1
|
Sun R, Okabe M, Miyazaki S, Ishida T, Mashiguchi K, Inoue K, Yoshitake Y, Yamaoka S, Nishihama R, Kawaide H, Nakajima M, Yamaguchi S, Kohchi T. Biosynthesis of gibberellin-related compounds modulates far-red light responses in the liverwort Marchantia polymorpha. THE PLANT CELL 2023; 35:4111-4132. [PMID: 37597168 PMCID: PMC10615216 DOI: 10.1093/plcell/koad216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Revised: 07/17/2023] [Accepted: 07/18/2023] [Indexed: 08/21/2023]
Abstract
Gibberellins (GAs) are key phytohormones that regulate growth, development, and environmental responses in angiosperms. From an evolutionary perspective, all major steps of GA biosynthesis are conserved among vascular plants, while GA biosynthesis intermediates such as ent-kaurenoic acid (KA) are also produced by bryophytes. Here, we show that in the liverwort Marchantia polymorpha, KA and GA12 are synthesized by evolutionarily conserved enzymes, which are required for developmental responses to far-red light (FR). Under FR-enriched conditions, mutants of various biosynthesis enzymes consistently exhibited altered thallus growth allometry, delayed initiation of gametogenesis, and abnormal morphology of gamete-bearing structures (gametangiophores). By chemical treatments and liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses, we confirmed that these phenotypes were caused by the deficiency of some GA-related compounds derived from KA, but not bioactive GAs from vascular plants. Transcriptome analysis showed that FR enrichment induced the up-regulation of genes related to stress responses and secondary metabolism in M. polymorpha, which was largely dependent on the biosynthesis of GA-related compounds. Due to the lack of canonical GA receptors in bryophytes, we hypothesize that GA-related compounds are commonly synthesized in land plants but were co-opted independently to regulate responses to light quality change in different plant lineages during the past 450 million years of evolution.
Collapse
Affiliation(s)
- Rui Sun
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,Japan
| | - Maiko Okabe
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,Japan
| | - Sho Miyazaki
- Institute of Global Innovation Research, Tokyo University of Agriculture and Technology, Fuchu, 183-8509,Japan
| | - Toshiaki Ishida
- Institute for Chemical Research, Kyoto University, Uji 611-0011,Japan
| | | | - Keisuke Inoue
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,Japan
| | | | - Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,Japan
| | - Ryuichi Nishihama
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,Japan
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, Noda 278-8510,Japan
| | - Hiroshi Kawaide
- Institute of Agriculture, Tokyo University of Agriculture and Technology, Tokyo 183-8509,Japan
| | - Masatoshi Nakajima
- Department of Applied Biological Chemistry, The University of Tokyo, Tokyo 113-8657,Japan
| | | | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,Japan
| |
Collapse
|
2
|
Kusuma P, Bugbee B. Improving the Predictive Value of Phytochrome Photoequilibrium: Consideration of Spectral Distortion Within a Leaf. FRONTIERS IN PLANT SCIENCE 2021; 12:596943. [PMID: 34108976 PMCID: PMC8181145 DOI: 10.3389/fpls.2021.596943] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 04/28/2021] [Indexed: 06/01/2023]
Abstract
The ratio of active phytochrome (Pfr) to total phytochrome (Pr + Pfr), called phytochrome photo-equilibrium (PPE; also called phytochrome photostationary state, PSS) has been used to explain shade avoidance responses in both natural and controlled environments. PPE is commonly estimated using measurements of the spectral photon distribution (SPD) above the canopy and photoconversion coefficients. This approach has effectively predicted morphological responses when only red and far-red (FR) photon fluxes have varied, but controlled environment research often utilizes unique ratios of wavelengths so a more rigorous evaluation of the predictive ability of PPE on morphology is warranted. Estimations of PPE have rarely incorporated the optical effects of spectral distortion within a leaf caused by pigment absorbance and photon scattering. We studied stem elongation rate in the model plant cucumber under diverse spectral backgrounds over a range of one to 45% FR (total photon flux density, 400-750 nm, of 400 μmol m-2 s-1) and found that PPE was not predictive when blue and green varied. Preferential absorption of red and blue photons by chlorophyll results in an SPD that is relatively enriched in green and FR at the phytochrome molecule within a cell. This can be described by spectral distortion functions for specific layers of a leaf. Multiplying the photoconversion coefficients by these distortion functions yields photoconversion weighting factors that predict phytochrome conversion at the site of photon perception within leaf tissue. Incorporating spectral distortion improved the predictive value of PPE when phytochrome was assumed to be homogeneously distributed within the whole leaf. In a supporting study, the herbicide norflurazon was used to remove chlorophyll in seedlings. Using distortion functions unique to either green or white cotyledons, we came to the same conclusions as with whole plants in the longer-term study. Leaves of most species have similar spectral absorbance so this approach for predicting PPE should be broadly applicable. We provide a table of the photoconversion weighting factors. Our analysis indicates that the simple, intuitive ratio of FR (700-750 nm) to total photon flux (far-red fraction) is also a reliable predictor of morphological responses like stem length.
