151
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Gardiner J. Posttranslational modification of plant microtubules. PLANT SIGNALING & BEHAVIOR 2019; 14:e1654818. [PMID: 31564233 PMCID: PMC6768230 DOI: 10.1080/15592324.2019.1654818] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 08/01/2019] [Accepted: 08/07/2019] [Indexed: 06/10/2023]
Abstract
Microtubules in eukaryotes have a number of posttranslational modifications catalyzed by an array of enzymes. These modifications alter the properties of the microtubules and the ways in which they interact with partner proteins. In recent years many of the enzymes which modify the microtubules have been identified in animals and protozoans. Relatively little work has been done on their function in plants, however. This study uses bioinformatics to identify homologues of these enzymes in plant species from the green alga Chlamydomonas reiinhardtii to the angiosperm Arabidopsis thaliana. Many are conserved and this gives insight into the likely future direction of this dynamic field.
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152
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Gabilly ST, Baker CR, Wakao S, Crisanto T, Guan K, Bi K, Guiet E, Guadagno CR, Niyogi KK. Regulation of photoprotection gene expression in Chlamydomonas by a putative E3 ubiquitin ligase complex and a homolog of CONSTANS. Proc Natl Acad Sci U S A 2019; 116:17556-17562. [PMID: 31405963 PMCID: PMC6717296 DOI: 10.1073/pnas.1821689116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Photosynthetic organisms use nonphotochemical quenching (NPQ) mechanisms to dissipate excess absorbed light energy and protect themselves from photooxidation. In the model green alga Chlamydomonas reinhardtii, the capacity for rapidly reversible NPQ (qE) is induced by high light, blue light, and UV light via increased expression of LHCSR and PSBS genes that are necessary for qE. Here, we used a forward genetics approach to identify SPA1 and CUL4, components of a putative green algal E3 ubiquitin ligase complex, as critical factors in a signaling pathway that controls light-regulated expression of the LHCSR and PSBS genes in C. reinhardtii The spa1 and cul4 mutants accumulate increased levels of LHCSR1 and PSBS proteins in high light, and unlike the wild type, they express LHCSR1 and exhibit qE capacity even when grown in low light. The spa1-1 mutation resulted in constitutively high expression of LHCSR and PSBS RNAs in both low light and high light. The qE and gene expression phenotypes of spa1-1 are blocked by mutation of CrCO, a B-box Zn-finger transcription factor that is a homolog of CONSTANS, which controls flowering time in plants. CONSTANS-like cis-regulatory sequences were identified proximal to the qE genes, consistent with CrCO acting as a direct activator of qE gene expression. We conclude that SPA1 and CUL4 are components of a conserved E3 ubiquitin ligase that acts upstream of CrCO, whose regulatory function is wired differently in C. reinhardtii to control qE capacity via cis-regulatory CrCO-binding sites at key photoprotection genes.
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Affiliation(s)
- Stéphane T Gabilly
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Christopher R Baker
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Setsuko Wakao
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
| | - Thien Crisanto
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Katharine Guan
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
| | - Ke Bi
- Computational Genomics Resource Laboratory, California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720
| | - Elodie Guiet
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Carmela R Guadagno
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Krishna K Niyogi
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720;
- Howard Hughes Medical Institute, University of California, Berkeley, CA 94720
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
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153
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Abstract
How structurally distinct photoreceptors regulate evolutionarily diverse transcription factors to modulate common photoresponses is an intriguing question in plant biology. In this issue of The EMBO Journal, Lau et al demonstrate that COP1, the substrate receptor of E3 ubiquitin ligase CUL4COP 1- SPA s , interacts with the diverse VP motif-containing transcription factors and photoreceptors via its highly plastic WD40 domain. Light-activated photoreceptors increase their affinity to COP1 to outcompete the COP1-interacting transcription factors, allowing their accumulation and inducing photomorphogenic development of plants.
