1
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Mironov VL. Unknown effects of daily-scale solar activity on the plant growth: Data from 6-year growth monitoring of Sphagnum riparium. PHYSIOLOGIA PLANTARUM 2022; 174:e13733. [PMID: 35699602 DOI: 10.1111/ppl.13733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/02/2022] [Accepted: 06/09/2022] [Indexed: 06/15/2023]
Abstract
The influence of solar activity on plant growth has been studied for over 100 years, however, this phenomenon is still poorly understood on a daily scale. The data from extensive monitoring of the growth of peat moss Sphagnum riparium, which we are conducting in the mires of Karelia (Russia), may shed light on this issue. During the 6 years of observation, 161,190 shoots were measured, and 1075 growth rates were obtained. Considering together the growth rates with the sunspot number and involving data on seasonal temperature, we found previously unknown effects of daily-scale solar activity on plant growth. It was found that the sunspot number weakly but significantly inhibits the growth of Sphagnum. The extreme sunspot number in the 4 days before the growth rate values have a stronger influence. The involvement of temperature data showed that inhibition in growth is observed only in the temperature range from 6.7°C to 15.3°C and disappears beyond these limits. In addition, the data obtained showed that the influence of sunspot number on the growth of Sphagnum is progressively increasing along the gradient from the minimum to the maximum of the 11-year solar cycle. The study provides one of the first results on the effect of solar activity on plant growth on a daily scale. The results expand our knowledge of the biological effects of solar activity. Indirectly, they can also be useful to better our understanding of the ozone layer's involvement in this process.
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Affiliation(s)
- Victor L Mironov
- Institute of Biology of the Karelian Research Centre of the Russian Academy of Sciences, Petrozavodsk, Russia
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2
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Palma CFF, Castro-Alves V, Rosenqvist E, Ottosen CO, Strid Å, Morales LO. Effects of UV radiation on transcript and metabolite accumulation are dependent on monochromatic light background in cucumber. PHYSIOLOGIA PLANTARUM 2021; 173:750-761. [PMID: 34510478 DOI: 10.1111/ppl.13551] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/25/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
During recent years, we have advanced our understanding of plant molecular responses to ultraviolet radiation (UV, 280-400 nm); however, how plants respond to UV radiation under different spectral light qualities is poorly understood. In this study, cucumber plants (Cucumis sativus "Lausanna RZ F1") were grown under monochromatic blue, green, red, and broadband white light in combination with UV radiation. The effects of light quality and UV radiation on acclimatory responses were assessed by measuring transcript accumulation of ELONGATED HYPOCOTYL 5 (HY5), CHALCONE SYNTHASE 2 (CHS2), and LIGHT HARVESTING COMPLEX II (LHCII), and the accumulation of flavonoids and hydroxycinnamic acids in the leaves. The growth light backgrounds differentially regulated gene expression and metabolite accumulation. While HY5 and CHS2 transcripts were induced by blue and white light, LHCII was induced by white and red light. Furthermore, UV radiation antagonized the effects of blue, red, green, and white light on transcript accumulation in a gene-dependent manner. Plants grown under blue light with supplementary UV radiation increased phenylalanine, flavonol disaccharide I and caffeic acid contents compared to those exposed only to blue light. UV radiation also induced the accumulation of flavonol disaccharide I and II, ferulic acid hexose and coumaric acid hexose in plants grown under green light. Our findings provide a further understanding of plant responses to UV radiation in combination with different light spectra and contribute to the design of light recipes for horticultural practices that aim to modify plant metabolism and ultimately improve crop quality.
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Affiliation(s)
| | - Victor Castro-Alves
- School of Science and Technology, Life Science Centre, Örebro University, Örebro, Sweden
| | - Eva Rosenqvist
- Section of Crop Sciences, Institute of Plant and Environmental Sciences, University of Copenhagen, Tåstrup, Denmark
| | | | - Åke Strid
- School of Science and Technology, Life Science Centre, Örebro University, Örebro, Sweden
| | - Luis Orlando Morales
- School of Science and Technology, Life Science Centre, Örebro University, Örebro, Sweden
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3
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Rai N, Morales LO, Aphalo PJ. Perception of solar UV radiation by plants: photoreceptors and mechanisms. PLANT PHYSIOLOGY 2021; 186:1382-1396. [PMID: 33826733 PMCID: PMC8260113 DOI: 10.1093/plphys/kiab162] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 03/25/2021] [Indexed: 05/04/2023]
Abstract
About 95% of the ultraviolet (UV) photons reaching the Earth's surface are UV-A (315-400 nm) photons. Plant responses to UV-A radiation have been less frequently studied than those to UV-B (280-315 nm) radiation. Most previous studies on UV-A radiation have used an unrealistic balance between UV-A, UV-B, and photosynthetically active radiation (PAR). Consequently, results from these studies are difficult to interpret from an ecological perspective, leaving an important gap in our understanding of the perception of solar UV radiation by plants. Previously, it was assumed UV-A/blue photoreceptors, cryptochromes and phototropins mediated photomorphogenic responses to UV-A radiation and "UV-B photoreceptor" UV RESISTANCE LOCUS 8 (UVR8) to UV-B radiation. However, our understanding of how UV-A radiation is perceived by plants has recently improved. Experiments using a realistic balance between UV-B, UV-A, and PAR have demonstrated that UVR8 can play a major role in the perception of both UV-B and short-wavelength UV-A (UV-Asw, 315 to ∼350 nm) radiation. These experiments also showed that UVR8 and cryptochromes jointly regulate gene expression through interactions that alter the relative sensitivity to UV-B, UV-A, and blue wavelengths. Negative feedback loops on the action of these photoreceptors can arise from gene expression, signaling crosstalk, and absorption of UV photons by phenolic metabolites. These interactions explain why exposure to blue light modulates photomorphogenic responses to UV-B and UV-Asw radiation. Future studies will need to distinguish between short and long wavelengths of UV-A radiation and to consider UVR8's role as a UV-B/UV-Asw photoreceptor in sunlight.
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Affiliation(s)
- Neha Rai
- Organismal and Evolutionary Biology, Viikki Plant Science Center (ViPS), Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
- Author for communication: . Present address: Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland
| | - Luis Orlando Morales
- School of Science and Technology, The Life Science Center-Biology, Örebro University, SE-70182 Örebro, Sweden
| | - Pedro José Aphalo
- Organismal and Evolutionary Biology, Viikki Plant Science Center (ViPS), Faculty of Biological and Environmental Sciences, University of Helsinki, 00014 Helsinki, Finland
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4
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Podolec R, Demarsy E, Ulm R. Perception and Signaling of Ultraviolet-B Radiation in Plants. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:793-822. [PMID: 33636992 DOI: 10.1146/annurev-arplant-050718-095946] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ultraviolet-B (UV-B) radiation is an intrinsic fraction of sunlight that plants perceive through the UVR8 photoreceptor. UVR8 is a homodimer in its ground state that monomerizes upon UV-B photon absorption via distinct tryptophan residues. Monomeric UVR8 competitively binds to the substrate binding site of COP1, thus inhibiting its E3 ubiquitin ligase activity against target proteins, which include transcriptional regulators such as HY5. The UVR8-COP1 interaction also leads to the destabilization of PIF bHLH factor family members. Additionally, UVR8 directly interacts with and inhibits the DNA binding of a different set of transcription factors. Each of these UVR8 signaling mechanisms initiates nuclear gene expression changes leading to UV-B-induced photomorphogenesis and acclimation. The two WD40-repeat proteins RUP1 and RUP2 provide negative feedback regulation and inactivate UVR8 by facilitating redimerization. Here, we review the molecular mechanisms of the UVR8 pathway from UV-B perception and signal transduction to gene expression changes and physiological UV-B responses.
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Affiliation(s)
- Roman Podolec
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland; , ,
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland
| | - Emilie Demarsy
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland; , ,
| | - Roman Ulm
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, 1211 Geneva, Switzerland; , ,
- Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, 1211 Geneva, Switzerland
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5
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Takeda J. Molecular Mechanisms of UVR8-Mediated Photomorphogenesis Derived from Revaluation of Action Spectra. Photochem Photobiol 2021; 97:903-910. [PMID: 34097751 DOI: 10.1111/php.13459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 06/03/2021] [Indexed: 11/27/2022]
Abstract
Considering previously reported action spectra and molecular evidence, I propose a hypothetical model for UV RESISTANCE LOCUS8 (UVR8)-mediated photomorphogenesis. Upon UV-B irradiation, a UVR8 dimer dissociates and accumulates in the nucleus and photomorphogenesis begins following two pathways: one in which the UVR8 monomer binds to transcription factor(s) of gene(s) supporting hypocotyl growth to stop gene expression resulting in hypocotyl growth inhibition and the other in which the UVR8 monomer binds both with CONSTITUTIVELY PHOTOMORPHOGENIC1-SUPPRESSOR OF PHYA (COP1-SPA) to release HY5 (referred to as "stabilized") and WRKY DNA-BINDING PROTEIN 36 (WRKY36) on the ELONGATED HYPOCOTYL 5 (HY5) gene to release HY5 transcription, and both HY5 and another UV-B-activated UV-B sensor (denoted the Hyp sensor in this article) through a self-interacting factor (HIF) associates with the HY5 promoter to initiate HY5 transcription, leading to anthocyanin synthesis. These two pathways can be distinguished by action spectra in the UV-B region, with a single peak at 280 nm and two peaks (or a broad peak near 280-300 nm) for the former and the latter, respectively. Expanding the concept to cyanobacteria and other algae, I discuss the evolution of a UV-B sensor in green plants.