Collapse
|
3
|
Montgomery BL. Spatiotemporal Phytochrome Signaling during Photomorphogenesis: From Physiology to Molecular Mechanisms and Back. FRONTIERS IN PLANT SCIENCE 2016; 7:480. [PMID: 27148307 PMCID: PMC4826876 DOI: 10.3389/fpls.2016.00480] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 03/24/2016] [Indexed: 05/21/2023]
Abstract
Light exposure results in distinct responses in specific seedling tissues during photomorphogenesis. Light promotes growth of cotyledons and leaves, as well as development and elongation of roots, whereas light inhibits elongation of hypocotyls. For distinct plant responses such as shade avoidance, far-red light or shifts in spectral light quality similarly have disparate impacts on distinct plant tissues, resulting in elongation of stems or petioles and a reduction in growth of leaf blades for many species. The physiological bases of such tissue- and organ-specific light responses were initially studied using localized irradiation of specific tissues and organs, or irradiation of dissected plant parts. These historical approaches were used to identify spatial-specific pools of photoreceptors responsible for regulating local, i.e., tissue- or organ-specific, or distal, i.e., interorgan, plant responses. The red/far-red responsive phytochromes have been the most widely studied among photoreceptors in this regard. Whereas, the spatial localization of photoreceptors regulating many tissue- or organ-specific light responses were identified, the underlying signaling networks responsible for mediating the observed responses have not been well defined. Recent approaches used to investigate the molecular bases of spatiotemporal light responses include selective irradiation of plants harboring mutations in specific photoreceptors, tissue-specific expression of photoreceptors, primarily in photoreceptor mutant backgrounds, or tissue-specific biochemical ablation of photoreceptor accumulation. Progressive integration of such approaches for regulating the availability of localized pools of phytochromes with the use of transcriptomic or proteomic analyses for assessing the genes or proteins which these spatially discrete pools of phytochrome regulate is yielding emergent insight into the molecular bases of spatiotemporal phytochrome signaling pathways responsible for regulating spatiotemporal light responses of which we have been aware of at the physiological level for decades. Here, I discuss historical and emerging approaches to elucidating spatiotemporal signaling mediated by phytochromes during photomorphogenesis.
Collapse
Affiliation(s)
- Beronda L. Montgomery
- Department of Energy — Plant Research Laboratory, Michigan State UniversityEast Lansing, MI, USA
- Department of Biochemistry and Molecular Biology, Michigan State UniversityEast Lansing, MI, USA
- *Correspondence: Beronda L. Montgomery,
| |
Collapse
|
4
|
Procko C, Crenshaw CM, Ljung K, Noel JP, Chory J. Cotyledon-Generated Auxin Is Required for Shade-Induced Hypocotyl Growth in Brassica rapa. PLANT PHYSIOLOGY 2014; 165:1285-1301. [PMID: 24891610 PMCID: PMC4081337 DOI: 10.1104/pp.114.241844] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 06/01/2014] [Indexed: 05/20/2023]
Abstract
Plant architecture is optimized for the local light environment. In response to foliar shade or neighbor proximity (low red to far-red light), some plant species exhibit shade-avoiding phenotypes, including increased stem and hypocotyl growth, which increases the likelihood of outgrowing competitor plants. If shade persists, early flowering and the reallocation of growth resources to stem elongation ultimately affect the yield of harvestable tissues in crop species. Previous studies have shown that hypocotyl growth in low red to far-red shade is largely dependent on the photoreceptor phytochrome B and the phytohormone auxin. However, where shade is perceived in the plant and how auxin regulates growth spatially are less well understood. Using the oilseed and vegetable crop species Brassica rapa, we show that the perception of low red to far-red shade by the cotyledons triggers hypocotyl cell elongation and auxin target gene expression. Furthermore, we find that following shade perception, elevated auxin levels occur in a basipetal gradient away from the cotyledons and that this is coincident with a gradient of auxin target gene induction. These results show that cotyledon-generated auxin regulates hypocotyl elongation. In addition, we find in mature B. rapa plants that simulated shade does not affect seed oil composition but may affect seed yield. This suggests that in field settings where mutual shading between plants may occur, a balance between plant density and seed yield per plant needs to be achieved for maximum oil yield, while oil composition might remain constant.
