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Cantrell M, Ware MA, Peers G. Characterizing compensatory mechanisms in the absence of photoprotective qE in Chlamydomonas reinhardtii. PHOTOSYNTHESIS RESEARCH 2023; 158:23-39. [PMID: 37488319 DOI: 10.1007/s11120-023-01037-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 06/26/2023] [Indexed: 07/26/2023]
Abstract
Rapid fluctuations in the quantity and quality of natural light expose photosynthetic organisms to conditions when the capacity to utilize absorbed quanta is insufficient. These conditions can result in the production of reactive oxygen species and photooxidative damage. Non-photochemical quenching (NPQ) and alternative electron transport are the two most prominent mechanisms which synergistically function to minimize the overreduction of photosystems. In the green alga Chlamydomonas reinhardtii, the stress-related light-harvesting complex (LHCSR) is a required component for the rapid induction and relaxation of NPQ in the light-harvesting antenna. Here, we use simultaneous chlorophyll fluorescence and oxygen exchange measurements to characterize the acclimation of the Chlamydomonas LHCSR-less mutant (npq4lhcsr1) to saturating light conditions. We demonstrate that, in the absence of NPQ, Chlamydomonas does not acclimate to sinusoidal light through increased light-dependent oxygen consumption. We also show that the npq4lhcsr1 mutant has an increased sink capacity downstream of PSI and this energy flow is likely facilitated by cyclic electron transport. Furthermore, we show that the timing of additions of mitochondrial inhibitors has a major influence on plastid/mitochondrial coupling experiments.
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Affiliation(s)
- Michael Cantrell
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Maxwell A Ware
- Department of Biology, Colorado State University, Fort Collins, CO, USA
| | - Graham Peers
- Department of Biology, Colorado State University, Fort Collins, CO, USA.
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2
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Beckett RP, Roach T, Minibayeva F, Werth S. Alternative electron transport pathways contribute to tolerance to high light stress in lichenized algae. PHYSIOLOGIA PLANTARUM 2023; 175:e13904. [PMID: 37002828 DOI: 10.1111/ppl.13904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/28/2023] [Accepted: 03/28/2023] [Indexed: 06/19/2023]
Abstract
The photosynthetic apparatus of lichen photobionts has been well-characterized by chlorophyll fluorescence analysis (e.g., by pulse amplitude modulation [PAM]), which provides a proxy of the activity of photosystem II (PSII) and its antenna. However, such kinetics are unable to directly characterize photosystem I (PSI) activity and the associated alternative electron pathways that may be involved in photoprotection. Instead, PSI can be probed in vivo by near-infrared absorption, measured at the same time as standard chlorophyll fluorescence (e.g., using the WALZ Dual PAM). Here, we used the Dual PAM to investigate cyclic electron flow and photoprotection in a range of mostly temperate lichens sampled from shaded to more open microhabitats. Sun species displayed lower acceptor side limitation of PSI (Y[NA]) early in illumination when compared to shade species, indicative of higher flavodiiron-mediated pseudocyclic electron flow. In response to high irradiance, some lichens accumulate melanin, and Y[NA] was lower and NAD(P)H dehydrogenase (NDH-2)-type cyclic flow was higher in melanised than pale forms. Furthermore, non-photochemical quenching (NPQ) was higher and faster relaxing in shade than sun species, while all lichens displayed high rates of photosynthetic cyclic electron flow. In conclusion, our data suggest that (1) low acceptor side limitation of PSI is important for sun-exposed lichens; (2) NPQ helps shade species tolerate brief exposure to high irradiance; and (3) cyclic electron flow is a prominent feature of lichens regardless of habitat, although NDH-2-type flow is associated with high light acclimation.
