101
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Benson CL, Kepka M, Wunschel C, Rajagopalan N, Nelson KM, Christmann A, Abrams SR, Grill E, Loewen MC. Abscisic acid analogs as chemical probes for dissection of abscisic acid responses in Arabidopsis thaliana. PHYTOCHEMISTRY 2015; 113:96-107. [PMID: 24726371 DOI: 10.1016/j.phytochem.2014.03.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2013] [Revised: 03/06/2014] [Accepted: 03/13/2014] [Indexed: 05/08/2023]
Abstract
Abscisic acid (ABA) is a phytohormone known to mediate numerous plant developmental processes and responses to environmental stress. In Arabidopsis thaliana, ABA acts, through a genetically redundant family of ABA receptors entitled Regulatory Component of ABA Receptor (RCAR)/Pyrabactin Resistant 1 (PYR1)/Pyrabactin Resistant-Like (PYL) receptors comprised of thirteen homologues acting in concert with a seven-member set of phosphatases. The individual contributions of A. thaliana RCARs and their binding partners with respect to specific physiological functions are as yet poorly understood. Towards developing efficacious plant growth regulators selective for specific ABA functions and tools for elucidating ABA perception, a panel of ABA analogs altered specifically on positions around the ABA ring was assembled. These analogs have been used to probe thirteen RCARs and four type 2C protein phosphatases (PP2Cs) and were also screened against representative physiological assays in the model plant Arabidopsis. The 1'-O methyl ether of (S)-ABA was identified as selective in that, at physiologically relevant levels, it regulates stomatal aperture and improves drought tolerance, but does not inhibit germination or root growth. Analogs with the 7'- and 8'-methyl groups of the ABA ring replaced with bulkier groups generally retained the activity and stereoselectivity of (S)- and (R)-ABA, while alteration of the 9'-methyl group afforded an analog that substituted for ABA in inhibiting germination but neither root growth nor stomatal closure. Further in vitro testing indicated differences in binding of analogs to individual RCARs, as well as differences in the enzyme activity resulting from specific PP2Cs bound to RCAR-analog complexes. Ultimately, these findings highlight the potential of a broader chemical genetics approach for dissection of the complex network mediating ABA-perception, signaling and functionality within a given species and modifications in the future design of ABA agonists.
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Affiliation(s)
- Chantel L Benson
- National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada
| | - Michal Kepka
- Lehrstuhl für Botanik, Technische Universität München, D-85354 Freising, Germany
| | - Christian Wunschel
- Lehrstuhl für Botanik, Technische Universität München, D-85354 Freising, Germany
| | | | - Ken M Nelson
- National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada
| | - Alexander Christmann
- Lehrstuhl für Botanik, Technische Universität München, D-85354 Freising, Germany
| | - Suzanne R Abrams
- Department of Chemistry, University of Saskatchewan, Saskatoon, SK, Canada.