Collapse
Affiliation(s)
- Carl Procko
- Plant Biology Laboratory (C.P., J.C.), Jack H. Skirball Center for Chemical Biology and Proteomics (C.M.C., J.P.N.), and Howard Hughes Medical Institute (C.M.C., J.P.N., J.C.), Salk Institute for Biological Studies, La Jolla, California 92037; andUmeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden (K.L.)
| | - Charisse Michelle Crenshaw
- Plant Biology Laboratory (C.P., J.C.), Jack H. Skirball Center for Chemical Biology and Proteomics (C.M.C., J.P.N.), and Howard Hughes Medical Institute (C.M.C., J.P.N., J.C.), Salk Institute for Biological Studies, La Jolla, California 92037; andUmeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden (K.L.)
| | - Karin Ljung
- Plant Biology Laboratory (C.P., J.C.), Jack H. Skirball Center for Chemical Biology and Proteomics (C.M.C., J.P.N.), and Howard Hughes Medical Institute (C.M.C., J.P.N., J.C.), Salk Institute for Biological Studies, La Jolla, California 92037; andUmeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden (K.L.)
| | - Joseph Patrick Noel
- Plant Biology Laboratory (C.P., J.C.), Jack H. Skirball Center for Chemical Biology and Proteomics (C.M.C., J.P.N.), and Howard Hughes Medical Institute (C.M.C., J.P.N., J.C.), Salk Institute for Biological Studies, La Jolla, California 92037; andUmeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden (K.L.)
| | - Joanne Chory
- Plant Biology Laboratory (C.P., J.C.), Jack H. Skirball Center for Chemical Biology and Proteomics (C.M.C., J.P.N.), and Howard Hughes Medical Institute (C.M.C., J.P.N., J.C.), Salk Institute for Biological Studies, La Jolla, California 92037; andUmeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umea, Sweden (K.L.)
| |
Collapse
|
5
|
Cole B, Kay SA, Chory J. Automated analysis of hypocotyl growth dynamics during shade avoidance in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 65:991-1000. [PMID: 21288269 PMCID: PMC3076959 DOI: 10.1111/j.1365-313x.2010.04476.x] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Plants that are adapted to environments where light is abundant are especially sensitive to competition for light from neighboring vegetation. As a result, these plants initiate a series of changes known as the shade avoidance syndrome, during which plants elongate their stems and petioles at the expense of leaf development. Although the developmental outcomes of exposure to prolonged shade are known, the signaling dynamics during the initial exposure of seedlings to shade is less well studied. Here, we report the development of a new software-based tool, called HyDE (Hypocotyl Determining Engine) to measure hypocotyl lengths of time-resolved image stacks of Arabidopsis wild-type and mutant seedlings. We show that Arabidopsis grows rapidly in response to the shade stimulus, with measurable growth after just 45 min shade exposure. Similar to other mustard species, this growth response occurs in multiple distinct phases, including two phases of rapid growth and one phase of slower growth. Using mutants affected in shade avoidance phenotypes, we demonstrate that most of this early growth requires new auxin biosynthesis via the indole-3-pyruvate pathway. When activity of this pathway is reduced, the first phase of elongation growth is absent, and this is correlated with reduced activity of auxin-regulated genes. Finally, we show that varying shade intensity and duration can affect the shape and magnitude of the growth response, indicating a broad range of the elongation response to shade.
Collapse
Affiliation(s)
- Benjamin Cole
- Plant Biology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037 U.S.A
- Division of Biological Sciences, University of California - San Diego, 9500 Gillman Dr. La Jolla, CA 92037 U.S.A
| | - Steve A. Kay
- Division of Biological Sciences, University of California - San Diego, 9500 Gillman Dr. La Jolla, CA 92037 U.S.A
| | - Joanne Chory
- Plant Biology Laboratory, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037 U.S.A
- Howard Hughes Medical Institute, The Salk Institute for Biological Studies, 10010 N. Torrey Pines Rd., La Jolla, CA 92037 U.S.A
- For correspondence: Tel (858)-453-4100 x1690, Fax (858)-453-558-6379,
| |
Collapse
|
6
|
Pierik R, De Wit M, Voesenek LACJ. Growth-mediated stress escape: convergence of signal transduction pathways activated upon exposure to two different environmental stresses. THE NEW PHYTOLOGIST 2011; 189:122-34. [PMID: 20854397 DOI: 10.1111/j.1469-8137.2010.03458.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
• Plants can escape from specific environmental stresses through active growth strategies. Here, we compared two such stress-escape syndromes to investigate whether plants use conserved signal transduction pathways to escape from different stresses. • Full submergence is a threat to terrestrial plants as it cuts off their access to oxygen and CO(2). Proximate neighbors, in contrast, take away resources such as light. Both submergence and shade can be escaped through rapid shoot elongation. We analysed the precise kinetics and physiological control of petiole elongation responses to shade and submergence in the flood-tolerant species Rumex palustris. • We found that petiole elongation induced by submergence and that induced by shade occurred with similar kinetics, both involving cell expansion. These responses were induced by two different signals, elevated ethylene and a reduced red : far-red light ratio (R : FR), respectively. A downstream target for ethylene was abscisic acid, but low R : FR appeared to act independently of this hormone. Gibberellin, however, appeared to be essential to both ethylene- and low R : FR-induced petiole elongation. • We propose that gibberellin and expansins, a family of cell wall-loosening proteins, represent elements of a conserved growth machinery that is activated by stress-specific signaling events to regulate escape from stress.