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Affiliation(s)
- Richard Peter Beckett
- School of Life Sciences, University of KwaZulu-Natal, Scottsville, South Africa
- Open Lab 'Biomarker', Kazan (Volga Region) Federal University, Kazan, Russia
| | - Thomas Roach
- Department of Botany, University of Innsbruck, Innsbruck, Austria
| | - Farida Minibayeva
- Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", Kazan, Russia
| | - Silke Werth
- Faculty of Biology Systematics, Biodiversity and Evolution of Plants, Ludwig-Maximilians-University, Munich, Germany
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3
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Obara A, Ogawa M, Oyama Y, Suzuki Y, Kono M. Effects of High Irradiance and Low Water Temperature on Photoinhibition and Repair of Photosystems in Marimo ( Aegagropila linnaei) in Lake Akan, Japan. Int J Mol Sci 2022; 24:ijms24010060. [PMID: 36613526 PMCID: PMC9820325 DOI: 10.3390/ijms24010060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 12/24/2022] Open
Abstract
The green alga Aegagropila linnaei often forms spherical aggregates called "marimo" in Lake Akan in Japan. In winter, marimo are exposed to low water temperatures at 1-4 °C but protected from strong sunlight by ice coverage, which may disappear due to global warming. In this study, photoinhibition in marimo was examined at 2 °C using chlorophyll fluorescence and 830 nm absorption. Filamentous cells of A. linnaei dissected from marimo were exposed to strong light at 2 °C. Photosystem II (PSII) was markedly photoinhibited, while photosystem I was unaffected. When the cells with PSII damaged by the 4 h treatment were subsequently illuminated with moderate repair light at 2 °C, the maximal efficiency of PSII was recovered to the level before photoinhibition. However, after the longer photoinhibitory treatments, PSII efficiency did not recover by the repair light. When the cells were exposed to simulated diurnal light for 12 h per day, which was more ecological, the cells died within a few days. Our results showed new findings of the PSII repair at 2 °C and serious damage at the cellular level from prolonged high-light treatments. Further, we provided a clue to what may happen to marimo in Lake Akan in the near future.
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Affiliation(s)
- Akina Obara
- Department of Biological Sciences, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Kanagawa, Hiratsuka 259-1293, Japan
| | - Mari Ogawa
- Department of Primary Education, Faculty of Education, Yasuda Women’s University, 6-13-1 Yasuhigashi, Asaminami-ku, Hiroshima 731-0153, Japan
| | - Yoichi Oyama
- Marimo Research Center, Kushiro Board of Education, Hokkaido, Kushiro 085-0467, Japan
| | - Yoshihiro Suzuki
- Department of Biological Sciences, Faculty of Science, Kanagawa University, 2946 Tsuchiya, Kanagawa, Hiratsuka 259-1293, Japan
| | - Masaru Kono
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo 113-0033, Japan
- Correspondence: ; Tel.: +81-3-5841-4467; Fax: +81-3-5841-4465
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4
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Couso I, Smythers AL, Ford MM, Umen JG, Crespo JL, Hicks LM. Inositol polyphosphates and target of rapamycin kinase signalling govern photosystem II protein phosphorylation and photosynthetic function under light stress in Chlamydomonas. THE NEW PHYTOLOGIST 2021; 232:2011-2025. [PMID: 34529857 DOI: 10.1111/nph.17741] [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: 08/15/2021] [Accepted: 09/09/2021] [Indexed: 05/28/2023]
Abstract
Stress and nutrient availability influence cell proliferation through complex intracellular signalling networks. In a previous study it was found that pyro-inositol polyphosphates (InsP7 and InsP8 ) produced by VIP1 kinase, and target of rapamycin (TOR) kinase signalling interacted synergistically to control cell growth and lipid metabolism in the green alga Chlamydomonas reinhardtii. However, the relationship between InsPs and TOR was not completely elucidated. We used an in vivo assay for TOR activity together with global proteomic and phosphoproteomic analyses to assess differences between wild-type and vip1-1 in the presence and absence of rapamycin. We found that TOR signalling is more severely affected by the inhibitor rapamycin in a vip1-1 mutant compared with wild-type, indicating that InsP7 and InsP8 produced by VIP1 act independently but also coordinately with TOR. Additionally, among hundreds of differentially phosphorylated peptides detected, an enrichment for photosynthesis-related proteins was observed, particularly photosystem II proteins. The significance of these results was underscored by the finding that vip1-1 strains show multiple defects in photosynthetic physiology that were exacerbated under high light conditions. These results suggest a novel role for inositol pyrophosphates and TOR signalling in coordinating photosystem phosphorylation patterns in Chlamydomonas cells in response to light stress and possibly other stresses.