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Affiliation(s)
- Qin Wang
- Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Chentao Lin
- Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA, USA
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154
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Lau K, Podolec R, Chappuis R, Ulm R, Hothorn M. Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs. EMBO J 2019; 38:e102140. [PMID: 31304983 PMCID: PMC6745501 DOI: 10.15252/embj.2019102140] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/29/2019] [Accepted: 06/07/2019] [Indexed: 12/31/2022] Open
Abstract
Plants sense different parts of the sun's light spectrum using distinct photoreceptors, which signal through the E3 ubiquitin ligase COP1. Here, we analyze why many COP1‐interacting transcription factors and photoreceptors harbor sequence‐divergent Val‐Pro (VP) motifs that bind COP1 with different binding affinities. Crystal structures of the VP motifs of the UV‐B photoreceptor UVR8 and the transcription factor HY5 in complex with COP1, quantitative binding assays, and reverse genetic experiments together suggest that UVR8 and HY5 compete for COP1. Photoactivation of UVR8 leads to high‐affinity cooperative binding of its VP motif and its photosensing core to COP1, preventing COP1 binding to its substrate HY5. UVR8–VP motif chimeras suggest that UV‐B signaling specificity resides in the UVR8 photoreceptor core. Different COP1–VP peptide motif complexes highlight sequence fingerprints required for COP1 targeting. The blue‐light photoreceptors CRY1 and CRY2 also compete with transcription factors for COP1 binding using similar VP motifs. Thus, our work reveals that different photoreceptors and their signaling components compete for COP1 via a conserved mechanism to control different light signaling cascades.
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Affiliation(s)
- Kelvin Lau
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Roman Podolec
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Richard Chappuis
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Roman Ulm
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Michael Hothorn
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
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155
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Hoang QTN, Han YJ, Kim JI. Plant Phytochromes and their Phosphorylation. Int J Mol Sci 2019; 20:ijms20143450. [PMID: 31337079 PMCID: PMC6678601 DOI: 10.3390/ijms20143450] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/10/2019] [Accepted: 07/12/2019] [Indexed: 12/12/2022] Open
Abstract
Extensive research over several decades in plant light signaling mediated by photoreceptors has identified the molecular mechanisms for how phytochromes regulate photomorphogenic development, which includes degradation of phytochrome-interacting factors (PIFs) and inactivation of COP1-SPA complexes with the accumulation of master transcription factors for photomorphogenesis, such as HY5. However, the initial biochemical mechanism for the function of phytochromes has not been fully elucidated. Plant phytochromes have long been known as phosphoproteins, and a few protein phosphatases that directly interact with and dephosphorylate phytochromes have been identified. However, there is no report thus far of a protein kinase that acts on phytochromes. On the other hand, plant phytochromes have been suggested as autophosphorylating serine/threonine protein kinases, proposing that the kinase activity might be important for their functions. Indeed, the autophosphorylation of phytochromes has been reported to play an important role in the regulation of plant light signaling. More recently, evidence that phytochromes function as protein kinases in plant light signaling has been provided using phytochrome mutants displaying reduced kinase activities. In this review, we highlight recent advances in the reversible phosphorylation of phytochromes and their functions as protein kinases in plant light signaling.
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Affiliation(s)
- Quyen T N Hoang
- Department of Biotechnology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 61186, Korea
| | - Yun-Jeong Han
- Department of Biotechnology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 61186, Korea
| | - Jeong-Il Kim
- Department of Biotechnology and Kumho Life Science Laboratory, Chonnam National University, Gwangju 61186, Korea.
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156
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Robson TM, Aphalo PJ, Banaś AK, Barnes PW, Brelsford CC, Jenkins GI, Kotilainen TK, Łabuz J, Martínez-Abaigar J, Morales LO, Neugart S, Pieristè M, Rai N, Vandenbussche F, Jansen MAK. A perspective on ecologically relevant plant-UV research and its practical application. Photochem Photobiol Sci 2019; 18:970-988. [PMID: 30720036 DOI: 10.1039/c8pp00526e] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Plants perceive ultraviolet-B (UV-B) radiation through the UV-B photoreceptor UV RESISTANCE LOCUS 8 (UVR8), and initiate regulatory responses via associated signalling networks, gene expression and metabolic pathways. Various regulatory adaptations to UV-B radiation enable plants to harvest information about fluctuations in UV-B irradiance and spectral composition in natural environments, and to defend themselves against UV-B exposure. Given that UVR8 is present across plant organs and tissues, knowledge of the systemic signalling involved in its activation and function throughout the plant is important for understanding the context of specific responses. Fine-scale understanding of both UV-B irradiance and perception within tissues and cells requires improved application of knowledge about UV-attenuation in leaves and canopies, warranting greater consideration when designing experiments. In this context, reciprocal crosstalk among photoreceptor-induced pathways also needs to be considered, as this appears to produce particularly complex patterns of physiological and morphological response. Through crosstalk, plant responses to UV-B radiation go beyond simply UV-protection or amelioration of damage, but may give cross-protection over a suite of environmental stressors. Overall, there is emerging knowledge showing how information captured by UVR8 is used to regulate molecular and physiological processes, although understanding of upscaling to higher levels of organisation, i.e. organisms, canopies and communities remains poor. Achieving this will require further studies using model plant species beyond Arabidopsis, and that represent a broad range of functional types. More attention should also be given to plants in natural environments in all their complexity, as such studies are needed to acquire an improved understanding of the impact of climate change in the context of plant-UV responses. Furthermore, broadening the scope of experiments into the regulation of plant-UV responses will facilitate the application of UV radiation in commercial plant production. By considering the progress made in plant-UV research, this perspective highlights prescient topics in plant-UV photobiology where future research efforts can profitably be focussed. This perspective also emphasises burgeoning interdisciplinary links that will assist in understanding of UV-B effects across organisational scales and gaps in knowledge that need to be filled so as to achieve an integrated vision of plant responses to UV-radiation.