Collapse
Affiliation(s)
- Ronald Pierik
- Plant Ecophysiology, Institute of Environmental Biology, Utrecht University, Utrecht, the Netherlands.
| | | | | |
Collapse
|
7
|
Montgomery BL. Right place, right time: Spatiotemporal light regulation of plant growth and development. PLANT SIGNALING & BEHAVIOR 2008; 3:1053-60. [PMID: 19513238 PMCID: PMC2634459 DOI: 10.4161/psb.3.12.6857] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2008] [Accepted: 08/27/2008] [Indexed: 05/21/2023]
Abstract
Recent advances in our understanding of the roles of photoreceptors in light-dependent regulation of plant growth and development have been rapid and significant. Developments have been reported for numerous plant photoreceptor signaling pathways, yet researchers have made the most progress in increasing our comprehension of the roles of phytochrome family members, as well as the intracellular roles of phytochromes and phytochrome-interacting proteins in light-dependent signaling. An understudied, but vitally important, area of phytochrome biology centers on the roles phytochromes play in intercellular and interorgan signaling at the molecular level that results in the coordination of growth responses between distinct tissues and organs. This frontier of research into the spatiotemporal roles of phytochromes, and more generally plant photoreceptors, which is only beginning to be investigated and understood at the molecular genetic level, has a rich history of physiological data.
Collapse
Affiliation(s)
- Beronda L Montgomery
- Department of Energy-Plant Research Laboratory and Department of Biochemistry and Molecular Biology; Michigan State University; East Lansing, Michigan USA
| |
Collapse
|
8
|
Bou-Torrent J, Roig-Villanova I, Martínez-García JF. Light signaling: back to space. TRENDS IN PLANT SCIENCE 2008; 13:108-14. [PMID: 18280200 DOI: 10.1016/j.tplants.2007.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2007] [Revised: 11/23/2007] [Accepted: 12/05/2007] [Indexed: 05/04/2023]
Abstract
Recent work has increased our understanding of the molecular and cellular mechanisms of the phytochrome family of photoreceptors in controlling plant photomorphogenesis. However, the importance of long-distance communication in controlling light responses has received relatively little attention and is poorly understood. In this article, by taking a closer look at old and new experiments that extend the analysis of light signaling beyond the limits of the plant cell, we offer to look at the field in a new light. Furthermore, we discuss how intercellular and inter-organ communication might integrate with the transcriptional networks controlling light-regulated responses in plants, a novel view that might help to re-assess the parameters by which we screen for photomorphogenic mutants in the future.
Collapse
Affiliation(s)
- Jordi Bou-Torrent
- Departament de Genètica Molecular IBMB, Laboratori de Genètica Molecular Vegetal, Consorci CSIC-IRTA, c. Jordi Girona, 18-26, 08034 Barcelona, Spain
| | | | | |
Collapse
|
9
|
Hisamatsu T, King RW, Helliwell CA, Koshioka M. The involvement of gibberellin 20-oxidase genes in phytochrome-regulated petiole elongation of Arabidopsis. PLANT PHYSIOLOGY 2005; 138:1106-16. [PMID: 15923331 PMCID: PMC1150424 DOI: 10.1104/pp.104.059055] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 02/10/2005] [Accepted: 02/15/2005] [Indexed: 05/02/2023]
Abstract
Long day (LD) exposure of rosette plants causes rapid stem/petiole elongation, a more vertical growth habit, and flowering; all changes are suggestive of a role for the gibberellin (GA) plant growth regulators. For Arabidopsis (Arabidopsis thaliana) L. (Heynh), we show that enhancement of petiole elongation by a far-red (FR)-rich LD is mimicked by a brief (10 min) end-of-day (EOD) FR exposure in short day (SD). The EOD response shows red (R)/FR photoreversibility and is not affected in a phytochrome (PHY) A mutant so it is mediated by PHYB and related PHYs. FR photoconversion of PHYB to an inactive form activates a signaling pathway, leading to increased GA biosynthesis. Of 10 GA biosynthetic genes, expression of the 20-oxidase, AtGA20ox2, responded most to FR (up to a 40-fold increase within 3 h). AtGA20ox1 also responded but to a lesser extent. Stimulation of petiole elongation by EOD FR is reduced in a transgenic AtGA20ox2 hairpin gene silencing line. By contrast, it was only in SD that a T-DNA insertional mutant of AtGA20ox1 (ga5-3) showed reduced response. Circadian entrainment to a daytime pattern provides an explanation for the SD expression of AtGA20ox1. Conversely, the strong EOD/LD FR responses of AtGA20ox2 may reflect its independence of circadian regulation. While FR acting via PHYB increases expression of AtGA20ox2, other GA biosynthetic genes are known to respond to R rather than FR light and/or to other PHYs. Thus, there must be different signal transduction pathways, one at least showing a positive response to active PHYB and another showing a negative response.