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Affiliation(s)
- Inmaculada Couso
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Avda. Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Amanda L Smythers
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Megan M Ford
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - James G Umen
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - José L Crespo
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla, Avda. Américo Vespucio, 49, Sevilla, 41092, Spain
| | - Leslie M Hicks
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
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5
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Barera S, Dall'Osto L, Bassi R. Effect of lhcsr gene dosage on oxidative stress and light use efficiency by Chlamydomonas reinhardtii cultures. J Biotechnol 2021; 328:12-22. [PMID: 33434600 DOI: 10.1016/j.jbiotec.2020.12.023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/27/2020] [Accepted: 12/31/2020] [Indexed: 10/22/2022]
Abstract
Unicellular green algae, a promising source for renewable biofuels, produce lipid-rich biomass from light and CO2. Productivity in photo-bioreactors is affected by inhomogeneous light distribution from high cell pigment causing heat dissipation of light energy absorbed in excess and shading of the deep layers. Contrasting reports have been published on the relation between photoprotective energy dissipation and productivity. Here, we have re-investigated the relation between energy quenching (qE) activity, photodamage and light use efficiency by comparing WT and two Chlamydomonas reinhardtii strains differing for their complement in LHCSR proteins, which catalyse dissipation of excitation energy in excess (qE). Strains were analysed for ROS production, protein composition, rate of photodamage and productivity assessed under wide light and CO2 conditions. The strain lacking LHCSR1 and knocked down in LHCSR3, thus depleted in qE, produced O2 at significantly higher rate under high light, accompanied by enhanced singlet oxygen release and PSII photodamage. However, biomass productivity of WT was delayed in respect for mutant strains under intermittent light conditions only, implying that PSII activity was not the limiting factor under excess light. Contrary to previous proposals, domestication of Chlamydomonas for carbon assimilation rate in photo-bioreactors by down-regulation of photoprotective energy dissipation was ineffective in increasing algal biomass productivity.
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Affiliation(s)
- Simone Barera
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134, Verona, Italy.
| | - Luca Dall'Osto
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134, Verona, Italy.
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134, Verona, Italy.
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Ma M, Liu Y, Bai C, Yang Y, Sun Z, Liu X, Zhang S, Han X, Yong JWH. The Physiological Functionality of PGR5/PGRL1-Dependent Cyclic Electron Transport in Sustaining Photosynthesis. FRONTIERS IN PLANT SCIENCE 2021; 12:702196. [PMID: 34305990 PMCID: PMC8294387 DOI: 10.3389/fpls.2021.702196] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/07/2021] [Indexed: 05/07/2023]
Abstract
The cyclic electron transport (CET), after the linear electron transport (LET), is another important electron transport pathway during the light reactions of photosynthesis. The proton gradient regulation 5 (PGR5)/PRG5-like photosynthetic phenotype 1 (PGRL1) and the NADH dehydrogenase-like complex pathways are linked to the CET. Recently, the regulation of CET around photosystem I (PSI) has been recognized as crucial for photosynthesis and plant growth. Here, we summarized the main biochemical processes of the PGR5/PGRL1-dependent CET pathway and its physiological significance in protecting the photosystem II and PSI, ATP/NADPH ratio maintenance, and regulating the transitions between LET and CET in order to optimize photosynthesis when encountering unfavorable conditions. A better understanding of the PGR5/PGRL1-mediated CET during photosynthesis might provide novel strategies for improving crop yield in a world facing more extreme weather events with multiple stresses affecting the plants.
