have not been well studied. Here, we estimated the temperature response of gm , gbs and leakiness (ϕ), the amount of concentrated CO2 that escapes the bundle-sheath cells, for the chilling-tolerant C4 plant Miscanthus × giganteus grown at 14 and 25°C. To estimate these parameters, we combined the C4 -enzyme-limited photosynthesis model and the Δ13 C discrimination model. These combined models were parameterised using in vitro activities of carbonic anhydrase (CA), pyruvate, phosphate dikinase (PPDK), ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), and phosphoenolpyruvate carboxylase (PEPc). Cold-grown Miscanthus plants increased in vitro activities of RuBisCO and PPDK but decreased PEPc activity compared with warm-grown plants. Mesophyll conductance and gbs responded strongly to measurement temperatures but did not differ between plants from the two growth temperatures. Furthermore, modelling showed that ϕ increased with measurement temperatures for both cold-grown and warm-grown plants, but was only marginally larger in cold-grown compared with warm-grown plants. Our results in Miscanthus support that gm and gbs are unresponsive to growth temperature and that the CCM is able to acclimate to cold through increased activity of PPDK and RuBisCO.
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Affiliation(s)
| | - Asaph B Cousins
- Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
- School of Biological Sciences, Washington State University, Pullman, WA, 99164-4236, USA
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28
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Cousins AB, Mullendore DL, Sonawane BV. Recent developments in mesophyll conductance in C3, C4, and crassulacean acid metabolism plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:816-830. [PMID: 31960507 DOI: 10.1111/tpj.14664] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/19/2019] [Indexed: 05/24/2023]
Abstract
The conductance of carbon dioxide (CO2 ) from the substomatal cavities to the initial sites of CO2 fixation (gm ) can significantly reduce the availability of CO2 for photosynthesis. There have been many recent reviews on: (i) the importance of gm for accurately modelling net rates of CO2 assimilation, (ii) on how leaf biochemical and anatomical factors influence gm , (iii) the technical limitation of estimating gm , which cannot be directly measured, and (iv) how gm responds to long- and short-term changes in growth and measurement environmental conditions. Therefore, this review will highlight these previous publications but will attempt not to repeat what has already been published. We will instead initially focus on the recent developments on the two-resistance model of gm that describe the potential of photorespiratory and respiratory CO2 released within the mitochondria to diffuse directly into both the chloroplast and the cytosol. Subsequently, we summarize recent developments in the three-dimensional (3-D) reaction-diffusion models and 3-D image analysis that are providing new insights into how the complex structure and organization of the leaf influences gm . Finally, because most of the reviews and literature on gm have traditionally focused on C3 plants we review in the final sections some of the recent developments, current understanding and measurement techniques of gm in C4 and crassulacean acid metabolism (CAM) plants. These plants have both specialized leaf anatomy and either a spatially or temporally separated CO2 concentrating mechanisms (C4 and CAM, respectively) that influence how we interpret and estimate gm compared with a C3 plants.
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Affiliation(s)
- Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Daniel L Mullendore
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Balasaheb V Sonawane
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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29
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Ermakova M, Danila FR, Furbank RT, von Caemmerer S. On the road to C 4 rice: advances and perspectives. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 101:940-950. [PMID: 31596523 PMCID: PMC7065233 DOI: 10.1111/tpj.14562] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 09/27/2019] [Accepted: 10/03/2019] [Indexed: 05/18/2023]
Abstract
The international C4 rice consortium aims to introduce into rice a high capacity photosynthetic mechanism, the C4 pathway, to increase yield. The C4 pathway is characterised by a complex combination of biochemical and anatomical specialisation that ensures high CO2 partial pressure at RuBisCO sites in bundle sheath (BS) cells. Here we report an update of the progress of the C4 rice project. Since its inception in 2008 there has been an exponential growth in synthetic biology and molecular tools. Golden Gate cloning and synthetic promoter systems have facilitated gene building block approaches allowing multiple enzymes and metabolite transporters to be assembled and expressed from single gene constructs. Photosynthetic functionalisation of the BS in rice remains an important step and there has been some success overexpressing transcription factors in the cytokinin signalling network which influence chloroplast volume. The C4 rice project has rejuvenated the research interest in C4 photosynthesis. Comparative anatomical studies now point to critical features essential for the design. So far little attention has been paid to the energetics. C4 photosynthesis has a greater ATP requirement, which is met by increased cyclic electron transport in BS cells. We hypothesise that changes in energy statues may drive this increased capacity for cyclic electron flow without the need for further modification. Although increasing vein density will ultimately be necessary for high efficiency C4 rice, our modelling shows that small amounts of C4 photosynthesis introduced around existing veins could already provide benefits of increased photosynthesis on the road to C4 rice.
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Affiliation(s)
- Maria Ermakova
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Florence R. Danila
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Robert T. Furbank
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational PhotosynthesisDivision of Plant ScienceResearch School of BiologyThe Australian National UniversityActonACT2601Australia
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30
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Yabiku T, Ueno O. Structural and photosynthetic re-acclimation to low light in C4 maize leaves that developed under high light. ANNALS OF BOTANY 2019; 124:437-445. [PMID: 31127287 PMCID: PMC6798838 DOI: 10.1093/aob/mcz092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 05/23/2019] [Indexed: 05/26/2023]
Abstract
BACKGROUND AND AIMS C4 plants have higher photosynthetic capacity than C3 plants, but this advantage comes at an energetic cost that is problematic under low light. In the crop canopy, lower leaves first develop under high light but later experience low light because of mutual shading. To explore the re-acclimation of C4 leaves to low light, we investigated the structural and physiological changes of the leaves of maize plants grown in shaded pots. METHODS Plants were first grown under high light, and then some of them were shaded (20 % of sunlight) for 3 weeks. Four types of leaves were examined: new leaves that developed under low light during shading (L), new leaves that developed under high light (H), mature leaves that developed under high light before shading and were then subjected to low light (H-L) and mature leaves that always experienced high light (H-H). KEY RESULTS The leaf mass per area, nitrogen and chlorophyll contents per unit leaf area, chlorophyll a/b ratio and activities of C3 and C4 photosynthetic enzymes were lower in H-L than in H-H leaves and in L than in H leaves. Unlike L leaves, H-L leaves maintained the thickness and framework of the Kranz anatomy of H leaves, but chloroplast contents in H-L leaves were reduced. This reduction of chloroplast contents was achieved mainly by reducing the size of chloroplasts. Although grana of mesophyll chloroplasts were more developed in L leaves than in H leaves, there were no differences between H-L and H-H leaves. The light curves of photosynthesis in H-L and L leaves were very similar and showed traits of shade leaves. CONCLUSIONS Mature maize leaves that developed under high light re-acclimate to low-light environments by adjusting their biochemical traits and chloroplast contents to resemble shade leaves but maintain the anatomical framework of sun leaves.