| | - Erwin Grill
- Lehrstuhl für Botanik, Technische Universität München, D-85354 Freising, Germany
| | - Michele C Loewen
- National Research Council of Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada; Department of Biochemistry, University of Saskatchewan, Saskatoon, SK, Canada
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102
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Zhang HM, Wheeler S, Xia X, Radchuk R, Weber H, Offler CE, Patrick JW. Differential transcriptional networks associated with key phases of ingrowth wall construction in trans-differentiating epidermal transfer cells of Vicia faba cotyledons. BMC PLANT BIOLOGY 2015; 15:103. [PMID: 25887034 PMCID: PMC4437447 DOI: 10.1186/s12870-015-0486-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 04/01/2015] [Indexed: 05/08/2023]
Abstract
BACKGROUND Transfer cells are characterized by intricate ingrowth walls, comprising an uniform wall upon which wall ingrowths are deposited. The ingrowth wall forms a scaffold to support an amplified plasma membrane surface area enriched in membrane transporters that collectively confers transfer cells with an enhanced capacity for membrane transport at bottlenecks for apo-/symplasmic exchange of nutrients. However, the underlying molecular mechanisms regulating polarized construction of the ingrowth wall and membrane transporter profile are poorly understood. RESULTS An RNAseq study of an inducible epidermal transfer cell system in cultured Vicia faba cotyledons identified transfer cell specific transcriptomes associated with uniform wall and wall ingrowth deposition. All functional groups of genes examined were expressed before and following transition to a transfer cell fate. What changed were the isoform profiles of expressed genes within functional groups. Genes encoding ethylene and Ca(2+) signal generation and transduction pathways were enriched during uniform wall construction. Auxin-and reactive oxygen species-related genes dominated during wall ingrowth formation and ABA genes were evenly expressed across ingrowth wall construction. Expression of genes encoding kinesins, formins and villins was consistent with reorganization of cytoskeletal components. Uniform wall and wall ingrowth specific expression of exocyst complex components and SNAREs suggested specific patterns of exocytosis while dynamin mediated endocytotic activity was consistent with establishing wall ingrowth loci. Key regulatory genes of biosynthetic pathways for sphingolipids and sterols were expressed across ingrowth wall construction. Transfer cell specific expression of cellulose synthases was absent. Rather xyloglucan, xylan and pectin biosynthetic genes were selectively expressed during uniform wall construction. More striking was expression of genes encoding enzymes for re-modelling/degradation of cellulose, xyloglucans, pectins and callose. Extensins dominated the cohort of expressed wall structural proteins and particularly so across wall ingrowth development. Ion transporters were selectively expressed throughout ingrowth wall development along with organic nitrogen transporters and a large group of ABC transporters. Sugar transporters were less represented. CONCLUSIONS Pathways regulating signalling and intracellular organization were fine tuned whilst cell wall construction and membrane transporter profiles were altered substantially upon transiting to a transfer cell fate. Each phase of ingrowth wall construction was linked with unique cohorts of expressed genes.
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Affiliation(s)
- Hui-Ming Zhang
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Simon Wheeler
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Xue Xia
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - Ruslana Radchuk
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466, Gatersleben, Germany.
| | - Hans Weber
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Corrensstrasse 3, D-06466, Gatersleben, Germany.
| | - Christina E Offler
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
| | - John W Patrick
- School of Environmental and Life Sciences, The University of Newcastle, Callaghan, NSW 2308, Australia.
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103
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Sechet J, Roux C, Plessis A, Effroy D, Frey A, Perreau F, Biniek C, Krieger-Liszkay A, Macherel D, North HM, Mireau H, Marion-Poll A. The ABA-deficiency suppressor locus HAS2 encodes the PPR protein LOI1/MEF11 involved in mitochondrial RNA editing. MOLECULAR PLANT 2015; 8:644-56. [PMID: 25708384 DOI: 10.1016/j.molp.2014.12.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/04/2014] [Accepted: 12/07/2014] [Indexed: 05/10/2023]
Abstract
The hot ABA-deficiency suppressor2 (has2) mutation increases drought tolerance and the ABA sensitivity of stomata closure and seed germination. Here we report that the HAS2 locus encodes the mitochondrial editing factor11 (MEF11), also known as lovastatin insensitive1. has2/mef11 mutants exhibited phenotypes very similar to the ABA-hypersensitive mutant, hai1-1 pp2ca-1 hab1-1 abi1-2, which is impaired in four genes encoding type 2C protein phosphatases (PP2C) that act as upstream negative regulators of the ABA signaling cascade. Like pp2c, mef11 plants were more resistant to progressive water stress and seed germination was more sensitive to paclobutrazol (a gibberellin biosynthesis inhibitor) as well as mannitol and NaCl, compared with the wild-type plants. Phenotypic alterations in mef11 were associated with the lack of editing of transcripts for the mitochondrial cytochrome c maturation FN2 (ccmFN2) gene, which encodes a cytochrome c-heme lyase subunit involved in cytochrome c biogenesis. Although the abundance of electron transfer chain complexes was not affected, their dysfunction could be deduced from increased respiration and altered production of hydrogen peroxide and nitric oxide in mef11 seeds. As minor defects in mitochondrial respiration affect ABA signaling, this suggests an essential role for ABA in mitochondrial retrograde regulation.