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Affiliation(s)
- Junko Takeda
- Laboratory of Applied Microbiology and Biotechnology, Nara Women's University, Nara, Japan
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Rai N, O'Hara A, Farkas D, Safronov O, Ratanasopa K, Wang F, Lindfors AV, Jenkins GI, Lehto T, Salojärvi J, Brosché M, Strid Å, Aphalo PJ, Morales LO. The photoreceptor UVR8 mediates the perception of both UV-B and UV-A wavelengths up to 350 nm of sunlight with responsivity moderated by cryptochromes. PLANT, CELL & ENVIRONMENT 2020; 43:1513-1527. [PMID: 32167576 DOI: 10.1111/pce.13752] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 05/27/2023]
Abstract
The photoreceptors UV RESISTANCE LOCUS 8 (UVR8) and CRYPTOCHROMES 1 and 2 (CRYs) play major roles in the perception of UV-B (280-315 nm) and UV-A/blue radiation (315-500 nm), respectively. However, it is poorly understood how they function in sunlight. The roles of UVR8 and CRYs were assessed in a factorial experiment with Arabidopsis thaliana wild-type and photoreceptor mutants exposed to sunlight for 6 or 12 hr under five types of filters with cut-offs in UV and blue-light regions. Transcriptome-wide responses triggered by UV-B and UV-A wavelengths shorter than 350 nm (UV-Asw ) required UVR8 whereas those induced by blue and UV-A wavelengths longer than 350 nm (UV-Alw ) required CRYs. UVR8 modulated gene expression in response to blue light while lack of CRYs drastically enhanced gene expression in response to UV-B and UV-Asw . These results agree with our estimates of photons absorbed by these photoreceptors in sunlight and with in vitro monomerization of UVR8 by wavelengths up to 335 nm. Motif enrichment analysis predicted complex signaling downstream of UVR8 and CRYs. Our results highlight that it is important to use UV waveband definitions specific to plants' photomorphogenesis as is routinely done in the visible region.
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Affiliation(s)
- Neha Rai
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Andrew O'Hara
- Örebro Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Daniel Farkas
- Örebro Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Omid Safronov
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Khuanpiroon Ratanasopa
- Örebro Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Fang Wang
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Anders V Lindfors
- Meteorological Research, Finnish Meteorological Institute, Helsinki, Finland
| | - Gareth I Jenkins
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Tarja Lehto
- School of Forest Sciences, University of Eastern Finland, Joensuu, Finland
| | - Jarkko Salojärvi
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore
| | - Mikael Brosché
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Åke Strid
- Örebro Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden
| | - Pedro J Aphalo
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
| | - Luis O Morales
- Organismal and Evolutionary Biology, Faculty of Biological and Environmental Sciences, and Viikki Plant Science Centre, University of Helsinki, Helsinki, Finland
- Örebro Life Science Center, School of Science and Technology, Örebro University, Örebro, Sweden
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7
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Yang Y, Zhang L, Chen P, Liang T, Li X, Liu H. UV-B photoreceptor UVR8 interacts with MYB73/MYB77 to regulate auxin responses and lateral root development. EMBO J 2020; 39:e101928. [PMID: 31777974 PMCID: PMC6960441 DOI: 10.15252/embj.2019101928] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 10/21/2019] [Accepted: 10/24/2019] [Indexed: 12/31/2022] Open
Abstract
The UV-B photoreceptor UVR8 mediates multiple UV-B responses in plants, but the function of UVR8 in regulating root development has not previously been investigated. Here, we show that UV-B light inhibits Arabidopsis lateral root growth in a UVR8-dependent manner. Monomeric UVR8 inhibits auxin responses in a tissue-autonomous manner and thereby regulates lateral root growth. Genome-wide gene expression analysis demonstrated that auxin and UV-B irradiation antagonistically regulate auxin-regulated gene expression. We further show that UVR8 physically interacts with MYB73/MYB77 (MYB DOMAIN PROTEIN 73/77) in a UV-B-dependent manner. UVR8 inhibits lateral root development via regulation of MYB73/MYB77. When activated by UV-B light, UVR8 localizes to the nucleus and inhibits the DNA-binding activities of MYB73/MYB77 and directly represses the transcription of their target auxin-responsive genes. Our results demonstrate that UV-B light and UVR8 are critical for both shoot morphogenesis and root development. The UV-B-dependent interaction of UVR8 and MYB73/MYB77 serves as an important module that integrates light and auxin signaling and represents a new UVR8 signaling mechanism in plants.
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Affiliation(s)
- Yu Yang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG)CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and Ecology (SIPPE)Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesShanghaiChina
| | - Libo Zhang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG)CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and Ecology (SIPPE)Chinese Academy of SciencesShanghaiChina
| | - Ping Chen
- National Key Laboratory of Plant Molecular Genetics (NKLPMG)CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and Ecology (SIPPE)Chinese Academy of SciencesShanghaiChina
- The Joint Center for Infection and Immunity between Guangzhou Institute of PediatricsGuangzhou Women and Children's Medical CenterGuangzhouChina
| | - Tong Liang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG)CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and Ecology (SIPPE)Chinese Academy of SciencesShanghaiChina
- University of Chinese Academy of SciencesShanghaiChina
| | - Xuan Li
- National Key Laboratory of Plant Molecular Genetics (NKLPMG)CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and Ecology (SIPPE)Chinese Academy of SciencesShanghaiChina
| | - Hongtao Liu
- National Key Laboratory of Plant Molecular Genetics (NKLPMG)CAS Center for Excellence in Molecular Plant SciencesInstitute of Plant Physiology and Ecology (SIPPE)Chinese Academy of SciencesShanghaiChina
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8
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Landi M, Zivcak M, Sytar O, Brestic M, Allakhverdiev SI. Plasticity of photosynthetic processes and the accumulation of secondary metabolites in plants in response to monochromatic light environments: A review. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1861:148131. [PMID: 31816291 DOI: 10.1016/j.bbabio.2019.148131] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 10/17/2019] [Accepted: 11/28/2019] [Indexed: 01/08/2023]
Abstract
Light spectra significantly influence plant metabolism, growth and development. Here, we review the effects of monochromatic blue, red and green light compared to those of multispectral light sources on the morpho-anatomical, photosynthetic and molecular traits of herbaceous plants. Emphasis is given to the effect of light spectra on the accumulation of secondary metabolites, which are important bioactive phytochemicals that determine the nutritional quality of vegetables. Overall, blue light may promote the accumulation of phenylpropanoid-based compounds without substantially affecting plant morpho-anatomical traits compared to the effects of white light. Red light, conversely, strongly alters plant morphology and physiology compared to that under white light without showing a consistent positive effect on secondary metabolism. Due to species-specific effects and the small shifts in the spectral band within the same color that can substantially affect plant growth and metabolism, it is conceivable that monochromatic light significantly affects not only plant photosynthetic performance but also the "quality" of plants by modulating the biosynthesis of photoprotective compounds.
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Affiliation(s)
- Marco Landi
- Department of Agriculture, Food and Environment, University of Pisa, Italy
| | - Marek Zivcak
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic.
| | - Oksana Sytar
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic
| | - Marian Brestic
- Department of Plant Physiology, Slovak University of Agriculture, Nitra, Slovak Republic; Department of Botany and Plant Physiology, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences, 16500 Prague, Czech Republic
| | - Suleyman I Allakhverdiev
- K.A. Timiryazev Institute of Plant Physiology, Russian Academy of Sciences, Moscow, Russia; Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Moscow Region, Russia; Department of Plant Physiology, M.V. Lomonosov Moscow State University, Moscow, Russia; Department of Molecular and Cell Biology, Moscow Institute of Physics and Technology, Institutsky lane 9, Dolgoprudny, Moscow Region, Russia; Institute of Molecular Biology and Biotechnology, Azerbaijan National Academy of Sciences, Baku, Azerbaijan; King Saud University, Riyadh, Saudi Arabia.
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9
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Llabata P, Richter J, Faus I, Słomiňska-Durdasiak K, Zeh LH, Gadea J, Hauser MT. Involvement of the eIF2α Kinase GCN2 in UV-B Responses. FRONTIERS IN PLANT SCIENCE 2019; 10:1492. [PMID: 31850012 PMCID: PMC6892979 DOI: 10.3389/fpls.2019.01492] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/28/2019] [Indexed: 05/12/2023]
Abstract
GCN2 (general control nonrepressed 2) is a serine/threonine-protein kinase that regulates translation in response to stressors such as amino acid and purin deprivation, cold shock, wounding, cadmium, and UV-C exposure. Activated GCN2 phosphorylates the α-subunit of the eukaryotic initiation factor 2 (eIF2) leading to a drastic inhibition of protein synthesis and shifting translation to specific mRNAs. To investigate the role of GCN2 in responses to UV-B radiation its activity was analyzed through eIF2α phosphorylation assays in mutants of the specific UV-B and stress signaling pathways of Arabidopsis thaliana. EIF2α phosphorylation was detectable 30 min after UV-B exposure, independent of the UV-B photoreceptor UV RESISTANCE LOCUS8 and its downstream signaling components. GCN2 dependent phosphorylation of eIF2α was also detectable in mutants of the stress related MAP kinases, MPK3 and MPK6 and their negative regulator map kinase phosphatase1 (MKP1). Transcription of downstream components of the UV-B signaling pathway, the Chalcone synthase (CHS) was constitutively higher in gcn2-1 compared to wildtype and further increased upon UV-B while GLUTATHIONE PEROXIDASE7 (GPX7) behaved similarly to wildtype. The UVR8 independent FAD-LINKED OXIDOREDUCTASE (FADox) had a lower basal expression in gcn2-1 which was increased upon UV-B. Since high fluence rates of UV-B induce DNA damage the expression of the RAS ASSOCIATED WITH DIABETES PROTEIN51 (RAD51) was quantified before and after UV-B. While the basal expression was similar to wildtype it was significantly less induced upon UV-B in the gcn2-1 mutant. This expression pattern correlates with the finding that gcn2 mutants develop less cyclobutane pyrimidine dimers after UV-B exposure. Quantification of translation with the puromycination assay revealed that gcn2 mutants have an increased rate of translation which was also higher upon UV-B. Growth of gcn2 mutants to chronic UV-B exposure supports GCN2's role as a negative regulator of UV-B responses. The elevated resistance of gcn2 mutants towards repeated UV-B exposure points to a critical role of GCN2 in the regulation of translation upon UV-B.