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Affiliation(s)
- Takayuki Yabiku
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Nishi-ku, Fukuoka, Japan
- NARO Tohoku Agricultural Research Center, Shimokuriyagawa, Morioka, Iwate, Japan
| | - Osamu Ueno
- Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University, Nishi-ku, Fukuoka, Japan
- Faculty of Agriculture, Kyushu University, Nishi-ku, Fukuoka, Japan
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Poorter H, Niinemets Ü, Ntagkas N, Siebenkäs A, Mäenpää M, Matsubara S, Pons T. A meta-analysis of plant responses to light intensity for 70 traits ranging from molecules to whole plant performance. THE NEW PHYTOLOGIST 2019; 223:1073-1105. [PMID: 30802971 DOI: 10.1111/nph.15754] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 02/04/2019] [Indexed: 05/19/2023]
Abstract
By means of meta-analyses we determined how 70 traits related to plant anatomy, morphology, chemistry, physiology, growth and reproduction are affected by daily light integral (DLI; mol photons m-2 d-1 ). A large database including 500 experiments with 760 plant species enabled us to determine generalized dose-response curves. Many traits increase with DLI in a saturating fashion. Some showed a more than 10-fold increase over the DLI range of 1-50 mol m-2 d-1 , such as the number of seeds produced per plant and the actual rate of photosynthesis. Strong decreases with DLI (up to three-fold) were observed for leaf area ratio and leaf payback time. Plasticity differences among species groups were generally small compared with the overall responses to DLI. However, for a number of traits, including photosynthetic capacity and realized growth, we found woody and shade-tolerant species to have lower plasticity. We further conclude that the direction and degree of trait changes adheres with responses to plant density and to vertical light gradients within plant canopies. This synthesis provides a strong quantitative basis for understanding plant acclimation to light, from molecular to whole plant responses, but also identifies the variables that currently form weak spots in our knowledge, such as respiration and reproductive characteristics.
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Affiliation(s)
- Hendrik Poorter
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
- Department of Biological Sciences, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Ülo Niinemets
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 1, Tartu, 51006, Estonia
- Estonian Academy of Sciences, Kohtu 6, Tallinn, 10130, Estonia
| | - Nikolaos Ntagkas
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
| | - Alrun Siebenkäs
- Department for Nature Conservation and Landscape Planning, Anhalt University of Applied Sciences, Strenzfelder Allee 28, 06406, Bernburg, Germany
| | - Maarit Mäenpää
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
- Department of Environmental and Biological Sciences, University of Eastern Finland, FI-80101, Joensuu, Finland
| | - Shizue Matsubara
- Plant Sciences (IBG-2), Forschungszentrum Jülich GmbH, D-52425, Jülich, Germany
| | - ThijsL Pons
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, 3512 PN, Utrecht, the Netherlands
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32
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Danila FR, Quick WP, White RG, von Caemmerer S, Furbank RT. Response of plasmodesmata formation in leaves of C 4 grasses to growth irradiance. PLANT, CELL & ENVIRONMENT 2019; 42:2482-2494. [PMID: 30965390 DOI: 10.1111/pce.13558] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
Rapid metabolite diffusion across the mesophyll (M) and bundle sheath (BS) cell interface in C4 leaves is a key requirement for C4 photosynthesis and occurs via plasmodesmata (PD). Here, we investigated how growth irradiance affects PD density between M and BS cells and between M cells in two C4 species using our PD quantification method, which combines three-dimensional laser confocal fluorescence microscopy and scanning electron microscopy. The response of leaf anatomy and physiology of NADP-ME species, Setaria viridis and Zea mays to growth under different irradiances, low light (100 μmol m-2 s-1 ), and high light (1,000 μmol m-2 s-1 ), was observed both at seedling and established growth stages. We found that the effect of growth irradiance on C4 leaf PD density depended on plant age and species. The high light treatment resulted in two to four-fold greater PD density per unit leaf area than at low light, due to greater area of PD clusters and greater PD size in high light plants. These results along with our finding that the effect of light on M-BS PD density was not tightly linked to photosynthetic capacity suggest a complex mechanism underlying the dynamic response of C4 leaf PD formation to growth irradiance.
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Affiliation(s)
- Florence R Danila
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - William Paul Quick
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- International Rice Research Institute, Los Baños, Laguna, 4030, Philippines
- University of Sheffield, Sheffield, UK
| | - Rosemary G White
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia
| | - Susanne von Caemmerer
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
| | - Robert T Furbank
- Research School of Biology, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra, Australian Capital Territory, 2601, Australia
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, 2601, Australia
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Zheng Y, Li F, Hao L, Yu J, Guo L, Zhou H, Ma C, Zhang X, Xu M. Elevated CO 2 concentration induces photosynthetic down-regulation with changes in leaf structure, non-structural carbohydrates and nitrogen content of soybean. BMC PLANT BIOLOGY 2019; 19:255. [PMID: 31195963 PMCID: PMC6567668 DOI: 10.1186/s12870-019-1788-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 04/18/2019] [Indexed: 05/21/2023]
Abstract
BACKGROUND Understanding the mechanisms of crops in response to elevated CO2 concentrations is pivotal to estimating the impacts of climate change on the global agricultural production. Based on earlier results of the "doubling-CO2 concentration" experiments, many current climate models may overestimate the CO2 fertilization effect on crops, and meanwhile, underestimate the potential impacts of future climate change on global agriculture ecosystem when the atmospheric CO2 concentration goes beyond the optimal levels for crop growth. RESULTS This study examined the photosynthetic response of soybean (Glycine max (L.) Merr.) to elevated CO2 concentration associated with changes in leaf structure, non-structural carbohydrates and nitrogen content with environmental growth chambers where the CO2 concentration was controlled at 400, 600, 800, 1000, 1200, 1400, 1600 ppm. We found CO2-induced down-regulation of leaf photosynthesis as evidenced by the consistently declined leaf net photosynthetic rate (An) with elevated CO2 concentrations. This down-regulation of leaf photosynthesis was evident in biochemical and photochemical processes since the maximum carboxylation rate (Vcmax) and the maximum electron transport rate (Jmax) were dramatically decreased at higher CO2 concentrations exceeding their optimal values of about 600 ppm and 400 ppm, respectively. Moreover, the down-regulation of leaf photosynthesis at high CO2 concentration was partially attributed to the reduced stomatal conductance (Gs) as demonstrated by the declines in stomatal density and stomatal area as well as the changes in the spatial distribution pattern of stomata. In addition, the smaller total mesophyll size (palisade and spongy tissues) and the lower nitrogen availability may also contribute to the down-regulation of leaf photosynthesis when soybean subjected to high CO2 concentration environment. CONCLUSIONS Down-regulation of leaf photosynthesis associated with the changes in stomatal traits, mesophyll tissue size, non-structural carbohydrates, and nitrogen availability of soybean in response to future high atmospheric CO2 concentration and climate change.