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Affiliation(s)
- Julien Sechet
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Camille Roux
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Anne Plessis
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Delphine Effroy
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Anne Frey
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - François Perreau
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Catherine Biniek
- CEA Saclay, IBiTec-S, CNRS UMR 8221, Serv Bioenerget Biol Struct & Mécanisme, F-91191 Gif Sur Yvette, France
| | - Anja Krieger-Liszkay
- CEA Saclay, IBiTec-S, CNRS UMR 8221, Serv Bioenerget Biol Struct & Mécanisme, F-91191 Gif Sur Yvette, France
| | - David Macherel
- Université d'Angers, UMR IRHS 1345, INRA, Agrocampus Ouest, F-49045 Angers, France
| | - Helen M North
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Hakim Mireau
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; Institut Jean-Pierre Bourgin, INRA, Bât 7, F-78026 Versailles Cedex, France.
| | - Annie Marion-Poll
- INRA, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; AgroParisTech, Institut Jean-Pierre Bourgin, UMR 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France; Institut Jean-Pierre Bourgin, INRA, Bât 2, F-78026 Versailles Cedex, France.
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104
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Mickelbart MV, Hasegawa PM, Bailey-Serres J. Genetic mechanisms of abiotic stress tolerance that translate to crop yield stability. Nat Rev Genet 2015; 16:237-51. [PMID: 25752530 DOI: 10.1038/nrg3901] [Citation(s) in RCA: 411] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Crop yield reduction as a consequence of increasingly severe climatic events threatens global food security. Genetic loci that ensure productivity in challenging environments exist within the germplasm of crops, their wild relatives and species that are adapted to extreme environments. Selective breeding for the combination of beneficial loci in germplasm has improved yields in diverse environments throughout the history of agriculture. An effective new paradigm is the targeted identification of specific genetic determinants of stress adaptation that have evolved in nature and their precise introgression into elite varieties. These loci are often associated with distinct regulation or function, duplication and/or neofunctionalization of genes that maintain plant homeostasis.
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Affiliation(s)
- Michael V Mickelbart
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Paul M Hasegawa
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, Indiana 47907, USA
| | - Julia Bailey-Serres
- 1] Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California Riverside, California 92521, USA. [2] Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands
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105
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Clauw P, Coppens F, De Beuf K, Dhondt S, Van Daele T, Maleux K, Storme V, Clement L, Gonzalez N, Inzé D. Leaf responses to mild drought stress in natural variants of Arabidopsis. PLANT PHYSIOLOGY 2015; 167:800-16. [PMID: 25604532 PMCID: PMC4348775 DOI: 10.1104/pp.114.254284] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/16/2015] [Indexed: 05/18/2023]
Abstract
Although the response of plants exposed to severe drought stress has been studied extensively, little is known about how plants adapt their growth under mild drought stress conditions. Here, we analyzed the leaf and rosette growth response of six Arabidopsis (Arabidopsis thaliana) accessions originating from different geographic regions when exposed to mild drought stress. The automated phenotyping platform WIWAM was used to impose stress early during leaf development, when the third leaf emerges from the shoot apical meristem. Analysis of growth-related phenotypes showed differences in leaf development between the accessions. In all six accessions, mild drought stress reduced both leaf pavement cell area and number without affecting the stomatal index. Genome-wide transcriptome analysis (using RNA sequencing) of early developing leaf tissue identified 354 genes differentially expressed under mild drought stress in the six accessions. Our results indicate the existence of a robust response over different genetic backgrounds to mild drought stress in developing leaves. The processes involved in the overall mild drought stress response comprised abscisic acid signaling, proline metabolism, and cell wall adjustments. In addition to these known severe drought-related responses, 87 genes were found to be specific for the response of young developing leaves to mild drought stress.