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Affiliation(s)
- Paula Llabata
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV), Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Valencia, Spain
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
- Bellvitge Biomedical Research Institute IDIBELL, Barcelona, Spain
| | - Julia Richter
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Isabel Faus
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV), Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Valencia, Spain
| | - Karolina Słomiňska-Durdasiak
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Lukas Hubert Zeh
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
| | - Jose Gadea
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia (UPV), Consejo Superior de Investigaciones Científicas (CSIC), Ciudad Politécnica de la Innovación (CPI), Valencia, Spain
| | - Marie-Theres Hauser
- Institute of Applied Genetics and Cell Biology, BOKU University of Natural Resources and Life Sciences, Vienna, Austria
- *Correspondence: Marie-Theres Hauser,
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10
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Fraikin GY, Belenikina NS, Rubin AB. Damaging and Defense Processes Induced in Plant Cells by UVB Radiation. BIOL BULL+ 2018. [DOI: 10.1134/s1062359018060031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Fraikin GY. Signaling Mechanisms Regulating Diverse Plant Cell Responses to UVB Radiation. BIOCHEMISTRY (MOSCOW) 2018; 83:787-794. [PMID: 30200863 DOI: 10.1134/s0006297918070027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
UVB radiation (290-320 nm) causes diverse effects in plant cells that vary with the fluence rate of exposure. High fluence rates of UVB radiation cause damage to DNA and formation of reactive oxygen species in mitochondria and chloroplasts, which lead to oxidation of membrane proteins and lipids and inhibition of cellular functions. In response to oxidative stress, mitochondrial transmembrane potential dissipates, resulting in cytochrome c release and activation of metacaspases. This leads to the apoptosis-like cell death. The signaling mechanism based on UVB DNA damage includes checkpoint activation, cell-cycle arrest, and finally programmed cell death with characteristic DNA fragmentation and morphological hallmarks typical of apoptotic cells. Recently, it was shown that among the components of this signaling mechanism the transcriptional factor SOG1 (suppressor of gamma response 1) plays a key role in regulation of programmed cell death in plants. In contrast to its damaging effects, UVB radiation at low fluence rates can act as a regulatory signal that is specifically perceived by plants to promote acclimation and survival in sunlight. The protective action of UVB is based on expression of various genes, including those encoding flavonoid synthesis enzymes that provide a UVB-absorbing sunscreen in epidermal tissues and DNA photorepair enzymes. These processes are mediated by the UVB photoreceptor UVR8, which has been recently characterized at the molecular level. Now progress is made in uncovering the UVR8-mediated signaling pathway mechanism in the context of UVB photon perception and revealing the biochemical components of the early stages of light signal transduction. In this review, attention is focused on the achievements in studying these UVB-induced signaling processes.
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Affiliation(s)
- G Ya Fraikin
- Lomonosov Moscow State University, Moscow, 119991, Russia.
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12
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Gao L, Li Y, Shen Z, Han R. Responses of He-Ne laser on agronomic traits and the crosstalk between UVR8 signaling and phytochrome B signaling pathway in Arabidopsis thaliana subjected to supplementary ultraviolet-B (UV-B) stress. PROTOPLASMA 2018; 255:761-771. [PMID: 29138939 DOI: 10.1007/s00709-017-1184-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Accepted: 11/07/2017] [Indexed: 06/07/2023]
Abstract
UV-B acclimation effects and UV-B damage repair induced by a 632.8-nm He-Ne laser were investigated in Arabidopsis thaliana plants in response to supplementary UV-B stress. There was an increasing trend in growth parameters in the combination-treated plants with He-Ne laser and UV-B light compared to those stressed with enhanced UV-B light alone during different developmental stages of plants. The photosynthetic efficiency (Pn) and survival rates of seedlings were significantly higher in the combination treatments than UV-B stress alone. The expression of UVR8, phytochrome B (PhyB), and their mediated signal responsive genes such as COP1, HY5, and CHS were also significantly upregulated in plants with the laser irradiation compared with other groups without the laser. Levels of flavonol accumulation in leaves and capsule yield of He-Ne laser-treated plants were increased. The phyB-9 mutants were more sensitive to enhanced UV-B stress and had no obvious improvements in plant phenotypic development and physiological damage caused by enhanced UV-B stress after He-Ne laser irradiation. Our results suggested that UVR8 and its mediated signaling pathway via interaction with COP1 can be induced by He-Ne laser, and these processes were dependent on cytoplasmic PhyB levels in plant cells, which might be one of the most important mechanisms of He-Ne laser on UV-B protection and UV-B damage repair. These current data have also elucidated that the biostimulatory effects of He-Ne laser on Arabidopsis thaliana plants would happen not only during the early growth stage but also during the entire late developmental stage.
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Affiliation(s)
- Limei Gao
- Modern College of Humanities and Sciences, Shanxi Normal University, Linfen, 041004, China.
- College of Life Science, Shanxi Normal University, Linfen, 041004, China.
- Higher Education Key Laboratory of Plant Molecular and Environmental Stress Response, Shanxi Normal University, Linfen, 041004, China.
| | - Yongfeng Li
- Higher Education Key Laboratory of Plant Molecular and Environmental Stress Response, Shanxi Normal University, Linfen, 041004, China
- Analysis and Testing Center, Shanxi Normal University, Linfen, 041004, China
| | - Zhihua Shen
- College of Life Science, Shanxi Normal University, Linfen, 041004, China
- Higher Education Key Laboratory of Plant Molecular and Environmental Stress Response, Shanxi Normal University, Linfen, 041004, China
| | - Rong Han
- College of Life Science, Shanxi Normal University, Linfen, 041004, China
- Higher Education Key Laboratory of Plant Molecular and Environmental Stress Response, Shanxi Normal University, Linfen, 041004, China
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13
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Yang Y, Liang T, Zhang L, Shao K, Gu X, Shang R, Shi N, Li X, Zhang P, Liu H. UVR8 interacts with WRKY36 to regulate HY5 transcription and hypocotyl elongation in Arabidopsis. NATURE PLANTS 2018; 4:98-107. [PMID: 29379156 DOI: 10.1038/s41477-017-0099-0] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 12/27/2017] [Indexed: 05/20/2023]
Abstract
UV RESISTANCE LOCUS 8 (UVR8) is an ultraviolet-B (UVB) radiation photoreceptor that mediates light responses in plants. How plant UVR8 acts in response to UVB light is not well understood. Here, we report the identification and characterization of the Arabidopsis WRKY DNA-BINDING PROTEIN 36 (WRKY36) protein. WRKY36 interacts with UVR8 in yeast and Arabidopsis cells and it promotes hypocotyl elongation by inhibiting HY5 transcription. Inhibition of hypocotyl elongation under UVB requires the inhibition of WRKY36. WRKY36 binds to the W-box motif of the HY5 promoter to inhibit its transcription, while nuclear localized UVR8 directly interacts with WRKY36 to inhibit WRKY36-DNA binding both in vitro and in vivo, leading to the release of inhibition of HY5 transcription. These results indicate that WRKY36 is a negative regulator of HY5 and that UVB represses WRKY36 via UVR8 to promote the transcription of HY5 and photomorphogenesis. The UVR8-WRKY36 interaction in the nucleus represents a novel mechanism of early UVR8 signal transduction in Arabidopsis.
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Affiliation(s)
- Yu Yang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- Shanghai College of Life Science, University of Chinese Academy of Sciences, Shanghai, China
| | - Tong Liang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- Shanghai College of Life Science, University of Chinese Academy of Sciences, Shanghai, China
| | - Libo Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Kai Shao
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- Shanghai College of Life Science, University of Chinese Academy of Sciences, Shanghai, China
| | - Xingxing Gu
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- Shanghai College of Life Science, University of Chinese Academy of Sciences, Shanghai, China
| | - Ruixin Shang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- Shanghai College of Life Science, University of Chinese Academy of Sciences, Shanghai, China
| | - Nan Shi
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Xu Li
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Peng Zhang
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Hongtao Liu
- National Key Laboratory of Plant Molecular Genetics, Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
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14
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Díaz-Ramos LA, O'Hara A, Kanagarajan S, Farkas D, Strid Å, Jenkins GI. Difference in the action spectra for UVR8 monomerisation and HY5 transcript accumulation in Arabidopsis. Photochem Photobiol Sci 2018; 17:1108-1117. [DOI: 10.1039/c8pp00138c] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The action spectrum for monomerisation of the plant UV-B photoreceptor UVR8 peaks at a shorter wavelength than that for HY5 transcript accumulation, mediated by UVR8, in the same tissue.
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Affiliation(s)
- L. Aranzazú Díaz-Ramos
- Institute of Molecular
- Cell and Systems Biology
- College of Medical
- Veterinary and Life Sciences
- Bower Building
| | - Andrew O'Hara
- Institute of Molecular
- Cell and Systems Biology
- College of Medical
- Veterinary and Life Sciences
- Bower Building
| | - Selvaraju Kanagarajan
- School of Science & Technology
- Örebro Life Science Center
- Örebro University
- SE-70182 Örebro
- Sweden
| | - Daniel Farkas
- School of Science & Technology
- Örebro Life Science Center
- Örebro University
- SE-70182 Örebro
- Sweden
| | - Åke Strid
- School of Science & Technology
- Örebro Life Science Center
- Örebro University
- SE-70182 Örebro
- Sweden
| | - Gareth I. Jenkins
- Institute of Molecular
- Cell and Systems Biology
- College of Medical
- Veterinary and Life Sciences
- Bower Building
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15
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Dotto M, Casati P. Developmental reprogramming by UV-B radiation in plants. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 264:96-101. [PMID: 28969807 DOI: 10.1016/j.plantsci.2017.09.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/27/2017] [Accepted: 09/01/2017] [Indexed: 05/08/2023]
Abstract
Plants are extremely plastic organisms with the ability to adapt and respond to the changing environmental conditions surrounding them. Sunlight is one of the main resources for plants, both as a primary energy source for photosynthesis and as a stimulus that regulates different aspects of their growth and development. UV-B comprises wavelengths that correspond to a high energy region of the solar spectrum capable of reaching the biosphere, influencing plant growth. It is currently believed that plants are able to acclimate when growing under the influence of this radiation and perceive it as a signal, without stress signs. Nonetheless, many UV-B induced changes are elicited after DNA damage occurs as a consequence of exposure. In this review we focus on the influence of UV-B on leaf, flower and root development and emphasize the limited understanding of the molecular mechanisms for most of this developmental processes affected by UV-B documented over the years of research in this area.