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Affiliation(s)
- Yunpu Zheng
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, 056038 China
| | - Fei Li
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, 056038 China
| | - Lihua Hao
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, 056038 China
| | - Jingjin Yu
- School of Agro-Grassland Science, Nanjing Agricultural University, Nanjing, 210095 People’s Republic of China
| | - Lili Guo
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, 056038 China
| | - Haoran Zhou
- Department of Biology, University of Pennsylvania, Philadelphia, PA 19104 USA
| | - Chao Ma
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, 056038 China
| | - Xixi Zhang
- School of Water Conservancy and Hydropower, Hebei University of Engineering, Handan, 056038 China
| | - Ming Xu
- Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions, College of Environment and Planning, Henan University, Kaifeng, 475004 China
- Center for Remote Sensing and Spatial Analysis, Department of Ecology, Evolution and Natural Resources, Rutgers University, 14 College Farm Road, New Brunswick, NJ 08901 USA
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Bilska-Kos A, Panek P, Szulc-Głaz A, Ochodzki P, Cisło A, Zebrowski J. Chilling-induced physiological, anatomical and biochemical responses in the leaves of Miscanthus × giganteus and maize (Zea mays L.). JOURNAL OF PLANT PHYSIOLOGY 2018; 228:178-188. [PMID: 29945073 DOI: 10.1016/j.jplph.2018.05.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/28/2018] [Accepted: 05/15/2018] [Indexed: 05/21/2023]
Abstract
Miscanthus × giganteus and Zea mays, closely-related C4 grasses, originated from warm climates react differently to low temperature. To investigate the response to cold (12-14 °C) in these species, the photosynthetic and anatomical parameters as well as biochemical properties of the cell wall were studied. The research was performed using M. giganteus (MG) and two Z. mays lines differentiated for chilling-sensitivity: chilling-tolerant (Zm-T) and chilling-sensitive (Zm-S). The chilled plants of Zm-S line demonstrated strong inhibition of net CO2 assimilation and a clear decrease in F'v/F'm, Fv/Fm and ɸPSII, while in MG and Zm-T plants these parameters were almost unchanged. The anatomical studies revealed that MG plants had thinner leaves, epidermis and mesophyll cell layer as well as thicker cell walls in the comparison to both maize lines. Cold led to an increase in leaf thickness and mesophyll cell layer thickness in the Zm-T maize line, while the opposite response was observed in Zm-S. In turn, in chilled plants of MG and Zm-T lines, some anatomical parameters associated with bundle sheath cells were higher. In addition, Zm-S line showed the strong increase in the cell wall thickness at cold for mesophyll and bundle sheath cells. Chilling-treatment induced the changes in the cell wall biochemistry of tested species, mainly in the content of glucuronoarabinoxylan, uronic acid, β-glucan and phenolic compounds. This work presents a new approach in searching of mechanism(s) of tolerance/sensitivity to low temperature in two thermophilic plants: Miscanthus and maize.
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Affiliation(s)
- Anna Bilska-Kos
- Department of Plant Biochemistry and Physiology, Plant Breeding and Acclimatization Institute - National Research Institute, Radzików, 05-870, Błonie, Poland; Department of Plant Physiology, Faculty of Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland.
| | - Piotr Panek
- Department of Plant Physiology, Faculty of Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland
| | - Anna Szulc-Głaz
- Department of Plant Physiology, Faculty of Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland
| | - Piotr Ochodzki
- Department of Plant Pathology, Plant Breeding and Acclimatization Institute - National Research Institute, Radzików, 05-870, Błonie, Poland
| | - Aneta Cisło
- Department of Plant Physiology, Faculty of Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland
| | - Jacek Zebrowski
- Department of Plant Physiology, Faculty of Biotechnology, University of Rzeszow, Aleja Rejtana 16c, 35-959, Rzeszow, Poland
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35
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Alonso-Cantabrana H, Cousins AB, Danila F, Ryan T, Sharwood RE, von Caemmerer S, Furbank RT. Diffusion of CO 2 across the Mesophyll-Bundle Sheath Cell Interface in a C 4 Plant with Genetically Reduced PEP Carboxylase Activity. PLANT PHYSIOLOGY 2018; 178:72-81. [PMID: 30018172 PMCID: PMC6130029 DOI: 10.1104/pp.18.00618] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 07/10/2018] [Indexed: 05/22/2023]
Abstract
Phosphoenolpyruvate carboxylase (PEPC), localized to the cytosol of the mesophyll cell, catalyzes the first carboxylation step of the C4 photosynthetic pathway. Here, we used RNA interference to target the cytosolic photosynthetic PEPC isoform in Setaria viridis and isolated independent transformants with very low PEPC activities. These plants required high ambient CO2 concentrations for growth, consistent with the essential role of PEPC in C4 photosynthesis. The combination of estimating direct CO2 fixation by the bundle sheath using gas-exchange measurements and modeling C4 photosynthesis with low PEPC activity allowed the calculation of bundle sheath conductance to CO2 diffusion (gbs ) in the progeny of these plants. Measurements made at a range of temperatures suggested no or negligible effect of temperature on gbs depending on the technique used to calculate gbs Anatomical measurements revealed that plants with reduced PEPC activity had reduced cell wall thickness and increased plasmodesmata (PD) density at the mesophyll-bundle sheath (M-BS) cell interface, whereas we observed little difference in these parameters at the mesophyll-mesophyll cell interface. The increased PD density at the M-BS interface was largely driven by an increase in the number of PD pit fields (cluster of PDs) rather than an increase in PD per pit field or the size of pit fields. The correlation of gbs with bundle sheath surface area per leaf area and PD area per M-BS area showed that these parameters and cell wall thickness are important determinants of gbs It is intriguing to speculate that PD development is responsive to changes in C4 photosynthetic flux.