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Affiliation(s)
- Mingzhu Ma
- College of Land and Environment, National Key Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Northeast China Plant Nutrition and Fertilization Scientific Observation and Research Center for Ministry of Agriculture and Rural Affairs, Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, Shenyang Agricultural University, Shenyang, China
| | - Yifei Liu
- College of Land and Environment, National Key Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Northeast China Plant Nutrition and Fertilization Scientific Observation and Research Center for Ministry of Agriculture and Rural Affairs, Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, Shenyang Agricultural University, Shenyang, China
- The UWA Institute of Agriculture, The University of Western Australia, Perth, WA, Australia
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
- School of Agriculture and Environment, The University of Western Australia, Perth, WA, Australia
- *Correspondence: Yifei Liu, ; Xiaori Han,
| | - Chunming Bai
- National Sorghum Improvement Center, Liaoning Academy of Agricultural Sciences, Shenyang, China
| | - Yunhong Yang
- Professional Technology Innovation Center of Magnesium Nutrition, Yingkou Magnesite Chemical Ind Group Co., Ltd., Yingkou, China
| | - Zhiyu Sun
- College of Land and Environment, National Key Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Northeast China Plant Nutrition and Fertilization Scientific Observation and Research Center for Ministry of Agriculture and Rural Affairs, Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, Shenyang Agricultural University, Shenyang, China
| | - Xinyue Liu
- College of Land and Environment, National Key Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Northeast China Plant Nutrition and Fertilization Scientific Observation and Research Center for Ministry of Agriculture and Rural Affairs, Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, Shenyang Agricultural University, Shenyang, China
| | - Siwei Zhang
- College of Land and Environment, National Key Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Northeast China Plant Nutrition and Fertilization Scientific Observation and Research Center for Ministry of Agriculture and Rural Affairs, Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, Shenyang Agricultural University, Shenyang, China
| | - Xiaori Han
- College of Land and Environment, National Key Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources, Northeast China Plant Nutrition and Fertilization Scientific Observation and Research Center for Ministry of Agriculture and Rural Affairs, Key Laboratory of Protected Horticulture of Education Ministry and Liaoning Province, Shenyang Agricultural University, Shenyang, China
- *Correspondence: Yifei Liu, ; Xiaori Han,
| | - Jean Wan Hong Yong
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia
- Department of Biosystems and Technology, Swedish University of Agricultural Sciences, Alnarp, Sweden
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7
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Roach T. LHCSR3-Type NPQ Prevents Photoinhibition and Slowed Growth under Fluctuating Light in Chlamydomonas reinhardtii. PLANTS 2020; 9:plants9111604. [PMID: 33218177 PMCID: PMC7698959 DOI: 10.3390/plants9111604] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/05/2020] [Accepted: 11/16/2020] [Indexed: 01/14/2023]
Abstract
Natural light intensities can rise several orders of magnitude over subsecond time spans, posing a major challenge for photosynthesis. Fluctuating light tolerance in the green alga Chlamydomonas reinhardtii requires alternative electron pathways, but the role of nonphotochemical quenching (NPQ) is not known. Here, fluctuating light (10 min actinic light followed by 10 min darkness) led to significant increase in NPQ/qE-related proteins, LHCSR1 and LHCSR3, relative to constant light of the same subsaturating or saturating intensity. Elevated levels of LHCSR1/3 increased the ability of cells to safely dissipate excess light energy to heat (i.e., qE-type NPQ) during dark to light transition, as measured with chlorophyll fluorescence. The low qE phenotype of the npq4 mutant, which is unable to produce LHCSR3, was abolished under fluctuating light, showing that LHCSR1 alone enables very high levels of qE. Photosystem (PS) levels were also affected by light treatments; constant light led to lower PsbA levels and Fv/Fm values, while fluctuating light led to lower PsaA and maximum P700+ levels, indicating that constant and fluctuating light induced PSII and PSI photoinhibition, respectively. Under fluctuating light, npq4 suffered more PSI photoinhibition and significantly slower growth rates than parental wild type, whereas npq1 and npq2 mutants affected in xanthophyll carotenoid compositions had identical growth under fluctuating and constant light. Overall, LHCSR3 rather than total qE capacity or zeaxanthin is shown to be important in C. reinhardtii in tolerating fluctuating light, potentially via preventing PSI photoinhibition.