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Affiliation(s)
- Marcela Dotto
- Facultad de Ciencias Agrarias, Universidad Nacional del Litoral, 3080, Esperanza, Santa Fe, Argentina.
| | - Paula Casati
- Centro de Estudios Fotosintéticos y Bioquímicos, Universidad Nacional de Rosario, 2000, Rosario, Santa Fe, Argentina.
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16
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Jenkins GI. Photomorphogenic responses to ultraviolet-B light. PLANT, CELL & ENVIRONMENT 2017; 40:2544-2557. [PMID: 28183154 DOI: 10.1111/pce.12934] [Citation(s) in RCA: 120] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Revised: 02/03/2017] [Accepted: 02/04/2017] [Indexed: 05/18/2023]
Abstract
Exposure to ultraviolet B (UV-B) light regulates numerous aspects of plant metabolism, morphology and physiology through the differential expression of hundreds of genes. Photomorphogenic responses to UV-B are mediated by the photoreceptor UV RESISTANCE LOCUS8 (UVR8). Considerable progress has been made in understanding UVR8 action: the structural basis of photoreceptor function, how interaction with CONSTITUTIVELY PHOTOMORPHOGENIC 1 initiates signaling and how REPRESSOR OF UV-B PHOTOMORPHOGENESIS proteins negatively regulate UVR8 action. In addition, recent research shows that UVR8 mediates several responses through interaction with other signaling pathways, in particular auxin signaling. Nevertheless, many aspects of UVR8 action remain poorly understood. Most research to date has been undertaken with Arabidopsis, and it is important to explore the functions and regulation of UVR8 in diverse plant species. Furthermore, it is essential to understand how UVR8, and UV-B signaling in general, regulates processes under natural growth conditions. Ultraviolet B regulates the expression of many genes through UVR8-independent pathways, but the activity and importance of these pathways in plants growing in sunlight are poorly understood.
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Affiliation(s)
- Gareth I Jenkins
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
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17
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Tohge T, Fernie AR. Leveraging Natural Variance towards Enhanced Understanding of Phytochemical Sunscreens. TRENDS IN PLANT SCIENCE 2017; 22:308-315. [PMID: 28173981 DOI: 10.1016/j.tplants.2017.01.003] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 12/23/2016] [Accepted: 01/08/2017] [Indexed: 05/28/2023]
Abstract
The dependency of plants on sunlight renders exposure to UV a constant hazard. Light of this wavelength is damaging to proteins, RNA, and DNA, with damage to the latter resulting in a high mutagenic potential. To acclimate to environmental changes in light wavelengths and intensity, plants accumulate the production of UV-B-protectant phytochemicals, such as flavonoids and vitamins. Here, we review current and emerging knowledge concerning the biochemical response of plants to UV-B exposure. We additionally outline our opinion that the adoption of broad natural variance represents a powerful strategy by which to identify both novel UV-B-relevant metabolites and the genes regulating their abundance. Finally, we discuss how such information may guide future metabolic engineering strategies aimed at producing stress-tolerant plants.
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Affiliation(s)
- Takayuki Tohge
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany.
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18
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Verdaguer D, Jansen MAK, Llorens L, Morales LO, Neugart S. UV-A radiation effects on higher plants: Exploring the known unknown. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2017; 255:72-81. [PMID: 28131343 DOI: 10.1016/j.plantsci.2016.11.014] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 11/28/2016] [Accepted: 11/29/2016] [Indexed: 05/02/2023]
Abstract
Ultraviolet-A radiation (UV-A: 315-400nm) is a component of solar radiation that exerts a wide range of physiological responses in plants. Currently, field attenuation experiments are the most reliable source of information on the effects of UV-A. Common plant responses to UV-A include both inhibitory and stimulatory effects on biomass accumulation and morphology. UV-A effects on biomass accumulation can differ from those on root: shoot ratio, and distinct responses are described for different leaf tissues. Inhibitory and enhancing effects of UV-A on photosynthesis are also analysed, as well as activation of photoprotective responses, including UV-absorbing pigments. UV-A-induced leaf flavonoids are highly compound-specific and species-dependent. Many of the effects on growth and development exerted by UV-A are distinct to those triggered by UV-B and vary considerably in terms of the direction the response takes. Such differences may reflect diverse UV-perception mechanisms with multiple photoreceptors operating in the UV-A range and/or variations in the experimental approaches used. This review highlights a role that various photoreceptors (UVR8, phototropins, phytochromes and cryptochromes) may play in plant responses to UV-A when dose, wavelength and other conditions are taken into account.
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Affiliation(s)
- Dolors Verdaguer
- Environmental Sciences Department, Faculty of Sciences, University of Girona, Campus de Montilivi, C/Maria Aurèlia Capmany I Farnés, 69, E-17003 Girona, Spain.
| | - Marcel A K Jansen
- School of Biological, Earth and Environmental Sciences, University College Cork, Distillery Field, North Mall, Cork, Ireland.
| | - Laura Llorens
- Environmental Sciences Department, Faculty of Sciences, University of Girona, Campus de Montilivi, C/Maria Aurèlia Capmany I Farnés, 69, E-17003 Girona, Spain.
| | - Luis O Morales
- Division of Plant Biology, Department of Biosciences, Viikki Plant Science Center, University of Helsinki, FI-00014 Helsinki, Finland.
| | - Susanne Neugart
- Leibniz-Institute of Vegetable and Ornamental Crops Grossbeeren/Erfurt e.V., Theodor-Echtermeyer-Weg 1, 14979, Grossbeeren, Germany.
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19
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Affiliation(s)
- Phillip A. Davis
- Stockbridge Technology Centre Cawood Selby North Yorkshire YO8 3TZ UK
| | - Claire Burns
- Stockbridge Technology Centre Cawood Selby North Yorkshire YO8 3TZ UK
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20
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Heilmann M, Velanis CN, Cloix C, Smith BO, Christie JM, Jenkins GI. Dimer/monomer status and in vivo function of salt-bridge mutants of the plant UV-B photoreceptor UVR8. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:71-81. [PMID: 27385642 PMCID: PMC5091643 DOI: 10.1111/tpj.13260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/12/2015] [Revised: 06/24/2016] [Accepted: 06/30/2016] [Indexed: 05/05/2023]
Abstract
UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor for ultraviolet-B (UV-B) light that initiates photomorphogenic responses in plants. UV-B photoreception causes rapid dissociation of dimeric UVR8 into monomers that interact with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1) to initiate signal transduction. Experiments with purified UVR8 show that the dimer is maintained by salt-bridge interactions between specific charged amino acids across the dimer interface. However, little is known about the importance of these charged amino acids in determining dimer/monomer status and UVR8 function in plants. Here we evaluate the use of different methods to examine dimer/monomer status of UVR8 and show that mutations of several salt-bridge amino acids affect dimer/monomer status, interaction with COP1 and photoreceptor function of UVR8 in vivo. In particular, the salt-bridges formed between arginine 286 and aspartates 96 and 107 are key to dimer formation. Mutation of arginine 286 to alanine impairs dimer formation, interaction with COP1 and function in vivo, whereas mutation to lysine gives a weakened dimer that is functional in vivo, indicating the importance of the positive charge of the arginine/lysine residue for dimer formation. Notably, a UVR8 mutant in which aspartates 96 and 107 are conservatively mutated to asparagine is strongly impaired in dimer formation but mediates UV-B responses in vivo with a similar dose-response relationship to wild-type. The UV-B responsiveness of this mutant does not correlate with dimer formation and monomerisation, indicating that monomeric UVR8 has the potential for UV-B photoreception, initiating signal transduction and responses in plants.
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Affiliation(s)
- Monika Heilmann
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
| | - Christos N Velanis
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
| | - Catherine Cloix
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
| | - Brian O Smith
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
| | - John M Christie
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK
| | - Gareth I Jenkins
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bower Building, Glasgow, G12 8QQ, UK.
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21
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Findlay KMW, Jenkins GI. Regulation of UVR8 photoreceptor dimer/monomer photo-equilibrium in Arabidopsis plants grown under photoperiodic conditions. PLANT, CELL & ENVIRONMENT 2016; 39:1706-14. [PMID: 26864532 PMCID: PMC5103188 DOI: 10.1111/pce.12724] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/30/2016] [Indexed: 05/09/2023]
Abstract
The UV RESISTANCE LOCUS 8 (UVR8) photoreceptor specifically mediates photomorphogenic responses to UV-B. Photoreception induces dissociation of dimeric UVR8 into monomers to initiate responses. However, the regulation of dimer/monomer status in plants growing under photoperiodic conditions has not been examined. Here we show that UVR8 establishes a dimer/monomer photo-equilibrium in plants growing in diurnal photoperiods in both controlled environments and natural daylight. The photo-equilibrium is determined by the relative rates of photoreception and dark-reversion to the dimer. Experiments with mutants in REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 (RUP1) and RUP2 show that these proteins are crucial in regulating the photo-equilibrium because they promote reversion to the dimer. In plants growing in daylight, the UVR8 photo-equilibrium is most strongly correlated with low ambient fluence rates of UV-B (up to 1.5 μmol m(-2) s(-1) ), rather than higher fluence rates or the amount of photosynthetically active radiation. In addition, the rate of reversion of monomer to dimer is reduced at lower temperatures, promoting an increase in the relative level of monomer at approximately 8-10 °C. Thus, UVR8 does not behave like a simple UV-B switch under photoperiodic growth conditions but establishes a dimer/monomer photo-equilibrium that is regulated by UV-B and also influenced by temperature.