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Affiliation(s)
- Hugo Alonso-Cantabrana
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington 99164-4236
| | - Florence Danila
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Timothy Ryan
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Robert E Sharwood
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 2601, Australia
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Sonawane BV, Sharwood RE, Whitney S, Ghannoum O. Shade compromises the photosynthetic efficiency of NADP-ME less than that of PEP-CK and NAD-ME C4 grasses. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3053-3068. [PMID: 29659931 PMCID: PMC5972597 DOI: 10.1093/jxb/ery129] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 03/19/2018] [Indexed: 05/18/2023]
Abstract
The high energy cost and apparently low plasticity of C4 photosynthesis compared with C3 photosynthesis may limit the productivity and distribution of C4 plants in low light (LL) environments. C4 photosynthesis evolved numerous times, but it remains unclear how different biochemical subtypes perform under LL. We grew eight C4 grasses belonging to three biochemical subtypes [NADP-malic enzyme (NADP-ME), NAD-malic enzyme (NAD-ME), and phosphoenolpyruvate carboxykinase (PEP-CK)] under shade (16% sunlight) or control (full sunlight) conditions and measured their photosynthetic characteristics at both low and high light. We show for the first time that LL (during measurement or growth) compromised the CO2-concentrating mechanism (CCM) to a greater extent in NAD-ME than in PEP-CK or NADP-ME C4 grasses by virtue of a greater increase in carbon isotope discrimination (∆P) and bundle sheath CO2 leakiness (ϕ), and a greater reduction in photosynthetic quantum yield (Φmax). These responses were partly explained by changes in the ratios of phosphoenolpyruvate carboxylase (PEPC)/initial Rubisco activity and dark respiration/photosynthesis (Rd/A). Shade induced a greater photosynthetic acclimation in NAD-ME than in NADP-ME and PEP-CK species due to a greater Rubisco deactivation. Shade also reduced plant dry mass to a greater extent in NAD-ME and PEP-CK relative to NADP-ME grasses. In conclusion, LL compromised the co-ordination of the C4 and C3 cycles and, hence, the efficiency of the CCM to a greater extent in NAD-ME than in PEP-CK species, while CCM efficiency was less impacted by LL in NADP-ME species. Consequently, NADP-ME species are more efficient at LL, which could explain their agronomic and ecological dominance relative to other C4 grasses.
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Affiliation(s)
- Balasaheb V Sonawane
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, NSW, Australia
- School of Biological Sciences, Washington State University, Pullman, WA, USA
- Correspondence:
| | - Robert E Sharwood
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Spencer Whitney
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra, ACT, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, NSW, Australia
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Kolbe AR, Cousins AB. Mesophyll conductance in Zea mays responds transiently to CO 2 availability: implications for transpiration efficiency in C 4 crops. THE NEW PHYTOLOGIST 2018; 217:1463-1474. [PMID: 29220090 DOI: 10.1111/nph.14942] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 11/07/2017] [Indexed: 06/07/2023]
Abstract
Mesophyll conductance (gm ) describes the movement of CO2 from the intercellular air spaces below the stomata to the site of initial carboxylation in the mesophyll. In contrast with C3 -gm , little is currently known about the intraspecific variation in C4 -gm or its responsiveness to environmental stimuli. To address these questions, gm was measured on five maize (Zea mays) lines in response to CO2 , employing three different estimates of gm . Each of the methods indicated a significant response of gm to CO2 . Estimates of gm were similar between methods at ambient and higher CO2 , but diverged significantly at low partial pressures of CO2 . These differences are probably driven by incomplete chemical and isotopic equilibrium between CO2 and bicarbonate under these conditions. Carbonic anhydrase and phosphoenolpyruvate carboxylase in vitro activity varied significantly despite similar values of gm and leaf anatomical traits. These results provide strong support for a CO2 response of gm in Z. mays, and indicate that gm in maize is probably driven by anatomical constraints rather than by biochemical limitations. The CO2 response of gm indicates a potential role for facilitated diffusion in C4 -gm . These results also suggest that water-use efficiency could be enhanced in C4 species by targeting gm .
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Affiliation(s)
- Allison R Kolbe
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
| | - Asaph B Cousins
- School of Biological Sciences, Washington State University, Pullman, WA, 99164, USA
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Danila FR, Quick WP, White RG, Kelly S, von Caemmerer S, Furbank RT. Multiple mechanisms for enhanced plasmodesmata density in disparate subtypes of C4 grasses. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1135-1145. [PMID: 29300922 PMCID: PMC6018992 DOI: 10.1093/jxb/erx456] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/30/2017] [Indexed: 05/25/2023]
Abstract
Proliferation of plasmodesmata (PD) connections between bundle sheath (BS) and mesophyll (M) cells has been proposed as a key step in the evolution of two-cell C4 photosynthesis; However, a lack of quantitative data has hampered further exploration and validation of this hypothesis. In this study, we quantified leaf anatomical traits associated with metabolite transport in 18 species of BEP and PACMAD grasses encompassing four origins of C4 photosynthesis and all three C4 subtypes (NADP-ME, NAD-ME, and PCK). We demonstrate that C4 leaves have greater PD density between M and BS cells than C3 leaves. We show that this greater PD density is achieved by increasing either the pit field (cluster of PD) area or the number of PD per pit field area. NAD-ME species had greater pit field area per M-BS interface than NADP-ME or PCK species. In contrast, NADP-ME and PCK species had lower pit field area with increased number of PD per pit field area than NAD-ME species. Overall, PD density per M-BS cell interface was greatest in NAD-ME species while PD density in PCK species exhibited the largest variability. Finally, the only other anatomical characteristic that clearly distinguished C4 from C3 species was their greater Sb value, the BS surface area to subtending leaf area ratio. In contrast, BS cell volume was comparable between the C3 and C4 grass species examined.
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Affiliation(s)
- Florence R Danila
- Research School of Biology, Australian National University, Canberra Australian Capital Territory, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra Australian Capital Territory, Australia
| | - William Paul Quick
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra Australian Capital Territory, Australia
- International Rice Research Institute, Los Baños, Laguna, Philippines
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Rosemary G White
- CSIRO Agriculture, Canberra Australian Capital Territory, Australia
| | - Steven Kelly
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Susanne von Caemmerer
- Research School of Biology, Australian National University, Canberra Australian Capital Territory, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra Australian Capital Territory, Australia
| | - Robert T Furbank
- Research School of Biology, Australian National University, Canberra Australian Capital Territory, Australia
- ARC Centre of Excellence for Translational Photosynthesis, Australian National University, Canberra Australian Capital Territory, Australia
- CSIRO Agriculture, Canberra Australian Capital Territory, Australia
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Ubierna N, Gandin A, Cousins AB. The response of mesophyll conductance to short-term variation in CO2 in the C4 plants Setaria viridis and Zea mays. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:1159-1170. [PMID: 29474683 PMCID: PMC6018935 DOI: 10.1093/jxb/erx464] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Accepted: 01/10/2018] [Indexed: 05/13/2023]
Abstract
Mesophyll conductance (gm) limits rates of C3 photosynthesis but little is known about its role in C4 photosynthesis. If gm were to limit C4 photosynthesis, it would likely be at low CO2 concentrations (pCO2). However, data on C4-gm across ranges of pCO2 are scarce. We describe the response of C4-gm to short-term variation in pCO2, at three temperatures in Setaria viridis, and at 25 °C in Zea mays. Additionally, we quantified the effect of finite gm calculations of leakiness (ϕ) and the potential limitations to photosynthesis imposed by stomata, mesophyll, and carbonic anhydrase (CA) across pCO2. In both species, gm increased with decreasing pCO2. Including a finite gm resulted in either no change or increased ϕ compared with values calculated with infinite gm depending on whether the observed 13C discrimination was high (Setaria) or low (Zea). Post-transitional regulation of the maximal PEP carboxylation rate and PEP regeneration limitation could influence estimates of gm and ϕ. At pCO2 below ambient, the photosynthetic rate was limited by CO2 availability. In this case, the limitation imposed by the mesophyll was similar or slightly lower than stomata limitation. At very low pCO2, CA further constrained photosynthesis. High gm could increase CO2 assimilation at low pCO2 and improve photosynthetic efficiency under situations when CO2 is limited, such as drought.