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Affiliation(s)
- Pieter Clauw
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Frederik Coppens
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Kristof De Beuf
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Stijn Dhondt
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Twiggy Van Daele
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Katrien Maleux
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Veronique Storme
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Lieven Clement
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Nathalie Gonzalez
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
| | - Dirk Inzé
- Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.);Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium (P.C., F.C., S.D., T.V.D., K.M., V.S., N.G., D.I.); andDepartment of Applied Mathematics Computer Science and Statistics (K.D.B., L.C.) and Stat-Gent CRESCENDO, Department of Applied Mathematics and Computer Science (K.D.B.), Ghent University, 9000 Ghent, Belgium
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106
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Agrochemical control of plant water use using engineered abscisic acid receptors. Nature 2015; 520:545-8. [DOI: 10.1038/nature14123] [Citation(s) in RCA: 178] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 11/28/2014] [Indexed: 12/13/2022]
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107
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Feng J, Zhao S, Chen X, Wang W, Dong W, Chen J, Shen JR, Liu L, Kuang T. Biochemical and structural study of Arabidopsis hexokinase 1. ACTA ACUST UNITED AC 2015; 71:367-75. [PMID: 25664748 DOI: 10.1107/s1399004714026091] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Accepted: 11/27/2014] [Indexed: 01/11/2023]
Abstract
Hexokinase 1 from Arabidopsis thaliana (AtHXK1) plays a dual role in glycolysis and sugar sensing for vital metabolic and physiological processes. The uncoupling of glucose signalling from glucose metabolism was demonstrated by the analysis of two mutants (AtHXK1(G104D) and AtHXK1(S177A)) that are catalytically inactive but still functional in signalling. In this study, substrate-binding experiments indicate that the two catalytically inactive mutants have a high affinity for glucose, and an ordered substrate-binding mechanism has been observed for wild-type AtHXK1. The structure of AtHXK1 was determined both in its inactive unliganded form and in its active glucose-bound form at resolutions of 1.8 and 2.0 Å, respectively. These structures reveal a domain rearrangement of AtHXK1 upon glucose binding. The 2.1 Å resolution structure of AtHXK1(S177A) in the glucose-bound form shows similar glucose-binding interactions as the wild type. A glucose-sensing network has been proposed based on these structures. Taken together, the results provide a structural explanation for the dual functions of AtHXK1.
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Affiliation(s)
- Juan Feng
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Shun Zhao
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Xuemin Chen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Wenda Wang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Wei Dong
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Jinghua Chen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Jian-Ren Shen
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Lin Liu
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
| | - Tingyun Kuang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, 20 Nanxincun, Haidian District, Beijing 100093, People's Republic of China
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108
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Magalhães AP, Verde N, Reis F, Martins I, Costa D, Lino-Neto T, Castro PH, Tavares RM, Azevedo H. RNA-Seq and Gene Network Analysis Uncover Activation of an ABA-Dependent Signalosome During the Cork Oak Root Response to Drought. FRONTIERS IN PLANT SCIENCE 2015; 6:1195. [PMID: 26793200 PMCID: PMC4707443 DOI: 10.3389/fpls.2015.01195] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2015] [Accepted: 12/14/2015] [Indexed: 05/09/2023]
Abstract
Quercus suber (cork oak) is a West Mediterranean species of key economic interest, being extensively explored for its ability to generate cork. Like other Mediterranean plants, Q. suber is significantly threatened by climatic changes, imposing the need to quickly understand its physiological and molecular adaptability to drought stress imposition. In the present report, we uncovered the differential transcriptome of Q. suber roots exposed to long-term drought, using an RNA-Seq approach. 454-sequencing reads were used to de novo assemble a reference transcriptome, and mapping of reads allowed the identification of 546 differentially expressed unigenes. These were enriched in both effector genes (e.g., LEA, chaperones, transporters) as well as regulatory genes, including transcription factors (TFs) belonging to various different classes, and genes associated with protein turnover. To further extend functional characterization, we identified the orthologs of differentially expressed unigenes in the model species Arabidopsis thaliana, which then allowed us to perform in silico functional inference, including gene network analysis for protein function, protein subcellular localization and gene co-expression, and in silico enrichment analysis for TFs and cis-elements. Results indicated the existence of extensive transcriptional regulatory events, including activation of ABA-responsive genes and ABF-dependent signaling. We were then able to establish that a core ABA-signaling pathway involving PP2C-SnRK2-ABF components was induced in stressed Q. suber roots, identifying a key mechanism in this species' response to drought.