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Affiliation(s)
- Kirsten M W Findlay
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Gareth I Jenkins
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Bower Building, University of Glasgow, Glasgow, G12 8QQ, UK
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22
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Miyamori T, Nakasone Y, Hitomi K, Christie JM, Getzoff ED, Terazima M. Reaction dynamics of the UV-B photosensor UVR8. Photochem Photobiol Sci 2016; 14:995-1004. [PMID: 25811405 DOI: 10.1039/c5pp00012b] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
UVR8 is a recently discovered ultraviolet-B (UV-B) photoreceptor protein identified in plants and algae. In the dark state, UVR8 exists as a homodimer, whereas UV-B irradiation induces UVR8 monomerization and initiation of signaling. Although the biological functions of UVR8 have been studied, the fundamental reaction mechanism and associated kinetics have not yet been fully elucidated. Here, we used the transient grating method to determine the reaction dynamics of UVR8 monomerization based on its diffusion coefficient. We found that the UVR8 photodissociation reaction proceeds in three stages: (i) photoexcitation of cross-dimer tryptophan (Trp) pyramids; (ii) an initial conformational change with a time constant of 50 ms; and (iii) dimer dissociation with a time constant of 200 ms. We identified W285 as the key Trp residue responsible for initiating this photoreaction. Although the C-terminus of UVR8 is essential for biological interactions and signaling via downstream components such as COP1, no obvious differences were detected between the photoreactions of wild-type UVR8 (amino acids 1-440) and a mutant lacking the C-terminus (amino acids 1-383). This similarity indicates that the conformational change associated with stage ii cannot primarily be attributed to this region. A UV-B-driven conformational change with a time constant of 50 ms was also detected in the monomeric mutants of UVR8. Dimer recovery following monomerization, as measured by circular dichroism spectroscopy, was decreased under oxygen-purged conditions, suggesting that redox reactivity is a key factor contributing to the UVR8 oligomeric state.
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Affiliation(s)
- Takaaki Miyamori
- Department of Chemistry, Graduate School of Science, Kyoto University, Oiwake, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan.
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23
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Xie L, Lang-Mladek C, Richter J, Nigam N, Hauser MT. UV-B induction of the E3 ligase ARIADNE12 depends on CONSTITUTIVELY PHOTOMORPHOGENIC 1. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2015; 93:18-28. [PMID: 25817546 PMCID: PMC4503874 DOI: 10.1016/j.plaphy.2015.03.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Accepted: 03/20/2015] [Indexed: 05/05/2023]
Abstract
The UV-B inducible ARIADNE12 (ARI12) gene of Arabidopsis thaliana is a member of the RING-between-RING (RBR) family of E3 ubiquitin ligases for which a novel ubiquitination mechanism was identified in mammalian homologs. This RING-HECT hybrid mechanism needs a conserved cysteine which is replaced by serine in ARI12 and might affect the E3 ubiquitin ligase activity. We have shown that under photomorphogenic UV-B, ARI12 is a downstream target of the classical ultraviolet B (UV-B) UV Resistance Locus 8 (UVR8) pathway. However, under high fluence rate of UV-B ARI12 was induced independently of UVR8 and the UV-A/blue light and red/far-red photoreceptors. A key component of several light signaling pathways is Constitutively Photomorphogenic 1 (COP1). Upon UV-B COP1 is trapped in the nucleus through interaction with UVR8 permitting the activation of genes that regulate the biosynthesis of UV-B protective metabolites and growth adaptations. To clarify the role of COP1 in the regulation of ARI12 mRNA expression and ARI12 protein stability, localization and interaction with COP1 was assessed with and without UV-B. We found that COP1 controls ARI12 in white light, low and high fluence rate of UV-B. Furthermore we show that ARI12 is indeed an E3 ubiquitin ligase which is mono-ubiquitinated, a prerequisite for the RING-HECT hybrid mechanism. Finally, genetic analyses with transgenes expressing a genomic pmARI12:ARI12-GFP construct confirm the epistatic interaction between COP1 and ARI12 in growth responses to high fluence rate UV-B.
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Affiliation(s)
- Lisi Xie
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Christina Lang-Mladek
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Julia Richter
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Neha Nigam
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
| | - Marie-Theres Hauser
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
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24
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Xu W, Dubos C, Lepiniec L. Transcriptional control of flavonoid biosynthesis by MYB-bHLH-WDR complexes. TRENDS IN PLANT SCIENCE 2015; 20:176-85. [PMID: 25577424 DOI: 10.1016/j.tplants.2014.12.001] [Citation(s) in RCA: 909] [Impact Index Per Article: 101.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Revised: 11/21/2014] [Accepted: 12/10/2014] [Indexed: 05/18/2023]
Abstract
Flavonoids are widely known for the colors they confer to plant tissues, their contribution to plant fitness and health benefits, and impact on food quality. As convenient biological markers, flavonoids have been instrumental in major genetic and epigenetic discoveries. We review recent advances in the characterization of the underlying regulatory mechanisms of flavonoid biosynthesis, with a special focus on the MBW (MYB-bHLH-WDR) protein complexes. These proteins are well conserved in higher plants. They participate in different types of controls ranging from fine-tuned transcriptional regulation by environmental factors to the initiation of the flavonoid biosynthesis pathway by positive regulatory feedback. The MBW protein complexes provide interesting models for investigating developmentally or environmentally controlled transcriptional regulatory networks.
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Affiliation(s)
- Wenjia Xu
- Institut National de la Recherche Agronomique (INRA) Institut Jean-Pierre Bourgin, ERL-CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, ERL-CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France
| | - Christian Dubos
- INRA and Centre National de la Recherche Scientifique (CNRS) SupAgro-M, Université Montpellier 2 (UM2), Biochimie et Physiologie Moléculaire des Plantes, 2 place Viala, 34060 Montpellier CEDEX 1, France.
| | - Loïc Lepiniec
- Institut National de la Recherche Agronomique (INRA) Institut Jean-Pierre Bourgin, ERL-CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, ERL-CNRS 3559, Saclay Plant Sciences, RD10, 78026 Versailles, France.
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25
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Wu Q, Huang B, Niehaus TA, Yang X, Fan J, Zhang RQ. The role of tryptophans in the UV-B absorption of a UVR8 photoreceptor – a computational study. Phys Chem Chem Phys 2015; 17:10786-94. [DOI: 10.1039/c4cp06073c] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Absorption spectra of different amino acid models of UVR8.
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Affiliation(s)
- Qi Wu
- Department of Physics and Materials Science
- City University of Hong Kong
- Hong Kong SAR
- China
| | - Bolong Huang
- Department of Physics and Materials Science
- City University of Hong Kong
- Hong Kong SAR
- China
| | - T. A. Niehaus
- Institute I – Theoretical Physics
- University of Regensburg
- D-93040 Regensburg
- Germany
| | - Xiaojing Yang
- Department of Chemistry
- University of Illinois at Chicago
- Chicago
- USA
| | - Jun Fan
- Department of Physics and Materials Science
- City University of Hong Kong
- Hong Kong SAR
- China
| | - Rui-Qin Zhang
- Department of Physics and Materials Science
- City University of Hong Kong
- Hong Kong SAR
- China
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26
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Structure and function of the UV-B photoreceptor UVR8. Curr Opin Struct Biol 2014; 29:52-7. [DOI: 10.1016/j.sbi.2014.09.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 09/01/2014] [Accepted: 09/11/2014] [Indexed: 11/18/2022]
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27
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Binkert M, Kozma-Bognár L, Terecskei K, De Veylder L, Nagy F, Ulm R. UV-B-responsive association of the Arabidopsis bZIP transcription factor ELONGATED HYPOCOTYL5 with target genes, including its own promoter. THE PLANT CELL 2014; 26:4200-13. [PMID: 25351492 PMCID: PMC4247584 DOI: 10.1105/tpc.114.130716] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 09/18/2014] [Accepted: 10/13/2014] [Indexed: 05/18/2023]
Abstract
In plants subjected to UV-B radiation, responses are activated that minimize damage caused by UV-B. The bZIP transcription factor ELONGATED HYPOCOTYL5 (HY5) acts downstream of the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8) and promotes UV-B-induced photomorphogenesis and acclimation. Expression of HY5 is induced by UV-B; however, the transcription factor(s) that regulate HY5 transcription in response to UV-B and the impact of UV-B on the association of HY5 with its target promoters are currently unclear. Here, we show that HY5 binding to the promoters of UV-B-responsive genes is enhanced by UV-B in a UVR8-dependent manner in Arabidopsis thaliana. In agreement, overexpression of REPRESSOR OF UV-B PHOTOMORPHOGENESIS2, a negative regulator of UVR8 function, blocks UV-B-responsive HY5 enrichment at target promoters. Moreover, we have identified a T/G-box in the HY5 promoter that is required for its UV-B responsiveness. We show that HY5 and its homolog HYH bind to the T/G(HY5)-box cis-acting element and that they act redundantly in the induction of HY5 expression upon UV-B exposure. Therefore, HY5 is enriched at target promoters in response to UV-B in a UVR8 photoreceptor-dependent manner, and HY5 and HYH interact directly with a T/G-box cis-acting element of the HY5 promoter, mediating the transcriptional activation of HY5 in response to UV-B.
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Affiliation(s)
- Melanie Binkert
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
| | - László Kozma-Bognár
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6726 Szeged, Hungary
| | - Kata Terecskei
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6726 Szeged, Hungary
| | - Lieven De Veylder
- Department of Plant Systems Biology, VIB, B-9052 Ghent, Belgium Department of Plant Biotechnology and Bioinformatics, Ghent University, B-9052 Ghent, Belgium
| | - Ferenc Nagy
- Institute of Plant Biology, Biological Research Centre of the Hungarian Academy of Sciences, H-6726 Szeged, Hungary School of Biological Sciences, University of Edinburgh, EH9 3JR Edinburgh, United Kingdom
| | - Roman Ulm
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
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28
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Takeda J, Nakata R, Ueno H, Murakami A, Iseki M, Watanabe M. Possible involvement of a tetrahydrobiopterin in photoreception for UV-B-induced anthocyanin synthesis in carrot. Photochem Photobiol 2014; 90:1043-9. [PMID: 24943195 DOI: 10.1111/php.12302] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 06/14/2014] [Indexed: 01/19/2023]
Abstract
Our previous studies of action spectra for UV-B-induced anthocyanin accumulation in cultured carrot cells indicated that a reduced form of pterin, possibly tetrahydrobiopterin, contributes to UV-B photoreception. In this report, we provide additional evidence for the involvement of pterin in UV-B light sensing. UV-B-induced phenylalanine ammonia-lyase (PAL) activity was considerably suppressed by N-acetylserotonin (an inhibitor of tetrahydrobiopterin biosynthesis), and this suppression was partially recovered by adding biopterin or tetrahydrobiobiopterin. In addition, protein(s) specifically bound to biopterin were detected by radiolabeling experiments in N-acetylserotonin-treated cells. Furthermore, diphenyleneiodonium, a potent inhibitor of electron transfer, completely suppressed UV-B-induced PAL activity. These results suggest the occurrence of an unidentified UV-B photoreceptor (other than UVR8, the tryptophan-based UV-B sensor originally identified in Arabidopsis) with reduced pterin in carrot cells. After reexamining published action spectra, we suggest that anthocyanin synthesis is coordinately regulated by these two UV-B sensors.