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Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington, USA
| | - Anthony Gandin
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington, USA
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, Washington, USA
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40
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Slattery RA, Walker BJ, Weber APM, Ort DR. The Impacts of Fluctuating Light on Crop Performance. PLANT PHYSIOLOGY 2018; 176:990-1003. [PMID: 29192028 PMCID: PMC5813574 DOI: 10.1104/pp.17.01234] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 11/27/2017] [Indexed: 05/18/2023]
Abstract
Rapidly changing light conditions can reduce carbon gain and productivity in field crops because photosynthetic responses to light fluctuations are not instantaneous. Plant responses to fluctuating light occur across levels of organizational complexity from entire canopies to the biochemistry of a single reaction and across orders of magnitude of time. Although light availability and variation at the top of the canopy are largely dependent on the solar angle and degree of cloudiness, lower crop canopies rely more heavily on light in the form of sunflecks, the quantity of which depends mostly on canopy structure but also may be affected by wind. The ability of leaf photosynthesis to respond rapidly to these variations in light intensity is restricted by the relatively slow opening/closing of stomata, activation/deactivation of C3 cycle enzymes, and up-regulation/down-regulation of photoprotective processes. The metabolic complexity of C4 photosynthesis creates the apparently contradictory possibilities that C4 photosynthesis may be both more and less resilient than C3 to dynamic light regimes, depending on the frequency at which these light fluctuations occur. We review the current understanding of the underlying mechanisms of these limitations to photosynthesis in fluctuating light that have shown promise in improving the response times of photosynthesis-related processes to changes in light intensity.
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Affiliation(s)
- Rebecca A Slattery
- Global Change and Photosynthesis Research Unit, Agricultural Research Service, United States Department of Agriculture, Urbana, Illinois 61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
| | - Berkley J Walker
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich-Heine-University, Duesseldorf, Germany 40225
| | - Andreas P M Weber
- Institute of Plant Biochemistry, Cluster of Excellence on Plant Sciences, Heinrich-Heine-University, Duesseldorf, Germany 40225
| | - Donald R Ort
- Global Change and Photosynthesis Research Unit, Agricultural Research Service, United States Department of Agriculture, Urbana, Illinois 61801
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois 61801
- Department of Plant Biology, University of Illinois, Urbana, Illinois 61801
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41
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Ubierna N, Holloway-Phillips MM, Farquhar GD. Using Stable Carbon Isotopes to Study C 3 and C 4 Photosynthesis: Models and Calculations. Methods Mol Biol 2018; 1770:155-196. [PMID: 29978402 DOI: 10.1007/978-1-4939-7786-4_10] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Stable carbon isotopes are a powerful tool to study photosynthesis. Initial applications consisted of determining isotope ratios of plant biomass using mass spectrometry. Subsequently, theoretical models relating C-isotope values to gas exchange characteristics were introduced and tested against instantaneous online measurements of 13C photosynthetic discrimination. Beginning in the twenty-first century, tunable diode laser spectroscopes with sufficient precision for determining isotope mixing ratios became commercially available. This has allowed collection of large data sets, at low cost and with unprecedented temporal resolution. With more data and accompanying knowledge, it has become apparent that there is a need for increased complexity in models and calculations. This chapter describes instantaneous online measurements of 13C photosynthetic discrimination, provides recommendations for experimental setup, and presents a thorough compilation of equations needed for different applications.
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Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, USA.
| | | | - Graham D Farquhar
- Research School of Biology, Australian National University, Canberra, ACT, Australia
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42
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Sonawane BV, Sharwood RE, von Caemmerer S, Whitney SM, Ghannoum O. Short-term thermal photosynthetic responses of C4 grasses are independent of the biochemical subtype. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5583-5597. [PMID: 29045727 PMCID: PMC5853683 DOI: 10.1093/jxb/erx350] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/14/2017] [Indexed: 05/20/2023]
Abstract
C4 photosynthesis evolved independently many times, resulting in multiple biochemical pathways; however, little is known about how these different pathways respond to temperature. We investigated the photosynthetic responses of eight C4 grasses belonging to three biochemical subtypes (NADP-ME, PEP-CK, and NAD-ME) to four leaf temperatures (18, 25, 32, and 40 °C). We also explored whether the biochemical subtype influences the thermal responses of (i) in vitro PEPC (Vpmax) and Rubisco (Vcmax) maximal activities, (ii) initial slope (IS) and CO2-saturated rate (CSR) derived from the A-Ci curves, and (iii) CO2 leakage out of the bundle sheath estimated from carbon isotope discrimination. We focussed on leakiness and the two carboxylases because they determine the coordination of the CO2-concentrating mechanism and are important for parameterizing the semi-mechanistic C4 photosynthesis model. We found that the thermal responses of Vpmax and Vcmax, IS, CSR, and leakiness varied among the C4 species independently of the biochemical subtype. No correlation was observed between Vpmax and IS or between Vcmax and CSR; while the ratios Vpmax/Vcmax and IS/CSR did not correlate with leakiness among the C4 grasses. Determining mesophyll and bundle sheath conductances in diverse C4 grasses is required to further elucidate how C4 photosynthesis responds to temperature.