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Affiliation(s)
- T Matthew Robson
- Organismal and Evolutionary Biology, Viikki Plant Science Centre (ViPS), University of Helsinki, Finland.
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157
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Seo DH, Yoon GM. Light-induced stabilization of ACS contributes to hypocotyl elongation during the dark-to-light transition in Arabidopsis seedlings. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:898-911. [PMID: 30776167 DOI: 10.1111/tpj.14289] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Revised: 02/07/2019] [Accepted: 02/11/2019] [Indexed: 05/25/2023]
Abstract
Hypocotyl growth during seedling emergence is a crucial developmental transition influenced by light and phytohormones such as ethylene. Ethylene and light antagonistically control hypocotyl growth in either continuous light or darkness. However, how ethylene and light regulate hypocotyl growth, including seedling emergence, during the dark-to-light transition remains elusive. Here, we show that ethylene and light cooperatively stimulate a transient increase in hypocotyl growth during the dark-to-light transition via the light-mediated stabilization of 1-aminocyclopropane-1-carboxylic acid (ACC) synthases (ACSs), the rate-limiting enzymes in ethylene biosynthesis. We found that, in contrast to the known inhibitory role of light in hypocotyl growth, light treatment transiently increases hypocotyl growth in wild-type etiolated seedlings. Moreover, ACC, the direct precursor of ethylene, accentuates the effects of light on hypocotyl elongation during the dark-to-light transition. We determined that light leads to the transient elongation of hypocotyls by stabilizing the ACS5 protein during the dark-to-light transition. Furthermore, biochemical analysis of an ACS5 mutant protein bearing an alteration in the C-terminus indicated that light stabilizes ACS5 by inhibiting the degradation mechanism that acts through the C-terminus of ACS5. Our study reveals that plants regulate hypocotyl elongation during seedling establishment by coordinating light-induced ethylene biosynthesis at the post-translational level. Moreover, the stimulatory role of light on hypocotyl growth during the dark-to-light transition provides additional insights into the known inhibitory role of light in hypocotyl development.
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Affiliation(s)
- Dong Hye Seo
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Purdue University Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
| | - Gyeong Mee Yoon
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN, 47907, USA
- Purdue University Center for Plant Biology, Purdue University, West Lafayette, IN, 47907, USA
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158
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Liang T, Yang Y, Liu H. Signal transduction mediated by the plant UV-B photoreceptor UVR8. THE NEW PHYTOLOGIST 2019; 221:1247-1252. [PMID: 30315741 DOI: 10.1111/nph.15469] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/23/2018] [Indexed: 05/20/2023]
Abstract
Contents Summary 1247 I. Introduction 1247 II. The UVR8-COP1 pathway 1248 III. The UVR8-WRKY36 pathway 1248 IV. The UVR8-BES1/BIM1 pathway 1249 V. Other pathways 1250 VI. Conclusion and perspectives 1250 Acknowledgements 1251 References 1251 SUMMARY: Ultraviolet-B (UV-B) light is an intrinsic part of sunlight that has significant effects on plant development and acclimation responses. UVR8 (UV Resistance Locus 8) is the long sought-after UV-B photoreceptor that mediates UV-B light perception and signal transduction. UV-B irradiation induces the monomerization and nuclear accumulation of UVR8 in plant cells to activate the UV-B signaling pathway. The photoactivated UVR8 could transduce UV-B signal via multiple mechanisms to regulate transcription and plant growth. Here, we summarize current understanding of UVR8-mediated UV-B signal transduction pathways, including UVR8-COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC 1) and UVR8-WRKY36 (WRKY DNA-BINDING PROTEIN 36), UVR8-BES1 (BRI1-EMS-SUPPRESSOR1) and BIM1 (BES1-INTERACTING MYC-LIKE 1).