Collapse
Affiliation(s)
- Tamotsu Hisamatsu
- National Institute of Floricultural Science, Tsukuba 305-8519, Japan
| | | | | | | |
Collapse
|
10
|
Pierik R, Cuppens MLC, Voesenek LACJ, Visser EJW. Interactions between ethylene and gibberellins in phytochrome-mediated shade avoidance responses in tobacco. PLANT PHYSIOLOGY 2004; 136:2928-36. [PMID: 15448197 PMCID: PMC523355 DOI: 10.1104/pp.104.045120] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2004] [Revised: 06/09/2004] [Accepted: 07/06/2004] [Indexed: 05/18/2023]
Abstract
Plants respond to proximate neighbors with a suite of responses that comprise the shade avoidance syndrome. These phytochrome-mediated responses include hyponasty (i.e. a more vertical orientation of leaves) and enhanced stem and petiole elongation. We showed recently that ethylene-insensitive tobacco (Nicotiana tabacum) plants (Tetr) have reduced responses to neighbors, showing an important role for this gaseous plant hormone in shade avoidance. Here, we investigate interactions between phytochrome signaling and ethylene action in shade avoidance responses. Furthermore, we investigate if ethylene acts in these responses through an interaction with the GA class of hormones. Low red to far-red light ratios (R:FR) enhanced ethylene production in wild-type tobacco, resulting in shade avoidance responses, whereas ethylene-insensitive plants showed reduced shade avoidance responses. Plants with inhibited GA production showed hardly any shade avoidance responses at all to either a low R:FR or increased ethylene concentrations. Furthermore, low R:FR enhanced the responsiveness of hyponasty and stem elongation in both wild-type and Tetr plants to applied GA(3), with the stem elongation process being more responsive to GA(3) in the wild type than in Tetr. We conclude that phytochrome-mediated shade avoidance responses involve ethylene action, at least partly by modulating GA action.
Collapse
Affiliation(s)
- Ronald Pierik
- Department of Experimental Plant Ecology, Radboud University Nijmegen, Toernooiveld, 6525 ED Nijmegen, The Netherlands.
| | | | | | | |
Collapse
|
11
|
Olsen JE, Junttila O. Far red end-of-day treatment restores wild type-like plant length in hybrid aspen overexpressing phytochrome A. PHYSIOLOGIA PLANTARUM 2002; 115:448-457. [PMID: 12081538 DOI: 10.1034/j.1399-3054.2002.1150315.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Shoot elongation in woody plants is modulated by a multitude of light signals, including irradiance, photoperiod and spectral composition, for which the phytochrome system is the probable photoreceptor. In hybrid aspen (Populus tremula x tremuloides) overexpression of the oat phytochrome A (PHYA) prevents growth cessation in response to short photoperiod, and plants exhibit dwarf growth that is related to reduced cell numbers and reduced gibberellin contents. End-of-day far-red treatment significantly enhances internode elongation in PHYA overexpressors as well as in the wild type, and this was found here to be caused by stimulation of cell division and cell extension. In PHYA overexpressors the effects were substantially larger than in the wild type, and resulted in complete restoration of wild type-like plant length as well as cell numbers, and gibberellin content was greatly increased. No clear effect of far-red end-of-day treatment on gibberellin levels could be detected in the wild type. It thus appears that the far-red end-of-day treatment might modify the responsiveness of the tissue to GA rather than the GA levels. The observed effects were completely reversed by a subsequent irradiation with red light. The present data show that dwarfism due to PHYA overexpression can be completely overcome by far red end-of-day treatment, and the observations indicate that effects of far red end-of-day treatments appear to be mediated by phytochrome(s) other than phytochrome A.
Collapse
Affiliation(s)
- Jorunn E Olsen
- Department of Biology, University of Tromsø, N 9037 Tromsø, Norway Present address: Department of Biology and Nature Conservation, Box 5014, Agricultural University of Norway, N-1432 As, Norway
| | | |
Collapse
|
12
|
SAOS FLEGUEN, HOURMANT A, ESNAULT F, CHAUVIN JE. In vitro bulb development in shallot (Allium cepa L. Aggregatum Group): effects of anti-gibberellins, sucrose and light. ANNALS OF BOTANY 2002; 89:419-425. [PMID: 12096802 PMCID: PMC4233876 DOI: 10.1093/aob/mcf063] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Bulbing was studied in shallot plants cultured in vitro. Bulbing occurred under a 16 h photoperiod with fluorescent + incandescent light and 30-50 g 1(-1) sucrose in the culture medium. Exogenous gibberellin (10 microM GA3) inhibited leaf and root growth and bulbing. When added to the medium at a concentration of 10 microM, three inhibitors of gibberellin biosynthesis (ancymidol, flurprimidol and paclobutrazol) promoted bulb formation and the percentage of bulbing. When ancymidol was used in combination with GA3, it did not reverse the effect of GA3 applied alone. Under treatments with 30-70 g l(-1) sucrose, bulbing ratios greater than those found in control plants were achieved by addition of ancymidol, and bulb fresh weight was increased in the same way. Ancymidol caused a 66% decrease in sucrose content in leaf bases but greatly increased the glucose, fructose and fructan contents. The increase in fructan content by ancymidol could result from the three-fold rise in total [14C]sucrose uptake per plant from the culture medium associated with a marked increase in leaf base labelling at the expense of root labelling. The possible role of ancymidol is discussed and evidence supports a major regulatory role for gibberellins in bulbing.