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Affiliation(s)
- Balasaheb V Sonawane
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW, Australia
| | - Robert E Sharwood
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Susanne von Caemmerer
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Spencer M Whitney
- ARC Centre of Excellence for Translational Photosynthesis and Research School of Biology, Australian National University, Canberra ACT, Australia
| | - Oula Ghannoum
- ARC Centre of Excellence for Translational Photosynthesis and Hawkesbury Institute for the Environment, Western Sydney University, Richmond NSW, Australia
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Rizal G, Karki S, Thakur V, Wanchana S, Alonso-Cantabrana H, Dionora J, Sheehy JE, Furbank R, von Caemmerer S, Quick WP. A sorghum (Sorghum bicolor) mutant with altered carbon isotope ratio. PLoS One 2017. [PMID: 28640841 PMCID: PMC5480886 DOI: 10.1371/journal.pone.0179567] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Recent efforts to engineer C4 photosynthetic traits into C3 plants such as rice demand an understanding of the genetic elements that enable C4 plants to outperform C3 plants. As a part of the C4 Rice Consortium’s efforts to identify genes needed to support C4 photosynthesis, EMS mutagenized sorghum populations were generated and screened to identify genes that cause a loss of C4 function. Stable carbon isotope ratio (δ13C) of leaf dry matter has been used to distinguishspecies with C3 and C4 photosynthetic pathways. Here, we report the identification of a sorghum (Sorghum bicolor) mutant with a low δ13C characteristic. A mutant (named Mut33) with a pale phenotype and stunted growth was identified from an EMS treated sorghum M2 population. The stable carbon isotope analysis of the mutants showed a decrease of 13C uptake capacity. The noise of random mutation was reduced by crossing the mutant and its wildtype (WT). The back-cross (BC1F1) progenies were like the WT parent in terms of 13C values and plant phenotypes. All the BC1F2 plants with low δ13C died before they produced their 6th leaf. Gas exchange measurements of the low δ13C sorghum mutants showed a higher CO2 compensation point (25.24 μmol CO2.mol-1air) and the maximum rate of photosynthesis was less than 5μmol.m-2.s-1. To identify the genetic determinant of this trait, four DNA pools were isolated; two each from normal and low δ13C BC1F2 mutant plants. These were sequenced using an Illumina platform. Comparison of allele frequency of the single nucleotide polymorphisms (SNPs) between the pools with contrasting phenotype showed that a locus in Chromosome 10 between 57,941,104 and 59,985,708 bps had an allele frequency of 1. There were 211 mutations and 37 genes in the locus, out of which mutations in 9 genes showed non-synonymous changes. This finding is expected to contribute to future research on the identification of the causal factor differentiating C4 from C3 species that can be used in the transformation of C3 to C4 plants.
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Affiliation(s)
- Govinda Rizal
- C4 Rice Center, IRRI, Los Banos, Laguna, the Philippines
| | - Shanta Karki
- C4 Rice Center, IRRI, Los Banos, Laguna, the Philippines
- Government of Nepal, Ministry of Agricultural Development, Kathmandu, Nepal
| | - Vivek Thakur
- C4 Rice Center, IRRI, Los Banos, Laguna, the Philippines
- International Crops Research Institute for the Semi-Arid Tropics, Hyderabad, India
| | | | - Hugo Alonso-Cantabrana
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Jacque Dionora
- C4 Rice Center, IRRI, Los Banos, Laguna, the Philippines
| | - John E. Sheehy
- C4 Rice Center, IRRI, Los Banos, Laguna, the Philippines
- University of Sheffield, Sheffield, United Kingdom
| | - Robert Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT, Australia
| | - William Paul Quick
- C4 Rice Center, IRRI, Los Banos, Laguna, the Philippines
- University of Sheffield, Sheffield, United Kingdom
- * E-mail:
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Ubierna N, Gandin A, Boyd RA, Cousins AB. Temperature response of mesophyll conductance in three C 4 species calculated with two methods: 18 O discrimination and in vitro V pmax. THE NEW PHYTOLOGIST 2017; 214:66-80. [PMID: 27918624 DOI: 10.1111/nph.14359] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/27/2016] [Indexed: 05/08/2023]
Abstract
Mesophyll conductance (gm ) is an important factor limiting rates of C3 photosynthesis. However, its role in C4 photosynthesis is poorly understood because it has been historically difficult to estimate. We use two methods to derive the temperature responses of gm in C4 species. The first (Δ18 O) combines measurements of gas exchange with models and measurements of 18 O discrimination. The second method (in vitro Vpmax ) derives gm by retrofitting models of C4 photosynthesis and 13 C discrimination with gas exchange, kinetic constants and in vitro Vpmax measurements. The two methods produced similar gm for Setaria viridis and Zea mays. Additionally, we present the first temperature response (10-40°C) of C4 gm in S. viridis, Z. mays and Miscanthus × giganteus. Values for gm at 25°C ranged from 2.90 to 7.85 μmol m-2 s-1 Pa-1 . Our study demonstrated that: the two described methods are suitable to calculate gm in C4 species; gm values in C4 are similar to high-end values reported for C3 species; and gm increases with temperature analogous to reports for C3 species and the response is species specific. These results improve our mechanistic understanding of C4 photosynthesis.
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Affiliation(s)
- Nerea Ubierna
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Anthony Gandin
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Ryan A Boyd
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
| | - Asaph B Cousins
- School of Biological Sciences, Molecular Plant Sciences, Washington State University, Pullman, WA, 99164-4236, USA
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Sui X, Shan N, Hu L, Zhang C, Yu C, Ren H, Turgeon R, Zhang Z. The complex character of photosynthesis in cucumber fruit. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:1625-1637. [PMID: 28369547 PMCID: PMC5441898 DOI: 10.1093/jxb/erx034] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The surface area of a mature green cucumber (Cucumis sativa L.) fruit is comparable with that of a functional leaf, but the characteristics of fruit photosynthesis and its contribution to growth are poorly understood. Here, the photosynthetic properties of two genotypes of cucumber (dark green and light green fruits) were studied using a combination of electron microscopy, immunogold enzyme localization, chlorophyll fluorescence imaging, isotope tracer, and fruit darkening techniques. Chlorophyll content of the exocarp is similar to that of leaves, but there are no distinctive palisade and spongy tissues. The efficiency of PSII is similar to that in leaves, but with lower non-photochemical quenching (NPQ). Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is found mainly in the exocarp, while phosphoenolpyruvate carboxylase (PEPC) is primarily localized to vascular bundles and placenta tissue. Rubisco and PEPC expression at both transcriptional and translational levels increases concurrently during fruit growth. The contribution of fruit photosynthesis in exocarp to its own C accumulation is 9.4%, while ~88% of respiratory CO2 in fruit was captured and re-fixed. Photosynthesis by cucumber fruits, through direct fixation of atmospheric CO2 and recapture of respired CO2, as verified by 14CO2 uptake and gas exchange, makes an important contribution to fruit growth.