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Affiliation(s)
- Tong Liang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Shanghai, 200032, China
| | - Yu Yang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Shanghai, 200032, China
| | - Hongtao Liu
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences, Shanghai, 200032, China
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159
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Wang W, Chen Q, Botella JR, Guo S. Beyond Light: Insights Into the Role of Constitutively Photomorphogenic1 in Plant Hormonal Signaling. FRONTIERS IN PLANT SCIENCE 2019; 10:557. [PMID: 31156657 PMCID: PMC6532413 DOI: 10.3389/fpls.2019.00557] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 04/12/2019] [Indexed: 05/20/2023]
Abstract
Light is an important environmental factor with profound effects in plant growth and development. Constitutively photomorphogenic1 (COP1) is a vital component of the light signaling pathway as a negative regulator of photomorphogenesis. Although the role of COP1 in light signaling has been firmly established for some time, recent studies have proven that COP1 is also a crucial part of multiple plant hormonal regulatory pathways. In this article, we review the available evidence involving COP1 in hormone signaling, its molecular mechanisms, and its contribution to the complicated regulatory network linking light and plant hormone signaling.
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Affiliation(s)
- Wenjing Wang
- Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, China
- Department of Biology and Food Science, Shangqiu Normal University, Shangqiu, China
| | - Qingbin Chen
- Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, China
- State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, China
| | - José Ramón Botella
- Plant Genetic Engineering Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD, Australia
- *Correspondence: José Ramón Botella,
| | - Siyi Guo
- Key Laboratory of Plant Stress Biology, School of Life Sciences, Henan University, Kaifeng, China
- State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng, China
- Siyi Guo,
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160
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Dolgikh VA, Pukhovaya EM, Zemlyanskaya EV. Shaping Ethylene Response: The Role of EIN3/EIL1 Transcription Factors. FRONTIERS IN PLANT SCIENCE 2019; 10:1030. [PMID: 31507622 PMCID: PMC6718143 DOI: 10.3389/fpls.2019.01030] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/23/2019] [Indexed: 05/05/2023]
Abstract
EIN3/EIL1 transcription factors are the key regulators of ethylene signaling that sustain a variety of plant responses to ethylene. Since ethylene regulates multiple aspects of plant development and stress responses, its signaling outcome needs proper modulation depending on the spatiotemporal and environmental conditions. In this review, we summarize recent advances on the molecular mechanisms that underlie EIN3/EIL1-directed ethylene signaling in Arabidopsis. We focus on the role of EIN3/EIL1 in tuning transcriptional regulation of ethylene response in time and space. Besides, we consider the role of EIN3/EIL1-independent regulation of ethylene signaling.