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Affiliation(s)
- Thomas Roach
- Department of Botany and Centre for Molecular Biosciences Innsbruck, University of Innsbruck, Sternwartestraße 15, 6020 Innsbruck, Austria
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8
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Girolomoni L, Bellamoli F, de la Cruz Valbuena G, Perozeni F, D'Andrea C, Cerullo G, Cazzaniga S, Ballottari M. Evolutionary divergence of photoprotection in the green algal lineage: a plant-like violaxanthin de-epoxidase enzyme activates the xanthophyll cycle in the green alga Chlorella vulgaris modulating photoprotection. THE NEW PHYTOLOGIST 2020; 228:136-150. [PMID: 32442330 PMCID: PMC7539987 DOI: 10.1111/nph.16674] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 05/13/2020] [Indexed: 05/05/2023]
Abstract
The xanthophyll cycle is the metabolic process by which the carotenoid violaxanthin is de-epoxidated to zeaxanthin, a xanthophyll with a crucial photoprotective role in higher plants and mosses. The role of zeaxanthin is still unclear in green algae, and a peculiar violaxanthin de-epoxidating enzyme was found in the model organism Chlamydomonas reinhardtii. Here, we investigated the molecular details and functions of the xanthophyll cycle in the case of Chlorella vulgaris, one of the green algae most considered for industrial cultivation, where resistance to high light stress is a prerequisite for sustainable biomass production. Identification of the violaxanthin de-epoxidase enzyme in C. vulgaris was performed by genome mining and in vitro analysis of the catalytic activity of the gene product identified. The photoprotective role of zeaxanthin was then investigated in vivo and in isolated pigment-binding complexes. The results obtained demonstrate the functioning, even though with a different pH sensitivity, of a plant-like violaxanthin de-epoxidase enzyme in C. vulgaris. Differently from C. reinhardtii, zeaxanthin accumulation in C. vulgaris was found to be crucial for photoprotective quenching of excitation energy harvested by both photosystem I and II. These findings demonstrate an evolutionary divergence of photoprotective mechanisms among Chlorophyta.
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Affiliation(s)
- Laura Girolomoni
- Department of BiotechnologyUniversity of VeronaStrada le Grazie 15Verona37134Italy
| | - Francesco Bellamoli
- Department of BiotechnologyUniversity of VeronaStrada le Grazie 15Verona37134Italy
| | | | - Federico Perozeni
- Department of BiotechnologyUniversity of VeronaStrada le Grazie 15Verona37134Italy
| | - Cosimo D'Andrea
- IFN‐CNRDepartment of PhysicsPolitecnico di MilanoPiazza Leonardo da Vinci 32Milan20133Italy
- Center for NanoScience and Technology @PoliMiIstituto Italiano di Tecnologiavia Pascoli 70/3Milan20133Italy
| | - Giulio Cerullo
- IFN‐CNRDepartment of PhysicsPolitecnico di MilanoPiazza Leonardo da Vinci 32Milan20133Italy
| | - Stefano Cazzaniga
- Department of BiotechnologyUniversity of VeronaStrada le Grazie 15Verona37134Italy
| | - Matteo Ballottari
- Department of BiotechnologyUniversity of VeronaStrada le Grazie 15Verona37134Italy
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9
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Zhang H, Xu Z, Guo K, Huo Y, He G, Sun H, Guan Y, Xu N, Yang W, Sun G. Toxic effects of heavy metal Cd and Zn on chlorophyll, carotenoid metabolism and photosynthetic function in tobacco leaves revealed by physiological and proteomics analysis. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 202:110856. [PMID: 32629202 DOI: 10.1016/j.ecoenv.2020.110856] [Citation(s) in RCA: 79] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 05/18/2023]
Abstract
To explore the mechanisms underlying the action of the heavy metals Cd and Zn on the photosynthetic function of plant leaves, the effects of 100 μmol L-1 Cd and 200 μmol L-1 Zn stress (the exposure concentrations of Cd and Zn in the culture medium were 2.24 mg kg-1 and 5.36 mg kg-1) on the chlorophyll and carotenoid contents as well as the photosynthetic function of tobacco leaves (Long Jiang 911) were studied. The key proteins in these physiological processes were quantitatively analyzed using a TMT-based proteomics approach. Cd stress was found to inhibit the expression of key enzymes during chlorophyll synthesis in leaves, resulting in a decrease of the Chl content. However, Zn stress did not significantly influence the chlorophyll content. Leaves adapted to Zn stress by upregulating CAO expression and increase the Chl b content. Although the Car content in leaves did not significantly change under either Cd or Zn stress, the expressions of ZE and VDE during Car metabolism decreased significantly under Cd stress. This was accompanied by damages to the xanthophyll cycle and the NPQ-dependent energy dissipation mechanism. In contrast, under Zn stress, leaves adapted to Zn stress by increasing the expression of VDE, thus improving NPQ. Under Cd stress, the expressions of three sets of proteins were significantly down-regulated, including PSII donor-side proteins (PPD3, PPD6, OEE1, OEE2-1, OEE2-2, OEE2-3, and OEE3-2), receptor-side proteins (D1, D2, CP43, CP47, Cyt b559α, Cyt b559β, PsbL, PsbQ, PsbR, Psb27-H1, and Psb28), and core proteins of the PSI reaction center (psaA, psaB, psaC, psaD, psaE-A, PsaE-B, psaF, psaG, psaH-1, psaK, psaL, psaN, and psaOL). In comparison, only eight of the above proteins (PPD6, OEE3-2, PsbL, PsbQ, Psb27-H1, psaL, and psaOL) were significantly down-regulated by Zn stress. Under Cd stress, both the donor side and the receptor side of PSII were damaged, and PSII and PSI experienced severe photoinhibition. However, Zn stress did not decrease either PSII or PSI activities in tobacco leaves. In addition, the expression of electron transport-related proteins (cytb6/f complex, PC, Fd, and FNR), ATPase subunits, Rubisco subunits, and RCA decreased significantly in leaves under Cd stress. However, no significant changes were observed in any of these proteins under Zn stress. Although Cd stress was found to up-regulate the expressions of PGRL1A and PGRL1B and induce an increase of PGR5/PGRL1-CEF in tobacco leaves, NDH-CEF was significantly inhibited. Under Zn stress, the expressions of ndhH and PGRL1A in leaves were significantly up-regulated, but there were no significant changes in either NDH-CEF or PGR5/PGRL-CEF. Under Cd stress, the expressions of proteins related to Fd-dependent nitrogen metabolism and reactive oxygen species (ROS) scavenging processes (e.g., FTR, Fd-NiR, and Fd-GOGAT) were significantly down-regulated in leaves. However, no significant changes of any of the above proteins were identified under Zn stress. In summary, Cd stress could inhibit the synthesis of chlorophyll in tobacco leaves, significantly down-regulate the expressions of photosynthesis-related proteins or subunits, and suppress both the xanthophyll cycle and NDH-CEF process. The expressions of proteins related to the Fd-dependent nitrogen metabolism and ROS scavenging were also significantly down-regulated, which blocked the photosynthetic electron transport, thus resulting in severe photoinhibition of both PSII and PSI. However, Zn stress had little effect on the photosynthetic function of tobacco leaves.
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Affiliation(s)
- Huihui Zhang
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China; Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China
| | - Zisong Xu
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Kaiwen Guo
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Yuze Huo
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Guoqiang He
- Mudanjiang Tobacco Science Research Institute, Mudanjiang, Heilongjiang, China
| | - Hongwei Sun
- Mudanjiang Tobacco Science Research Institute, Mudanjiang, Heilongjiang, China
| | - Yupeng Guan
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Nan Xu
- Natural Resources and Ecology Institute, Heilongjiang Sciences Academy, Harbin, Heilongjiang, China
| | - Wei Yang
- College of Resources and Environment, Northeast Agricultural University, Harbin, Heilongjiang, China.
| | - Guangyu Sun
- Key Laboratory of Saline-alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Sciences, Northeast Forestry University, Harbin, Heilongjiang, China.
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10
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Identification of the electron donor to flavodiiron proteins in Synechocystis sp. PCC 6803 by in vivo spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148256. [PMID: 32622739 DOI: 10.1016/j.bbabio.2020.148256] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 06/19/2020] [Accepted: 06/19/2020] [Indexed: 01/18/2023]
Abstract
Flavodiiron proteins (FDPs) of photosynthetic organisms play a photoprotective role by reducing oxygen to water and thus avoiding the accumulation of excess electrons on the photosystem I (PSI) acceptor side under stress conditions. In Synechocystis sp. PCC 6803 grown under high CO2, both FDPs Flv1 and Flv3 are indispensable for oxygen reduction. We performed a detailed in vivo kinetic study of wild-type (WT) and Δflv1/3 strains of Synechocystis using light-induced NADPH fluorescence and near-infrared absorption of iron-sulfur clusters from ferredoxin and the PSI acceptors (FAFB), collectively named FeS. These measurements were performed under conditions where the Calvin-Benson cycle is inactive or poorly activated. Under such conditions, the NADPH decay following a short illumination decays in parallel in both strains and exhibits a time lag which is correlated to the presence of reduced FeS. On the contrary, reduced FeS decays much faster in WT than in Δflv1/3 (13 vs 2 s-1). These data unambiguously show that reduced ferredoxin, or possibly reduced FAFB, is the direct electron donor to the Flv1/Flv3 heterodimer. Evidences for large reduction of (FAFB) and recombination reactions within PSI were also provided by near-infrared absorption. Mutants lacking either the NDH1-L complex, the homolog of complex I of respiration, or the Pgr5 protein show no difference with WT in the oxidation of reduced FeS following a short illumination. These observations question the participation of a significant cyclic electron flow in cyanobacteria during the first seconds of the induction phase of photosynthesis.