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Affiliation(s)
- Xiaolei Sui
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Nan Shan
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Liping Hu
- Beijing Vegetable Research Center, Beijing Academy of Agriculture and Forestry Sciences, Beijing 100097, China
| | - Cankui Zhang
- Department of Agronomy, Purdue University, West Lafayette, IN 47907, USA
| | - Changqing Yu
- Ecological Laboratory, Ecotech Ecological Technology Ltd, Beijing 100190, China
| | - Huazhong Ren
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing 100193, China
| | - Robert Turgeon
- Plant Biology Section, Cornell University, Ithaca, NY 14853, USA
| | - Zhenxian Zhang
- Beijing Key Laboratory of Growth and Developmental Regulation for Protected Vegetable Crops, College of Horticulture, China Agricultural University, Beijing 100193, China
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46
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Romanowska E, Buczyńska A, Wasilewska W, Krupnik T, Drożak A, Rogowski P, Parys E, Zienkiewicz M. Differences in photosynthetic responses of NADP-ME type C4 species to high light. PLANTA 2017; 245:641-657. [PMID: 27990574 PMCID: PMC5310562 DOI: 10.1007/s00425-016-2632-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 09/20/2016] [Indexed: 05/22/2023]
Abstract
MAIN CONCLUSION Three species chosen as representatives of NADP-ME C4 subtype exhibit different sensitivity toward photoinhibition, and great photochemical differences were found to exist between the species. These characteristics might be due to the imbalance in the excitation energy between the photosystems present in M and BS cells, and also due to that between species caused by the penetration of light inside the leaves. Such regulation in the distribution of light intensity between M and BS cells shows that co-operation between both the metabolic systems determines effective photosynthesis and reduces the harmful effects of high light on the degradation of PSII through the production of reactive oxygen species (ROS). We have investigated several physiological parameters of NADP-ME-type C4 species (e.g., Zea mays, Echinochloa crus-galli, and Digitaria sanguinalis) grown under moderate light intensity (200 µmol photons m-2 s-1) and, subsequently, exposed to excess light intensity (HL, 1600 µmol photons m-2 s-1). Our main interest was to understand why these species, grown under identical conditions, differ in their responses toward high light, and what is the physiological significance of these differences. Among the investigated species, Echinochloa crus-galli is best adapted to HL treatment. High resistance of the photosynthetic apparatus of E. crus-galli to HL was accompanied by an elevated level of phosphorylation of PSII proteins, and higher values of photochemical quenching, ATP/ADP ratio, activity of PSI and PSII complexes, as well as integrity of the thylakoid membranes. It was also shown that the non-radiative dissipation of energy in the studied plants was not dependent on carotenoid contents and, thus, other photoprotective mechanisms might have been engaged under HL stress conditions. The activity of the enzymes superoxide dismutase and ascorbate peroxidase as well as the content of malondialdehyde and H2O2 suggests that antioxidant defense is not responsible for the differences observed in the tolerance of NADP-ME species toward HL stress. We concluded that the chloroplasts of the examined NADP-ME species showed different sensitivity to short-term high light irradiance, suggesting a role of other factors excluding light factors, thus influencing the response of thylakoid proteins. We also observed that HL affects the mesophyll chloroplasts first hand and, subsequently, the bundle sheath chloroplasts.
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Affiliation(s)
- Elżbieta Romanowska
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland.
| | - Alicja Buczyńska
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Wioleta Wasilewska
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Tomasz Krupnik
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Anna Drożak
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Paweł Rogowski
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Eugeniusz Parys
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Maksymilian Zienkiewicz
- Department of Molecular Plant Physiology, Faculty of BiologyUniversity of Warsaw, Miecznikowa 1, 02-096, Warsaw, Poland
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Ma JY, Sun W, Koteyeva NK, Voznesenskaya E, Stutz SS, Gandin A, Smith-Moritz AM, Heazlewood JL, Cousins AB. Influence of light and nitrogen on the photosynthetic efficiency in the C 4 plant Miscanthus × giganteus. PHOTOSYNTHESIS RESEARCH 2017; 131:1-13. [PMID: 27531584 DOI: 10.1007/s11120-016-0281-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Accepted: 05/26/2016] [Indexed: 06/06/2023]
Abstract
There are numerous studies describing how growth conditions influence the efficiency of C4 photosynthesis. However, it remains unclear how changes in the biochemical capacity versus leaf anatomy drives this acclimation. Therefore, the aim of this study was to determine how growth light and nitrogen availability influence leaf anatomy, biochemistry and the efficiency of the CO2 concentrating mechanism in Miscanthus × giganteus. There was an increase in the mesophyll cell wall surface area but not cell well thickness in the high-light (HL) compared to the low-light (LL) grown plants suggesting a higher mesophyll conductance in the HL plants, which also had greater photosynthetic capacity. Additionally, the HL plants had greater surface area and thickness of bundle-sheath cell walls compared to LL plants, suggesting limited differences in bundle-sheath CO2 conductance because the increased area was offset by thicker cell walls. The gas exchange estimates of phosphoenolpyruvate carboxylase (PEPc) activity were significantly less than the in vitro PEPc activity, suggesting limited substrate availability in the leaf due to low mesophyll CO2 conductance. Finally, leakiness was similar across all growth conditions and generally did not change under the different measurement light conditions. However, differences in the stable isotope composition of leaf material did not correlate with leakiness indicating that dry matter isotope measurements are not a good proxy for leakiness. Taken together, these data suggest that the CO2 concentrating mechanism in Miscanthus is robust under low-light and limited nitrogen growth conditions, and that the observed changes in leaf anatomy and biochemistry likely help to maintain this efficiency.
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Affiliation(s)
- Jian-Ying Ma
- Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, 830011, China
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
| | - Wei Sun
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
- Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University, Changchun, 130024, China
| | - Nuria K Koteyeva
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Elena Voznesenskaya
- Laboratory of Anatomy and Morphology, V.L. Komarov Botanical Institute of the Russian Academy of Sciences, St. Petersburg, Russia
| | - Samantha S Stutz
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
| | - Anthony Gandin
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA
| | - Andreia M Smith-Moritz
- Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Joshua L Heazlewood
- Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
- ARC Centre of Excellence in Plant Cell Walls, School of BioSciences, The University of Melbourne, Melbourne, VIC, 3010, Australia
| | - Asaph B Cousins
- School of Biological Science, Washington State University, Pullman, WA, 99163, USA.