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Affiliation(s)
- Vladislav A. Dolgikh
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Evgeniya M. Pukhovaya
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
| | - Elena V. Zemlyanskaya
- Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, Russia
- Department of Natural Sciences, Novosibirsk State University, Novosibirsk, Russia
- *Correspondence: Elena V. Zemlyanskaya,
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161
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Lee BD, Cha JY, Kim MR, Shin GI, Paek NC, Kim WY. Light-dependent suppression of COP1 multimeric complex formation is determined by the blue-light receptor FKF1 in Arabidopsis. Biochem Biophys Res Commun 2018; 508:191-197. [PMID: 30471853 DOI: 10.1016/j.bbrc.2018.11.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 11/05/2018] [Indexed: 01/12/2023]
Abstract
CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1), a multifunctional E3 ligase protein with many target proteins, is involved in diverse developmental processes throughout the plant's lifecycle, including seed germination, the regulation of circadian rhythms, photomorphogenesis, and the control of flowering time. To function, COP1 must form multimeric complexes with SUPPRESSOR OF PHYA1 (SPA1), i.e., [(COP1)2(SPA1)2] tetramers. We recently reported that the blue-light receptor FKF1 (FLAVIN-BINDING, KELCH REPEAT, F-BOX1) represses COP1 activity by inhibiting its homodimerization, but it is not yet clear whether FKF1 affects the formation of COP1-containing multimeric complexes. To explore this issue, we performed size exclusion chromatography (SEC) of Arabidopsis thaliana proteins and found that the levels and composition of COP1-containing multimeric complexes varied throughout a 24-h period. The levels of 440-669 kDa complexes were dramatically reduced in the late afternoon compared to the morning and at night in wild-type plants. During the daytime, the levels of these complexes were reduced in FKF1-overexpressing plants but not in fkf1-t, a loss-of-function mutant of FKF1, suggesting that FKF1 is closely associated with the destabilization of COP1 multimeric protein complexes in a light-dependent manner. We also analyzed the SEC patterns of COP1 multimeric complexes in transgenic plants overexpressing mutant COP1 variants, including COP1L105A (which forms homodimers) and COP1L170A (which cannot form homodimers), and found that COP1 multimeric complexes were scarce in plants overexpressing COP1L170A. These results indicate that COP1 homodimers serve as basic building blocks that assemble into COP1 multimeric complexes with diverse target proteins. We propose that light-activated FKF1 inhibits COP1 homodimerization, mainly by destabilizing 440-669 kDa COP1 complexes, resulting in the repression of CONSTANS-degrading COP1 activity in the late afternoon in long days, but not in short days, thereby regulating photoperiodic flowering in Arabidopsis.
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Affiliation(s)
- Byoung-Doo Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08829, Republic of Korea
| | - Joon-Yung Cha
- Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Mi Ri Kim
- Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Gyeong-Im Shin
- Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju, 52828, Republic of Korea
| | - Nam-Chon Paek
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, 08829, Republic of Korea.
| | - Woe-Yeon Kim
- Division of Applied Life Science (BK21Plus), PMBBRC & IALS, Gyeongsang National University, Jinju, 52828, Republic of Korea.
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162
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Arongaus AB, Chen S, Pireyre M, Glöckner N, Galvão VC, Albert A, Winkler JB, Fankhauser C, Harter K, Ulm R. Arabidopsis RUP2 represses UVR8-mediated flowering in noninductive photoperiods. Genes Dev 2018; 32:1332-1343. [PMID: 30254107 PMCID: PMC6169840 DOI: 10.1101/gad.318592.118] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 08/17/2018] [Indexed: 12/22/2022]
Abstract
Arongaus et al. show that genetic mutation of REPRESSOR OF UV-B PHOTOMORPHOGENESIS 2 (RUP2) renders the facultative long day plant Arabidopsis thaliana a day-neutral plant (specifically under light conditions that include UV-B radiation) and dependent on the UV RESISTANCE LOCUS 8 (UVR8) UV-B photoreceptor. Plants have evolved complex photoreceptor-controlled mechanisms to sense and respond to seasonal changes in day length. This ability allows plants to optimally time the transition from vegetative growth to flowering. UV-B is an important part intrinsic to sunlight; however, whether and how it affects photoperiodic flowering has remained elusive. Here, we report that, in the presence of UV-B, genetic mutation of REPRESSOR OF UV-B PHOTOMORPHOGENESIS 2 (RUP2) renders the facultative long day plant Arabidopsis thaliana a day-neutral plant and that this phenotype is dependent on the UV RESISTANCE LOCUS 8 (UVR8) UV-B photoreceptor. We provide evidence that the floral repression activity of RUP2 involves direct interaction with CONSTANS, repression of this key activator of flowering, and suppression of FLOWERING LOCUS T transcription. RUP2 therefore functions as an essential repressor of UVR8-mediated induction of flowering under noninductive short day conditions and thus provides a crucial mechanism of photoperiodic flowering control.
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Affiliation(s)
- Adriana B Arongaus
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva 4, Switzerland
| | - Song Chen
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva 4, Switzerland
| | - Marie Pireyre
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva 4, Switzerland
| | - Nina Glöckner
- Department of Plant Physiology, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany
| | - Vinicius C Galvão
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Andreas Albert
- Research Unit Environmental Simulation, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - J Barbro Winkler
- Research Unit Environmental Simulation, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Christian Fankhauser
- Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, 1015 Lausanne, Switzerland
| | - Klaus Harter
- Department of Plant Physiology, Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany
| | - Roman Ulm
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva 4, Switzerland.,Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 1211 Geneva 4, Switzerland
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