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Affiliation(s)
- Junko Takeda
- Laboratory of Applied Microbiology and Biochemistry, Nara Women's University, Nara, Japan
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29
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Li X, Chung LW, Morokuma K, Li G. Theoretical Study on the UVR8 Photoreceptor: Sensing Ultraviolet-B by Tryptophan and Dissociation of Homodimer. J Chem Theory Comput 2014; 10:3319-30. [DOI: 10.1021/ct5003362] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Xin Li
- State
Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Dalian 116023, China
| | - Lung Wa Chung
- Fukui
Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
- Department
of Chemistry, South University of Science and Technology of China, Shenzhen 518055, China
| | - Keiji Morokuma
- Fukui
Institute for Fundamental Chemistry, Kyoto University, Kyoto 606-8103, Japan
| | - Guohui Li
- State
Key Lab of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Dalian 116023, China
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30
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On the mechanism of photoinduced dimer dissociation in the plant UVR8 photoreceptor. Proc Natl Acad Sci U S A 2014; 111:5219-24. [PMID: 24639509 DOI: 10.1073/pnas.1402025111] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
UV-B absorption by the photoreceptor UV resistance locus 8 (UVR8) consisting of two identical protein units triggers a signal chain used by plants in connection with protection and repair of UV-B induced damage. X-ray structural analysis of the purified protein [Christie JM, et al. (2012) Science 335(6075):1492-1496] [Wu D, et al. (2012) Nature 484(7393): 214-220] has revealed that the dimer is held together by arginine-aspartate salt bridges. In this paper we address the initial processes in the signal chain. On the basis of high-level quantum-chemical calculations, we propose a mechanism for the photodissociation of UVR8 that consists of three steps: (i) In each monomer, multiple tryptophans form an extended light-harvesting system in which the La excited state of Trp233 experiences strong electrostatic stabilization by the protein environment. The strong stabilization singles out this tryptophan to be an efficient exciton acceptor that accumulates the excitation energy from the entire protein subunit. (ii) A fast decay of the locally excited state by charge separation generates the radical ion pair Trp285(+)-Trp233(-) with a dipole moment of ∼18 D. (iii) Key to the proposed mechanism is that this large dipole moment drives the breaking of the salt bridges between the two monomer subunits. The suggested mechanism for the UV-B-driven dissociation of the dimer that rests on the prominent players Trp233 and Trp285 explains the experimental results obtained from mutagenesis of UVR8.
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31
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Wu M, Strid Å, Eriksson LA. Photochemical reaction mechanism of UV-B-induced monomerization of UVR8 dimers as the first signaling event in UV-B-regulated gene expression in plants. J Phys Chem B 2014; 118:951-65. [PMID: 24410443 DOI: 10.1021/jp4104118] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) protein has been identified to specifically mediate photomorphogenic UV-B responses by acting as a UV-B photoreceptor. The dimeric structure of the UVR8 protein dissociates into signaling-active monomers upon UV-B exposure, and the monomers rapidly interact with downstream signaling components to regulate gene expression. UVR8 monomers revert to dimers in the absence of UV-B radiation, thereby reversing transcription activation. UVR8 amino acid residues W233 and W285 have been identified to play critical roles in the UVR8 dimer for the response to UV-B irradiation. In the present work, the photoreaction mechanism for UVR8 monomerization is explored with quantum chemical cluster calculations and evaluated by molecular dynamics simulations using the wild-type UVR8 dimer and novel force field parameters developed for intermediate radicals formed in the photochemical process. Three different models are investigated, which show that the preferred mechanism for UVR8 monomerization involves electron transfer from residue W233 to W285 and onward to R338 initiated by UV-B irradiation, coupled to simultaneous proton transfer from W233 to D129 leading to the formation of protonated D129, a deprotonated W233 radical, and a neutral R338 radical. Due to the formation of the neutral R338 radical, salt bridges involving this residue are disrupted together with the concomitant interruption of several other key salt bridges R286-D96, R286-D107, R338-D44, R354-E43, and R354-E53. The resulting large decrease in protein-protein interaction energy arising from this sequence of events leads to the monomerization of the UVR8 dimer. The mechanism presented is in accord with all experimental data available to date.
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Affiliation(s)
- Min Wu
- Department of Chemistry and Molecular Biology, University of Gothenburg , SE-412 96 Göteborg, Sweden
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32
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Shi MZ, Xie DY. Biosynthesis and metabolic engineering of anthocyanins in Arabidopsis thaliana. Recent Pat Biotechnol 2014; 8:47-60. [PMID: 24354533 PMCID: PMC4036305 DOI: 10.2174/1872208307666131218123538] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 10/24/2012] [Accepted: 11/06/2012] [Indexed: 11/22/2022]
Abstract
Arabidopsis thaliana is the first model plant, the genome of which has been sequenced. In general, intensive studies on this model plant over the past nearly 30 years have led to many new revolutionary understandings in every single aspect of plant biology. Here, we review the current understanding of anthocyanin biosynthesis in this model plant. Although the investigation of anthocyanin structures in this model plant was not performed until 2002, numerous studies over the past three decades have been conducted to understand the biosynthesis of anthocyanins. To date, it appears that all pathway genes of anthocyanins have been molecularly, genetically and biochemically characterized in this plant. These fundamental accomplishments have made Arabidopsis an ideal model to understand the regulatory mechanisms of anthocyanin pathway. Several studies have revealed that the biosynthesis of anthocyanins is controlled by WD40-bHLH-MYB (WBM) transcription factor complexes under lighting conditions. However, how different regulatory complexes coordinately and specifically regulate the pathway genes of anthocyanins remains unclear. In this review, we discuss current progresses and findings including structural diversity, regulatory properties and metabolic engineering of anthocyanins in Arabidopsis thaliana.
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Affiliation(s)
| | - De-Yu Xie
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA.
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33
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Ultraviolet-B-mediated induction of protein-protein interactions in mammalian cells. Nat Commun 2013; 4:1779. [PMID: 23653191 DOI: 10.1038/ncomms2800] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/26/2013] [Indexed: 11/08/2022] Open
Abstract
Light-sensitive proteins are useful tools to control protein localization, activation and gene expression, but are currently limited to excitation with red or blue light. Here we report a novel optogenetic system based on the ultraviolet-B-dependent interaction of the Arabidopsis ultraviolet-B photoreceptor UVR8 with COP1 that can be performed in visible light background. We use this system to induce nuclear accumulation of cytoplasmic green fluorescent protein fused to UVR8 in cells expressing nuclear COP1, and to recruit a nucleoplasmic red fluorescent protein fused to COP1 to chromatin in cells expressing UVR8-H2B. We also show that ultraviolet-B-dependent interactions between DNA-binding and transcription activation domains result in a linear induction of gene expression. The UVR8-COP1 interactions in mammalian cells can be induced using subsecond pulses of ultraviolet-B light and last several hours. As UVR8 photoperception is based on intrinsic tryptophan residues, these interactions do not depend on the addition of an exogenous chromophore.
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34
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Wu M, Strid Å, Eriksson LA. Interactions and Stabilities of the UV RESISTANCE LOCUS8 (UVR8) Protein Dimer and Its Key Mutants. J Chem Inf Model 2013; 53:1736-46. [DOI: 10.1021/ci4001822] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Min Wu
- Department of Chemistry and
Molecular Biology, University of Gothenburg, SE-412 96 Göteborg,
Sweden
| | - Åke Strid
- School of Science
and Technology,
Örebro University, SE-70182 Örebro, Sweden
| | - Leif A. Eriksson
- Department of Chemistry and
Molecular Biology, University of Gothenburg, SE-412 96 Göteborg,
Sweden
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35
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Tilbrook K, Arongaus AB, Binkert M, Heijde M, Yin R, Ulm R. The UVR8 UV-B Photoreceptor: Perception, Signaling and Response. THE ARABIDOPSIS BOOK 2013; 11:e0164. [PMID: 23864838 PMCID: PMC3711356 DOI: 10.1199/tab.0164] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Ultraviolet-B radiation (UV-B) is an intrinsic part of sunlight that is accompanied by significant biological effects. Plants are able to perceive UV-B using the UV-B photoreceptor UVR8 which is linked to a specific molecular signaling pathway and leads to UV-B acclimation. Herein we review the biological process in plants from initial UV-B perception and signal transduction through to the known UV-B responses that promote survival in sunlight. The UVR8 UV-B photoreceptor exists as a homodimer that instantly monomerises upon UV-B absorption via specific intrinsic tryptophans which act as UV-B chromophores. The UVR8 monomer interacts with COP1, an E3 ubiquitin ligase, initiating a molecular signaling pathway that leads to gene expression changes. This signaling output leads to UVR8-dependent responses including UV-B-induced photomorphogenesis and the accumulation of UV-B-absorbing flavonols. Negative feedback regulation of the pathway is provided by the WD40-repeat proteins RUP1 and RUP2, which facilitate UVR8 redimerization, disrupting the UVR8-COP1 interaction. Despite rapid advancements in the field of recent years, further components of UVR8 UV-B signaling are constantly emerging, and the precise interplay of these and the established players UVR8, COP1, RUP1, RUP2 and HY5 needs to be defined. UVR8 UV-B signaling represents our further understanding of how plants are able to sense their light environment and adjust their growth accordingly.