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48
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Osborn HL, Alonso-Cantabrana H, Sharwood RE, Covshoff S, Evans JR, Furbank RT, von Caemmerer S. Effects of reduced carbonic anhydrase activity on CO2 assimilation rates in Setaria viridis: a transgenic analysis. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:299-310. [PMID: 27702996 PMCID: PMC5853810 DOI: 10.1093/jxb/erw357] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/05/2016] [Indexed: 05/22/2023]
Abstract
In C4 species, the major β-carbonic anhydrase (β-CA) localized in the mesophyll cytosol catalyses the hydration of CO2 to HCO3-, which phosphoenolpyruvate carboxylase uses in the first step of C4 photosynthesis. To address the role of CA in C4 photosynthesis, we generated transgenic Setaria viridis depleted in β-CA. Independent lines were identified with as little as 13% of wild-type CA. No photosynthetic defect was observed in the transformed lines at ambient CO2 partial pressure (pCO2). At low pCO2, a strong correlation between CO2 assimilation rates and CA hydration rates was observed. C18O16O isotope discrimination was used to estimate the mesophyll conductance to CO2 diffusion from the intercellular air space to the mesophyll cytosol (gm) in control plants, which allowed us to calculate CA activities in the mesophyll cytosol (Cm). This revealed a strong relationship between the initial slope of the response of the CO2 assimilation rate to cytosolic pCO2 (ACm) and cytosolic CA activity. However, the relationship between the initial slope of the response of CO2 assimilation to intercellular pCO2 (ACi) and cytosolic CA activity was curvilinear. This indicated that in S. viridis, mesophyll conductance may be a contributing limiting factor alongside CA activity to CO2 assimilation rates at low pCO2.
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Affiliation(s)
- Hannah L Osborn
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Hugo Alonso-Cantabrana
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Robert E Sharwood
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Sarah Covshoff
- Department of Plant Sciences, University of Cambridge, Cambridge CB2 3EA, UK
| | - John R Evans
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Robert T Furbank
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Susanne von Caemmerer
- Australian Research Council Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
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49
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Gong XY, Schäufele R, Schnyder H. Bundle-sheath leakiness and intrinsic water use efficiency of a perennial C4 grass are increased at high vapour pressure deficit during growth. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:321-333. [PMID: 27864539 PMCID: PMC5853292 DOI: 10.1093/jxb/erw417] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/20/2016] [Indexed: 05/05/2023]
Abstract
Bundle-sheath leakiness (ϕ) is a key parameter of the CO2-concentrating mechanism of C4 photosynthesis and is related to leaf-level intrinsic water use efficiency (WUEi). This work studied short-term dynamic responses of ϕ to alterations of atmospheric CO2 concentration in Cleistogenes squarrosa, a perennial grass, grown at high (1.6 kPa) or low (0.6 kPa) vapour pressure deficit (VPD) combined with high or low N supply in controlled environment experiments. ϕ was determined by concurrent measurements of photosynthetic gas exchange and on-line carbon isotope discrimination, using a new protocol. Growth at high VPD led to an increase of ϕ by 0.13 and a concurrent increase of WUEi by 14%, with similar effects at both N levels. ϕ responded dynamically to intercellular CO2 concentration (C i), increasing with C i Across treatments, ϕ was negatively correlated to the ratio of CO2 saturated assimilation rate to carboxylation efficiency (a proxy of the relative activities of Rubisco and phosphoenolpyruvate carboxylase) indicating that the long-term environmental effect on ϕ was related to the balance between C3 and C4 cycles. Our study revealed considerable dynamic and long-term variation in ϕ of C. squarrosa, suggesting that ϕ should be determined when carbon isotope discrimination is used to assess WUEi Also, the data indicate a trade-off between WUEi and energetic efficiency in C. squarrosa.
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Affiliation(s)
- Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354 Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354 Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Technische Universität München, Alte Akademie 12, 85354 Freising, Germany
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50
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Retta M, Yin X, van der Putten PEL, Cantre D, Berghuijs HNC, Ho QT, Verboven P, Struik PC, Nicolaï BM. Impact of anatomical traits of maize (Zea mays L.) leaf as affected by nitrogen supply and leaf age on bundle sheath conductance. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 252:205-214. [PMID: 27717455 DOI: 10.1016/j.plantsci.2016.07.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Revised: 06/24/2016] [Accepted: 07/23/2016] [Indexed: 06/06/2023]
Abstract
The mechanism of photosynthesis in C4 crops depends on the archetypal Kranz-anatomy. To examine how the leaf anatomy, as altered by nitrogen supply and leaf age, affects the bundle sheath conductance (gbs), maize (Zea mays L.) plants were grown under three contrasting nitrogen levels. Combined gas exchange and chlorophyll fluorescence measurements were done on fully grown leaves at two leaf ages. The measured data were analysed using a biochemical model of C4 photosynthesis to estimate gbs. The leaf microstructure and ultrastructure were quantified using images obtained from micro-computed tomography and microscopy. There was a strong positive correlation between gbs and leaf nitrogen content (LNC) while old leaves had lower gbs than young leaves. Leaf thickness, bundle sheath cell wall thickness and surface area of bundle sheath cells per unit leaf area (Sb) correlated well with gbs although they were not significantly affected by LNC. As a result, the increase of gbs with LNC was little explained by the alteration of leaf anatomy. In contrast, the combined effect of LNC and leaf age on Sb was responsible for differences in gbs between young leaves and old leaves. Future investigations should consider changes at the level of plasmodesmata and membranes along the CO2 leakage pathway to unravel LNC and age effects further.
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Affiliation(s)
- Moges Retta
- BIOSYST-MeBioS, KU Leuven/Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium; Centre for Crop Systems Analysis, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands
| | - Xinyou Yin
- Centre for Crop Systems Analysis, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands; BioSolar Cells, P.O. Box 98, 6700 AB Wageningen, The Netherlands
| | - Peter E L van der Putten
- Centre for Crop Systems Analysis, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands; BioSolar Cells, P.O. Box 98, 6700 AB Wageningen, The Netherlands
| | - Denis Cantre
- BIOSYST-MeBioS, KU Leuven/Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Herman N C Berghuijs
- BIOSYST-MeBioS, KU Leuven/Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium; Centre for Crop Systems Analysis, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands; BioSolar Cells, P.O. Box 98, 6700 AB Wageningen, The Netherlands
| | - Quang Tri Ho
- BIOSYST-MeBioS, KU Leuven/Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Pieter Verboven
- BIOSYST-MeBioS, KU Leuven/Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium
| | - Paul C Struik
- Centre for Crop Systems Analysis, Wageningen University, P.O. Box 430, 6700 AK Wageningen, The Netherlands; BioSolar Cells, P.O. Box 98, 6700 AB Wageningen, The Netherlands
| | - Bart M Nicolaï
- BIOSYST-MeBioS, KU Leuven/Flanders Center of Postharvest Technology, Willem de Croylaan 42, B-3001 Leuven, Belgium.
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