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Roach T, Na CS, Stöggl W, Krieger-Liszkay A. The non-photochemical quenching protein LHCSR3 prevents oxygen-dependent photoinhibition in Chlamydomonas reinhardtii. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:2650-2660. [PMID: 31943079 PMCID: PMC7210768 DOI: 10.1093/jxb/eraa022] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Accepted: 01/13/2020] [Indexed: 05/18/2023]
Abstract
Non-photochemical quenching (NPQ) helps dissipate surplus light energy, preventing formation of reactive oxygen species (ROS). In Chlamydomonas reinhardtii, the thylakoid membrane protein LHCSR3 is involved in pH-dependent (qE-type) NPQ, lacking in the npq4 mutant. Preventing PSII repair revealed that npq4 lost PSII activity faster than the wild type (WT) in elevated O2, while no difference between strains was observed in O2-depleted conditions. Low Fv/Fm values remained 1.5 h after moving cells out of high light, and this qH-type quenching was independent of LHCSR3 and not accompanied by losses of maximum PSII activity. Culturing cells in historic O2 atmospheres (30-35%) increased the qE of cells, due to increased LHCSR1 and PsbS levels, and LHCSR3 in the WT, showing that atmospheric O2 tensions regulate qE capacity. Colony growth of npq4 was severely restricted at elevated O2, and npq4 accumulated more reactive electrophile species (RES) than the WT, which could damage PSI. Levels of PsaA (PSI) were lower in npq4 grown at 35% O2, while PsbA (PSII) levels remained stable. We conclude that even at high O2 concentrations, the PSII repair cycle is sufficient to maintain net levels of PSII. However, LHCSR3 has an important function in protecting PSI against O2-mediated damage, such as via RES.
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Affiliation(s)
- Thomas Roach
- Department of Botany and Centre for Molecular Biology Innsbruck, Leopold-Franzens-Universität-Innsbruck, Sternwartestraße 15, Innsbruck, Austria
- Correspondence:
| | - Chae Sun Na
- Department of Botany and Centre for Molecular Biology Innsbruck, Leopold-Franzens-Universität-Innsbruck, Sternwartestraße 15, Innsbruck, Austria
- Seed Conservation Research Division, Department of Seed Vault, Baekdudaegan National Arboretum, Munsu-ro, Chunyang-myeon, Bonghwa-gun, Gyeongsangbuk-do, Republic of Korea
| | - Wolfgang Stöggl
- Department of Botany and Centre for Molecular Biology Innsbruck, Leopold-Franzens-Universität-Innsbruck, Sternwartestraße 15, Innsbruck, Austria
| | - Anja Krieger-Liszkay
- Institute for Integrative Biology of the Cell (I2BC), Commissariat à l’Energie Atomique et aux Energies Alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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Jokel M, Johnson X, Peltier G, Aro EM, Allahverdiyeva Y. Hunting the main player enabling Chlamydomonas reinhardtii growth under fluctuating light. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:822-835. [PMID: 29575329 DOI: 10.1111/tpj.13897] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Revised: 02/28/2018] [Accepted: 03/02/2018] [Indexed: 05/19/2023]
Abstract
Photosynthetic organisms have evolved numerous photoprotective mechanisms and alternative electron sinks/pathways to fine-tune the photosynthetic apparatus under dynamic environmental conditions, such as varying carbon supply or fluctuations in light intensity. In cyanobacteria flavodiiron proteins (FDPs) protect the photosynthetic apparatus from photodamage under fluctuating light (FL). In Arabidopsis thaliana, which does not possess FDPs, the PGR5-related pathway enables FL photoprotection. The direct comparison of the pgr5, pgrl1 and flv knockout mutants of Chlamydomonas reinhardtii grown under ambient air demonstrates that all three proteins contribute to the survival of cells under FL, but to varying extents. The FDPs are crucial in providing a rapid electron sink, with flv mutant lines unable to survive even mild FL conditions. In contrast, the PGRL1 and PGR5-related pathways operate over relatively slower and longer time-scales. Whilst deletion of PGR5 inhibits growth under mild FL, the pgrl1 mutant line is only impacted under severe FL conditions. This suggests distinct roles, yet a close relationship, between the function of PGR5, PGRL1 and FDP proteins in photoprotection.