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Affiliation(s)
- Kimberley Tilbrook
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
| | - Adriana B. Arongaus
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
| | - Melanie Binkert
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
| | - Marc Heijde
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
| | - Ruohe Yin
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
| | - Roman Ulm
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
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36
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Morales LO, Brosché M, Vainonen J, Jenkins GI, Wargent JJ, Sipari N, Strid Å, Lindfors AV, Tegelberg R, Aphalo PJ. Multiple roles for UV RESISTANCE LOCUS8 in regulating gene expression and metabolite accumulation in Arabidopsis under solar ultraviolet radiation. PLANT PHYSIOLOGY 2013; 161:744-59. [PMID: 23250626 PMCID: PMC3561016 DOI: 10.1104/pp.112.211375] [Citation(s) in RCA: 127] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Accepted: 12/17/2012] [Indexed: 05/18/2023]
Abstract
Photomorphogenic responses triggered by low fluence rates of ultraviolet B radiation (UV-B; 280-315 nm) are mediated by the UV-B photoreceptor UV RESISTANCE LOCUS8 (UVR8). Beyond our understanding of the molecular mechanisms of UV-B perception by UVR8, there is still limited information on how the UVR8 pathway functions under natural sunlight. Here, wild-type Arabidopsis (Arabidopsis thaliana) and the uvr8-2 mutant were used in an experiment outdoors where UV-A (315-400 nm) and UV-B irradiances were attenuated using plastic films. Gene expression, PYRIDOXINE BIOSYNTHESIS1 (PDX1) accumulation, and leaf metabolite signatures were analyzed. The results show that UVR8 is required for transcript accumulation of genes involved in UV protection, oxidative stress, hormone signal transduction, and defense against herbivores under solar UV. Under natural UV-A irradiance, UVR8 is likely to interact with UV-A/blue light signaling pathways to moderate UV-B-driven transcript and PDX1 accumulation. UVR8 both positively and negatively affects UV-A-regulated gene expression and metabolite accumulation but is required for the UV-B induction of phenolics. Moreover, UVR8-dependent UV-B acclimation during the early stages of plant development may enhance normal growth under long-term exposure to solar UV.
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Affiliation(s)
- Luis O Morales
- Division of Plant Biology, Department of Biosciences, University of Helsinki, FI-00014 Helsinki, Finland.
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37
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Davey MP, Susanti NI, Wargent JJ, Findlay JE, Paul Quick W, Paul ND, Jenkins GI. The UV-B photoreceptor UVR8 promotes photosynthetic efficiency in Arabidopsis thaliana exposed to elevated levels of UV-B. PHOTOSYNTHESIS RESEARCH 2012; 114:121-31. [PMID: 23161229 DOI: 10.1007/s11120-012-9785-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 10/31/2012] [Indexed: 05/05/2023]
Abstract
The UV-B photoreceptor UVR8 regulates expression of genes in response to UV-B, some encoding chloroplast proteins, but the importance of UVR8 in maintaining photosynthetic competence is unknown. The maximum quantum yield of PSII (F (v)/F(m)) and the operating efficiency of PSII (Φ(PSII)) were measured in wild-type and uvr8 mutant Arabidopsis thaliana. The importance of specific UVR8-regulated genes in maintaining photosynthetic competence was examined using mutants. Both F (v)/F(m) and Φ(PSII) decreased when plants were exposed to elevated UV-B, in general more so in uvr8 mutant plants than wild-type. UV-B increased the level of psbD-BLRP (blue light responsive promoter) transcripts, encoding the PSII D2 protein. This increase was mediated by the UVR8-regulated chloroplast RNA polymerase sigma factor SIG5, but SIG5 was not required to maintain photosynthetic efficiency at elevated UV-B. Levels of the D1 protein of PSII decreased markedly when plants were exposed to elevated UV-B, but there was no significant difference between wild-type and uvr8 under conditions where the mutant showed increased photoinhibition. The results show that UVR8 promotes photosynthetic efficiency at elevated levels of UV-B. Loss of the DI polypeptide is probably important in causing photoinhibition, but does not entirely explain the reduced photosynthetic efficiency of the uvr8 mutant compared to wild-type.
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Affiliation(s)
- Matthew P Davey
- Department of Animal and Plant Sciences, University of Sheffield, Alfred Denny Building, Western Bank, Sheffield S10 2TN, UK
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38
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O’Hara A, Jenkins GI. In vivo function of tryptophans in the Arabidopsis UV-B photoreceptor UVR8. THE PLANT CELL 2012; 24:3755-66. [PMID: 23012433 PMCID: PMC3480300 DOI: 10.1105/tpc.112.101451] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 08/10/2012] [Accepted: 08/23/2012] [Indexed: 05/19/2023]
Abstract
Arabidopsis thaliana UV RESISTANCE LOCUS8 (UVR8) is a photoreceptor specifically for UV-B light that initiates photomorphogenic responses in plants. UV-B exposure causes rapid conversion of UVR8 from dimer to monomer, accumulation in the nucleus, and interaction with CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1), which functions with UVR8 in UV-B responses. Studies in yeast and with purified UVR8 implicate several tryptophan amino acids in UV-B photoreception. However, their roles in UV-B responses in plants, and the functional significance of all 14 UVR8 tryptophans, are not known. Here we report the functions of the UVR8 tryptophans in vivo. Three tryptophans in the β-propeller core are important in maintaining structural stability and function of UVR8. However, mutation of three other core tryptophans and four at the dimeric interface has no apparent effect on function in vivo. Mutation of three tryptophans implicated in UV-B photoreception, W233, W285, and W337, impairs photomorphogenic responses to different extents. W285 is essential for UVR8 function in plants, whereas W233 is important but not essential for function, and W337 has a lesser role. Ala mutants of these tryptophans appear monomeric and constitutively bind COP1 in plants, but their responses indicate that monomer formation and COP1 binding are not sufficient for UVR8 function.
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39
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Jiang L, Wang Y, Olof Björn L, He JX, Li S. Sensing of UV-B radiation by plants. PLANT SIGNALING & BEHAVIOR 2012; 7:999-1003. [PMID: 22751358 PMCID: PMC3474703 DOI: 10.4161/psb.20815] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Daylight UV-B (UV-B) radiation (280-315 nm) is, because of its photochemical effects and potential destructive impact, an important environmental factor for plants. After decades of fruitless attempts, a receptor molecule, UVR8, for sensing of ambient UV-B radiation by plants has been characterized, and the initial steps in signal transduction have been identified. There are, however, other signaling pathways, and there are apparent contradictions in the literature. There is still much to find out about the complex signaling network in plants for processing of information about the daylight surrounding them.
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Affiliation(s)
- Lei Jiang
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education; School of Life Science; South China Normal University; Guangzhou, China
- State Key Laboratory of Agrobiotechnology and School of Life Sciences; The Chinese University of Hong Kong; Hong Kong, China
| | - Yan Wang
- College of Life Science and Technology; Jinan University; Guangzhou, China
| | - Lars Olof Björn
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education; School of Life Science; South China Normal University; Guangzhou, China
- Department of Biology; Lund University; Lund, Sweden
| | - Jun-Xian He
- State Key Laboratory of Agrobiotechnology and School of Life Sciences; The Chinese University of Hong Kong; Hong Kong, China
| | - Shaoshan Li
- Key Laboratory of Ecology and Environmental Science in Guangdong Higher Education; School of Life Science; South China Normal University; Guangzhou, China
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40
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Lang-Mladek C, Xie L, Nigam N, Chumak N, Binkert M, Neubert S, Hauser MT. UV-B signaling pathways and fluence rate dependent transcriptional regulation of ARIADNE12. PHYSIOLOGIA PLANTARUM 2012; 145:527-39. [PMID: 22188380 DOI: 10.1111/j.1399-3054.2011.01561.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
ARI12 belongs to a family of 'RING between RING fingers' (RBR) domain proteins with E3 ligase activity (Eisenhaber et al. 2007). The Arabidopsis genome codes for 14 ARI genes and two pseudogenes (Mladek et al. 2003). Under standard growth conditions ARI12 is predominantly expressed in roots. In addition, ARI12 is strongly induced in leaves following exposure to ultraviolet (UV)-B radiation at dosages similar to those in areas under a reduced ozone layer. With quantitative reverse transcription polymerase chain reaction analyses and promoter:reporter constructs we show that the expression of ARI12 peaks 2-4 h after UV-B radiation exposure. To test if ARI12's transcriptional activation depends on key players of the UV-B signaling pathway, ARI12 expression was quantified in mutants of the ELONGATED HYPOCOTYL5 (HY5), HY5 HOMOLOG (HYH) and the UV RESISTANCE LOCUS8 (UVR8) genes. ARI12 transcription was reduced by 50-70% in hy5, hyh and hy5/hyh double mutants, but not in uvr8 mutants. However, under low fluence rate UV-B conditions ARI12 is not induced in these mutants. Our results show that ARI12 represents a downstream target of the low fluence rate UVR8/HY5/HYH UV-B signaling pathway while under high fluence rates its expression is regulated by the two bZIP transcription factors HY5 and HYH in an UVR8-independent manner.
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Affiliation(s)
- Christina Lang-Mladek
- Department of Applied Genetics and Cell Biology, BOKU-University of Natural Resources and Life Sciences, Muthgasse 18, 1190 Vienna, Austria
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41
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Heijde M, Ulm R. UV-B photoreceptor-mediated signalling in plants. TRENDS IN PLANT SCIENCE 2012; 17:230-7. [PMID: 22326562 DOI: 10.1016/j.tplants.2012.01.007] [Citation(s) in RCA: 242] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2011] [Revised: 01/12/2012] [Accepted: 01/16/2012] [Indexed: 05/05/2023]
Abstract
Ultraviolet-B radiation (UV-B) is a key environmental signal that is specifically perceived by plants to promote UV acclimation and survival in sunlight. Whereas the plant photoreceptors for visible light are rather well characterised, the UV-B photoreceptor UVR8 was only recently described at the molecular level. Here, we review the current understanding of the UVR8 photoreceptor-mediated pathway in the context of UV-B perception mechanism, early signalling components and physiological responses. We further outline the commonalities in UV-B and visible light signalling as well as highlight differences between these pathways.