Collapse
Affiliation(s)
- F. LE GUEN‐LE SAOS
- Université de Bretagne Occidentale, Laboratoire de Biotechnologie et Physiologie Végétales, 6 Avenue Victor Le Gorgeu, BP 809, 29285 Brest cedex, France
| | - A. HOURMANT
- Université de Bretagne Occidentale, Laboratoire de Biotechnologie et Physiologie Végétales, 6 Avenue Victor Le Gorgeu, BP 809, 29285 Brest cedex, France
| | - F. ESNAULT
- INRA Station d’amélioration de la pomme de terre et des plantes à bulbes, Domaine de Kéraïber, 29260 Ploudaniel, France
| | - J. E. CHAUVIN
- INRA Station d’amélioration de la pomme de terre et des plantes à bulbes, Domaine de Kéraïber, 29260 Ploudaniel, France
| |
Collapse
|
13
|
Abstract
The recent impressive progress in research on gibberellin (GA) biosynthesis has resulted primarily from cloning of genes encoding biosynthetic enzymes and studies with GA-deficient and GA-insensitive mutants. Highlights include the cloning of ent-copalyl diphosphate synthase and ent-kaurene synthase (formally ent-kaurene synthases A and B) and the demonstration that the former is targeted to the plastid; the finding that the Dwarf-3 gene of maize encodes a cytochrome P450, although of unknown function; and the cloning of GA 20-oxidase and 3beta-hydroxylase genes. The availability of cDNA and genomic clones for these enzymes is enabling the mechanisms by which GA concentrations are regulated by environmental and endogenous factors to be studied at the molecular level. For example, it has been shown that transcript levels for GA 20-oxidase and 3beta-hydroxylase are subject to feedback regulation by GA action and, in the case of the GA 20-oxidase, are regulated by light. Also discussed is other new information, particularly from mutants, that has added to our understanding of the biosynthetic pathway, the enzymes, and their regulation and tissue localization.
Collapse
Affiliation(s)
- Peter Hedden
- IACR-Long Ashton Research Station, Department of Agricultural Science, University of Bristol, Bristol, BS18 9AF, United Kingdom, Frontier Research Program, The Institute of Physical and Chemical Research (RIKEN), Hirosawa 2-1, Wako-shi, Saitama 351-01, Japan
| | | |
Collapse
|
14
|
|
15
|
Hill C, Gärtner W, Towner P, Braslavsky SE, Schaffner K. Expression of phytochrome apoprotein from Avena sativa in Escherichia coli and formation of photoactive chromoproteins by assembly with phycocyanobilin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 223:69-77. [PMID: 8033910 DOI: 10.1111/j.1432-1033.1994.tb18967.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Phytochrome DNAs from oat (Avena sativa L.) encoding the full-length 124-kDa polypeptide, a 118-kDa fragment lacking the first 65 amino acids, and two N-terminal fragments of 65 kDa and 45 kDa were subcloned and expressed in Escherichia coli. Reducing the temperature to 25 degrees C during cell growth and the coexpression of chaperones improved the folding into a functional conformation for most of the polypeptides, and in one case the yield of polypeptides was also enhanced. A maximum yield of reconstitutable apoprotein was obtained by expressing the 65-kDa fragment consisting of 595 amino acids. The apoproteins could be assembled in the dark with phycocyanobilin into photoreversible chromoproteins. The yield of photoreversible pigment could be further increased by far-red/red irradiation cycles, indicating that the presence of the chromophore promotes the correct folding of the binding site. The chromoproteins with an intact N-terminal domain exhibit Pr and Pfr absorption bands, which are blue-shifted relative to the corresponding bands of native phytochrome due to the particular phycocyanobilin structure. The 118-kDa fragment, only lacking the 6-kDa N-terminus, exhibits a strong Pr band, but only a weak Pfr absorbance. This indicates an essential role of the front 6-kDa region of the protein in the formation of the far-red absorbing chromophore-protein complex. Otherwise, the C-terminal region seems to be less important for photoreversibility as indicated by the function of the shorter fragments.