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Affiliation(s)
- Martina Jokel
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, FI-20014, Finland
| | - Xenie Johnson
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Gilles Peltier
- Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache, Saint-Paul-lez-Durance, F-13108, France
| | - Eva-Mari Aro
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, FI-20014, Finland
| | - Yagut Allahverdiyeva
- Molecular Plant Biology, Department of Biochemistry, University of Turku, Turku, FI-20014, Finland
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LHCSR Expression under HSP70/RBCS2 Promoter as a Strategy to Increase Productivity in Microalgae. Int J Mol Sci 2018; 19:ijms19010155. [PMID: 29303960 PMCID: PMC5796104 DOI: 10.3390/ijms19010155] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 12/24/2017] [Accepted: 12/31/2017] [Indexed: 11/17/2022] Open
Abstract
Microalgae are unicellular photosynthetic organisms considered as potential alternative sources for biomass, biofuels or high value products. However, limited biomass productivity is commonly experienced in their cultivating system despite their high potential. One of the reasons for this limitation is the high thermal dissipation of the light absorbed by the outer layers of the cultures exposed to high light caused by the activation of a photoprotective mechanism called non-photochemical quenching (NPQ). In the model organism for green algae Chlamydomonas reinhardtii, NPQ is triggered by pigment binding proteins called light-harvesting-complexes-stress-related (LHCSRs), which are over-accumulated in high light. It was recently reported that biomass productivity can be increased both in microalgae and higher plants by properly tuning NPQ induction. In this work increased light use efficiency is reported by introducing in C. reinhardtii a LHCSR3 gene under the control of Heat Shock Protein 70/RUBISCO small chain 2 promoter in a npq4 lhcsr1 background, a mutant strain knockout for all LHCSR genes. This complementation strategy leads to a low expression of LHCSR3, causing a strong reduction of NPQ induction but is still capable of protecting from photodamage at high irradiance, resulting in an improved photosynthetic efficiency and higher biomass accumulation.
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Alric J, Johnson X. Alternative electron transport pathways in photosynthesis: a confluence of regulation. CURRENT OPINION IN PLANT BIOLOGY 2017; 37:78-86. [PMID: 28426976 DOI: 10.1016/j.pbi.2017.03.014] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/23/2017] [Accepted: 03/28/2017] [Indexed: 05/19/2023]
Abstract
Photosynthetic reactions proceed along a linear electron transfer chain linking water oxidation at photosystem II (PSII) to CO2 reduction in the Calvin-Benson-Bassham cycle. Alternative pathways poise the electron carriers along the chain in response to changing light, temperature and CO2 inputs, under prolonged hydration stress and during development. We describe recent literature that reports the physiological functions of new molecular players. Such highlights include the flavodiiron proteins and their important role in the green lineage. The parsing of the proton-motive force between ΔpH and Δψ, regulated in many different ways (cyclic electron flow, ATPsynthase conductivity, ion/H+ transporters), is comprehensively reported. This review focuses on an integrated description of alternative electron transfer pathways and how they contribute to photosynthetic productivity in the context of plant fitness to the environment.
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Affiliation(s)
- Jean Alric
- CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, UMR 7265, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance F-13108, France
| | - Xenie Johnson
- CEA, CNRS, Aix-Marseille Université, Institut de Biosciences et Biotechnologies Aix-Marseille, UMR 7265, Laboratoire de Bioénergétique et Biotechnologie des Bactéries et Microalgues, CEA Cadarache, Saint-Paul-lez-Durance F-13108, France.
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