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Affiliation(s)
- Marc Heijde
- Department of Botany and Plant Biology, University of Geneva, Sciences III, CH-1211 Geneva 4, Switzerland
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42
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Christie JM, Arvai AS, Baxter KJ, Heilmann M, Pratt AJ, O'Hara A, Kelly SM, Hothorn M, Smith BO, Hitomi K, Jenkins GI, Getzoff ED. Plant UVR8 photoreceptor senses UV-B by tryptophan-mediated disruption of cross-dimer salt bridges. Science 2012; 335:1492-6. [PMID: 22323738 DOI: 10.1126/science.1218091] [Citation(s) in RCA: 314] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The recently identified plant photoreceptor UVR8 (UV RESISTANCE LOCUS 8) triggers regulatory changes in gene expression in response to ultraviolet-B (UV-B) light through an unknown mechanism. Here, crystallographic and solution structures of the UVR8 homodimer, together with mutagenesis and far-UV circular dichroism spectroscopy, reveal its mechanisms for UV-B perception and signal transduction. β-propeller subunits form a remarkable, tryptophan-dominated, dimer interface stitched together by a complex salt-bridge network. Salt-bridging arginines flank the excitonically coupled cross-dimer tryptophan "pyramid" responsible for UV-B sensing. Photoreception reversibly disrupts salt bridges, triggering dimer dissociation and signal initiation. Mutation of a single tryptophan to phenylalanine retunes the photoreceptor to detect UV-C wavelengths. Our analyses establish how UVR8 functions as a photoreceptor without a prosthetic chromophore to promote plant development and survival in sunlight.
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Affiliation(s)
- John M Christie
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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Van Buskirk EK, Decker PV, Chen M. Photobodies in light signaling. PLANT PHYSIOLOGY 2012; 158:52-60. [PMID: 21951469 PMCID: PMC3252093 DOI: 10.1104/pp.111.186411] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2011] [Accepted: 09/22/2011] [Indexed: 05/17/2023]
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Tohge T, Kusano M, Fukushima A, Saito K, Fernie AR. Transcriptional and metabolic programs following exposure of plants to UV-B irradiation. PLANT SIGNALING & BEHAVIOR 2011; 6:1987-92. [PMID: 22112450 PMCID: PMC3337192 DOI: 10.4161/psb.6.12.18240] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In order to adapt to environmental changes of light species and intensity, higher plants furnish complicate signaling systems such as the UVR/COP/HY5 cascade which links several diverse classes of photoreceptors. In addition UV-B light provokes accelerated production of UV-B protectants such as flavonoids and vitamins. Following intensive research efforts, genes in the UV-B signaling cascade have been characterized via forward genetics approaches following mutant screens relying on sensitivity to UV-B irradiation. However detailed processes of the linkage between light signaling and the upregulation of metabolite accumulation remain unclear. Here we review both the light signal cascades and metabolite pathways responding to UV-B exposure. Finally we generate co-expression network analysis using published data in order to find novel candidate genes which link light signaling and transcriptional regulation to metabolic biosynthesis in attempt to describe how these processes are interlinked.
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Affiliation(s)
- Takayuki Tohge
- RIKEN Plant Science Center; Yokohama, Japan
- Max-Planck Institute for Molecular Plant Physiology; Potsdam-Golm, Germany
- Correspondence to: Takayuki Tohge, or Alisdair R. Fernie,
| | | | | | - Kazuki Saito
- RIKEN Plant Science Center; Yokohama, Japan
- Graduate School of Pharmaceutical Sciences; Chiba University; Chiba, Japan
| | - Alisdair R. Fernie
- Max-Planck Institute for Molecular Plant Physiology; Potsdam-Golm, Germany
- Correspondence to: Takayuki Tohge, or Alisdair R. Fernie,
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Casati P, Campi M, Morrow DJ, Fernandes JF, Walbot V. Transcriptomic, proteomic and metabolomic analysis of UV-B signaling in maize. BMC Genomics 2011; 12:321. [PMID: 21679461 PMCID: PMC3141669 DOI: 10.1186/1471-2164-12-321] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Accepted: 06/16/2011] [Indexed: 12/19/2022] Open
Abstract
Background Under normal solar fluence, UV-B damages macromolecules, but it also elicits physiological acclimation and developmental changes in plants. Excess UV-B decreases crop yield. Using a treatment twice solar fluence, we focus on discovering signals produced in UV-B-irradiated maize leaves that translate to systemic changes in shielded leaves and immature ears. Results Using transcriptome and proteomic profiling, we tracked the kinetics of transcript and protein alterations in exposed and shielded organs over 6 h. In parallel, metabolic profiling identified candidate signaling molecules based on rapid increase in irradiated leaves and increased levels in shielded organs; pathways associated with the synthesis, sequestration, or degradation of some of these potential signal molecules were UV-B-responsive. Exposure of just the top leaf substantially alters the transcriptomes of both irradiated and shielded organs, with greater changes as additional leaves are irradiated. Some phenylpropanoid pathway genes are expressed only in irradiated leaves, reflected in accumulation of pathway sunscreen molecules. Most protein changes detected occur quickly: approximately 92% of the proteins in leaves and 73% in immature ears changed after 4 h UV-B were altered by a 1 h UV-B treatment. Conclusions There were significant transcriptome, proteomic, and metabolomic changes under all conditions studied in both shielded and irradiated organs. A dramatic decrease in transcript diversity in irradiated and shielded leaves occurs between 0 h and 1 h, demonstrating the susceptibility of plants to short term UV-B spikes as during ozone depletion. Immature maize ears are highly responsive to canopy leaf exposure to UV-B.
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Affiliation(s)
- Paula Casati
- Centro de Estudios Fotosintéticos y Bioquímicos, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina
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Wu M, Grahn E, Eriksson LA, Strid A. Computational evidence for the role of Arabidopsis thaliana UVR8 as UV-B photoreceptor and identification of its chromophore amino acids. J Chem Inf Model 2011; 51:1287-95. [PMID: 21561100 DOI: 10.1021/ci200017f] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A homology model of the Arabidopsis thaliana UV resistance locus 8 (UVR8) protein is presented herein, showing a seven-bladed β-propeller conformation similar to the globular structure of RCC1. The UVR8 amino acid sequence contains a very high amount of conserved tryptophans, and the homology model shows that seven of these tryptophans cluster at the 'top surface' of the UVR8 protein where they are intermixed with positive residues (mainly arginines) and a couple of tyrosines. Quantum chemical calculations of excitation spectra of both a large cluster model involving all twelve above-mentioned residues and smaller fragments thereof reveal that absorption maxima appearing in the 280-300 nm range for the full cluster result from interactions between the central tryptophans and surrounding arginines. This observation coincides with the published experimentally measured action spectrum for the UVR8-dependent UV-B stimulation of HY5 transcription in mature A. thaliana leaf tissue. In total these findings suggest that UVR8 has in fact in itself the ability to be an ultraviolet-B photoreceptor in plants.
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Affiliation(s)
- Min Wu
- School of Chemistry, National University of Ireland-Galway, Galway, Ireland
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Rizzini L, Favory JJ, Cloix C, Faggionato D, O'Hara A, Kaiserli E, Baumeister R, Schäfer E, Nagy F, Jenkins GI, Ulm R. Perception of UV-B by the Arabidopsis UVR8 protein. Science 2011; 332:103-6. [PMID: 21454788 DOI: 10.1126/science.1200660] [Citation(s) in RCA: 691] [Impact Index Per Article: 53.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
To optimize their growth and survival, plants perceive and respond to ultraviolet-B (UV-B) radiation. However, neither the molecular identity of the UV-B photoreceptor nor the photoperception mechanism is known. Here we show that dimers of the UVR8 protein perceive UV-B, probably by a tryptophan-based mechanism. Absorption of UV-B induces instant monomerization of the photoreceptor and interaction with COP1, the central regulator of light signaling. Thereby this signaling cascade controlled by UVR8 mediates UV-B photomorphogenic responses securing plant acclimation and thus promotes survival in sunlight.
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Affiliation(s)
- Luca Rizzini
- Faculty of Biology, Institute of Biology II, University of Freiburg, D-79104 Freiburg, Germany
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Ballaré CL, Caldwell MM, Flint SD, Robinson SA, Bornman JF. Effects of solar ultraviolet radiation on terrestrial ecosystems. Patterns, mechanisms, and interactions with climate change. Photochem Photobiol Sci 2011; 10:226-41. [DOI: 10.1039/c0pp90035d] [Citation(s) in RCA: 277] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Falcone Ferreyra ML, Rius S, Emiliani J, Pourcel L, Feller A, Morohashi K, Casati P, Grotewold E. Cloning and characterization of a UV-B-inducible maize flavonol synthase. THE PLANT JOURNAL 2010; 62:77-91. [PMID: 20059741 DOI: 10.1111/j.1365-313x.2010.04133.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
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Mazza CA, Izaguirre MM, Curiale J, Ballaré CL. A look into the invisible: ultraviolet-B sensitivity in an insect (Caliothrips phaseoli) revealed through a behavioural action spectrum. Proc Biol Sci 2009; 277:367-73. [PMID: 19846453 DOI: 10.1098/rspb.2009.1565] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Caliothrips phaseoli, a phytophagous insect, detects and responds to solar ultraviolet-B radiation (UV-B; lambda <or= 315 nm) under field conditions. A highly specific mechanism must be present in the thrips visual system in order to detect this narrow band of solar radiation, which is at least 30 times less abundant than the UV-A (315-400 nm), to which many insects are sensitive. We constructed an action spectrum of thrips responses to light by studying their behavioural reactions to monochromatic irradiation under confinement conditions. Thrips were maximally sensitive to wavelengths between 290 and 330 nm; human-visible wavelengths (lambda >or= 400 nm) failed to elicit any response. All but six ommatidia of the thrips compound eye were highly fluorescent when exposed to UV-A of wavelengths longer than 330 nm. We hypothesized that the fluorescent compound acts as an internal filter, preventing radiation with lambda > 330 nm from reaching the photoreceptor cells. Calculations based on the putative filter transmittance and a visual pigment template of lambda(max) = 360 nm produced a sensitivity spectrum that was strikingly similar to the action spectrum of UV-induced behavioural response. These results suggest that specific UV-B vision in thrips is achieved by a standard UV-A photoreceptor and a sharp cut-off internal filter that blocks longer UV wavelengths in the majority of the ommatidia.
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Affiliation(s)
- Carlos A Mazza
- Ifeva, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires, , Avenida San Martín 4453, C1417DSE Buenos Aires, Argentina.
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