Collapse
Affiliation(s)
- C Hill
- Max-Planck-Institut für Strahlenchemic, Mülheim an der Ruhr, Germany
| | | | | | | | | |
Collapse
|
16
|
Hutchings M, de Kroon H. Foraging in Plants: the Role of Morphological Plasticity in Resource Acquisition. ADV ECOL RES 1994. [DOI: 10.1016/s0065-2504(08)60215-9] [Citation(s) in RCA: 515] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
|
17
|
Dobert RC, Rood SB, Zanewich K, Blevins DG. Gibberellins and the Legume-Rhizobium Symbiosis : III. Quantification of Gibberellins from Stems and Nodules of Lima Bean and Cowpea. PLANT PHYSIOLOGY 1992; 100:1994-2001. [PMID: 16653229 PMCID: PMC1075896 DOI: 10.1104/pp.100.4.1994] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Lima bean (Phaseolus lunatus L.) plants inoculated with Bradyrhizobium sp. strain 127E14 displayed a period of marked internode elongation that was not observed in plants inoculated with other compatible bradyrhizobia, including strain 127E15. When strain 127E14 nodulated an alternate host, cowpea (Vigna unguiculata L. Walp), a similar, although less dramatic growth response induced by the bacteria was observed. It has been speculated that the elongative growth promotion brought about by inoculation with strain 127E14 is mediated by gibberellins (GAs). Using deuterated internal standards and gas chromatography-mass spectroscopy analysis, we have quantified the levels of GA(1), GA(20), GA(19), and GA(44) in nodules and stems of two varieties of lima bean (bush and pole) and one variety of cowpea that were inoculated with either strain 127E14 or 127E15. In nodules formed by strain 127E14 on lima bean, endogenous levels of GA(20) and GA(19) were 10 to 40 times higher (35-88 ng/g dry weight) than amounts found in nodules formed by strain 127E15 (2.2-3.9 ng/g dry weight). Relative amounts of GA(44) were also higher (4- to 11-fold) in 127E14 nodules, but this increase was less pronounced. The rhizobial-induced increase of these GAs in the nodule occurred in both pole and bush varieties and seemed to be independent of host morphology. Regardless of rhizobial inoculum, levels of the "bioactive" GA(1) in the nodule (0.3-1.1 ng/g dry weight) were similar. In cowpea nodules, a similar, although smaller, difference in GA content due to rhizobial strain was observed. The concentration of GA(1) in lima bean stems was generally higher than that observed in the nodule, whereas concentrations of the other GAs measured were lower. In contrast with the nodule, GA concentrations in lima bean stems were not greater in plants inoculated with strain 127E14, and in some cases the slower growing plants inoculated with strain 127E15 actually had higher levels of GA(20), GA(19), and GA(44). Thus, there were major differences in concentrations of the precursors to GA(1) in nodules formed by the two bacterial strains, which were positively correlated with the observed elongation growth. These results support the hypothesis that the rhizobial strain modifies the endogenous GA status of the symbiotic system. This alteration in GA balance within the plant, presumably, underlies the observed growth response.
Collapse
Affiliation(s)
- R C Dobert
- Interdisciplinary Plant Group, Agronomy Department, University of Missouri, Columbia, Missouri 65211
| | | | | | | |
Collapse
|
18
|
Martínez-García JF, García-Martínez JL. Effect of the growth retardant LAB 198 999, an acylcyclohexanedione compound, on epicotyl elongation and metabolism of gibberellins A1 and A 20 in cowpea. PLANTA 1992; 188:245-251. [PMID: 24178261 DOI: 10.1007/bf00216820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 04/15/1992] [Indexed: 06/02/2023]
Abstract
The effect of LAB 198 999 [3,5-dioxo-4-butyryl-cyclohexane carboxylic acid ethyl ester; a new plant growth retardant which competitively inhibits 2-oxoglutarate-dependent gibberellin (GA) dioxygenases] on elongation and in-vivo [(3)H]GA1 and [(3)H]GA20 metabolism in cowpea (Vigna sinensis L. cv Blackeye pea No. 5) epicotyls has been investigated. Gibberellins and LAB 198 999 were injected into the epicotyl at 25-30 mm from the apex. In intact seedlings, epicotyl elongation was inhibited by LAB 198 999 (25 μg · epicotyl(-1)), and the inhibition was counteracted by GA1 but not by GA20. In contrast to intact seedlings, the inhibitor enhanced epicotyl elongation in de-bladed seedlings and expiants, in the latter case proportionally to the amount of inhibitor applied (up to 50 μg · epicotyl(-1)), but not in explants made from paclobutrazol-treated seedlings. The inhibitor also enhanced dramatically the elongation induced in paclobutrazol-treated expiants by GA1, but not by GA20. The promotive effect of LAB 198 999 was associated with increased contents of GA1 and GA8 in the growing region of the epicotyl, indicating a dependence on endogenous GAs. The effect of LAB 198999 decreased progressively with the age of the seedlings, probably as a consequence of a decreased level of GAs in the epicotyl. Gibberellin substrates and metabolites in the growing region of the epicotyl (upper 20 mm) were fractionated and identified tentatively by high-performance liquid chromatography and radiocounting using a homogeneous on-line radioactivity detector. The metabolism of [(3)H]GA1(t) (tentative) to [(3)H]GA8(t), and that of [(3)H]GA20(t) to [(3)H]GA1(t) and [(3)H]GA29(t) in the epicotyl were blocked by LAB 198 999, that of the former more efficiently than the latter. The results presented support the hypothesis that GA1 is the active GA controlling elongation of cowpea epicotyls. They also show that both the promotion of epicotyl elongation in explants and the enhancement of the effect of exogenous GA1 by LAB 198 999 are the result of the inhibitor blocking the in-vivo 2β-hydroxylation of GA1.
Collapse
Affiliation(s)
- J F Martínez-García
- Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Jaime Roig 11, E-46010, Valencia, Spain
| | | |
Collapse
|
19
|
|
20
|
|
21
|
López-Juez E, Buurmeijer WF, Heeringa GH, Kendrick RE, Wesselius JC. RESPONSE OF LIGHT-GROWN WILD-TYPE and LONG HYPOCOTYL MUTANT CUCUMBER PLANTS TO END-OF-DAY FAR-RED LIGHT. Photochem Photobiol 1990. [DOI: 10.1111/j.1751-1097.1990.tb01767.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
|
22
|
López-Juez E, Nagatani A, Buurmeijer W, Peters J, Furuya M, Kendrick R, Wesselius J. Response of light-grown wild-type and aurea-mutant tomato plants to end-of-day far-red light. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 1990. [DOI: 10.1016/1011-1344(90)85018-r] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
23
|
Ballaré CL, Scopel AL, Sánchez RA. Photomodulation of axis extension in sparse canopies : role of the stem in the perception of light-quality signals of stand density. PLANT PHYSIOLOGY 1989; 89:1324-30. [PMID: 16666704 PMCID: PMC1056016 DOI: 10.1104/pp.89.4.1324] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
A fiber optic probe inserted into plant tissues was used to investigate the effects of canopy density on the light environment in different organs. The red:far-red ratio inside the stem of Datura ferox L. seedlings and the estimated phytochrome photoequilibrium were strongly reduced by the presence of neighbors forming canopies too sparse to cause any mutual shading at the level of the leaves. In such canopies, changes in plant density had little effects on the light regime inside the leaves of the succulent Aeonium haworthii (S.D.) Webb et Berth., particularly when the lamina was kept nearly normal to the direct rays of the sun. In field experiments using D. ferox and Sinapis alba L. seedlings, the elongation of the internodes responded to various types of localized light-quality treatments that simulated different plant densities in sparse canopies. The responses were quantitatively similar to those elicited by changes in plant density. The evidence supports the hypothesis that, in stands formed by plants of similar size, the red:far-red ratio of the light that impinges laterally on the stems is among the earliest environmental cues that allow plants to detect local canopy density and adjust axis extension accordingly.
Collapse
Affiliation(s)
- C L Ballaré
- Departamento de Ecología, Facultad de Agronomía, Universidad de Buenos Aires, Avda. San Martín 4453, (1417) Buenos Aires, Argentina
| | | | | |
Collapse
|
24
|
Casal JJ, Smith H. The loci of perception for phytochrome control of internode growth in light-grown mustard: Promotion by low phytochrome photoequilibria in the internode is enhanced by blue light perceived by the leaves. PLANTA 1988; 176:277-82. [PMID: 24220784 DOI: 10.1007/bf00392456] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/1988] [Accepted: 06/30/1988] [Indexed: 05/04/2023]
Abstract
Under continuous white light (WL), extension growth of the first internode in Sinapis alba L. was promoted by low red (R): far-red (FR) ratios reaching the stem and-or the leaves. Conversely, the growth promotion by end-of-day light treatments was only triggered by FR perceived by the leaves and cotyledons, while FR given to the growning internode alone was tatally ineffective. Continuous WL+FR given to the internode was also in-effective if the rest of the shoot remained in darkness. Both the background stem growth, and the growth promotion caused by either an end-of-day FR pulse or continuous WL+FR given to the internode, increased with increasing fluence rates of WL given to the rest of the shoot. The increase by WL of the growth-stimulatory effect of low phytochrome photoequilibria in the internode appears to be mediated by a specific blue-light-absorbing photoreceptor, as blue-deficient light from sodium-discharge lamps, or from filtered fluorescent tubes, promoted background stem growth similarly to WL but did not amplify the response to the R:FR ratio in the internode. Supplementing the blue-deficient light (94 μmol·m(-2)·s(-1)) with low fluence rates of blue (<9 μmol·m(-2)·s(-1)) restored the promotive effect of low R:FR reaching the internode.
Collapse
Affiliation(s)
- J J Casal
- Department of Botany, University of Leicester, University Road, LE1 7RH, Leicester, UK
| | | |
Collapse
|