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Affiliation(s)
- Alexandre P Magalhães
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Nuno Verde
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Francisca Reis
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Inês Martins
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Daniela Costa
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Teresa Lino-Neto
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Pedro H Castro
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Rui M Tavares
- BioSystems and Integrative Sciences Institute, Plant Functional Biology Center, University of Minho Braga, Portugal
| | - Herlânder Azevedo
- CIBIO, InBIO - Research Network in Biodiversity and Evolutionary Biology, Universidade do Porto Vairão, Portugal
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109
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Abstract
Reversible protein phosphorylation is an essential posttranslational modification mechanism executed by opposing actions of protein phosphatases and protein kinases. About 1,000 predicted kinases in Arabidopsis thaliana kinome predominate the number of protein phosphatases, of which there are only ~150 members in Arabidopsis. Protein phosphatases were often referred to as "housekeeping" enzymes, which act to keep eukaryotic systems in balance by counteracting the activity of protein kinases. However, recent investigations reveal the crucial and specific regulatory functions of phosphatases in cell signaling. Phosphatases operate in a coordinated manner with the protein kinases, to execute their important function in determining the cellular response to a physiological stimulus. Closer examination has established high specificity of phosphatases in substrate recognition and important roles in plant signaling pathways, such as pathogen defense and stress regulation, light and hormonal signaling, cell cycle and differentiation, metabolism, and plant growth. In this minireview we provide a compact overview about Arabidopsis protein phosphatase families, as well as members of phosphoglucan and lipid phosphatases, and highlight the recent discoveries in phosphatase research.
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Affiliation(s)
- Alois Schweighofer
- Institute of Biotechnology, University of Vilnius, V. Graičiūno 8, 02241, Vilnius, Lithuania,
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Todaka D, Shinozaki K, Yamaguchi-Shinozaki K. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants. FRONTIERS IN PLANT SCIENCE 2015; 6:84. [PMID: 25741357 PMCID: PMC4332304 DOI: 10.3389/fpls.2015.00084] [Citation(s) in RCA: 194] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 02/02/2015] [Indexed: 05/17/2023]
Abstract
Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations.
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Affiliation(s)
- Daisuke Todaka
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, TokyoJapan
| | - Kazuo Shinozaki
- RIKEN Center for Sustainable Resource Science, YokohamaJapan
| | - Kazuko Yamaguchi-Shinozaki
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, TokyoJapan
- *Correspondence: Kazuko Yamaguchi-Shinozaki, Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan e-mail:
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Zhang XL, Jiang L, Xin Q, Liu Y, Tan JX, Chen ZZ. Structural basis and functions of abscisic acid receptors PYLs. FRONTIERS IN PLANT SCIENCE 2015; 6:88. [PMID: 25745428 PMCID: PMC4333806 DOI: 10.3389/fpls.2015.00088] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2014] [Accepted: 02/02/2015] [Indexed: 05/17/2023]
Abstract
Abscisic acid (ABA) plays a key role in many developmental processes and responses to adaptive stresses in plants. Recently, a new family of nucleocytoplasmic PYR/PYL/RCAR (PYLs) has been identified as bona fide ABA receptors. PYLs together with protein phosphatases type-2C (PP2Cs), Snf1 (Sucrose-non-fermentation 1)-related kinases subfamily 2 (SnRK2s) and downstream substrates constitute the core ABA signaling network. Generally, PP2Cs inactivate SnRK2s kinases by physical interaction and direct dephosphorylation. Upon ABA binding, PYLs change their conformations and then contact and inhibit PP2Cs, thus activating SnRK2s. Here, we reviewed the recent progress in research regarding the structures of the core signaling pathways of ABA, including the (+)-ABA, (-)-ABA and ABA analogs pyrabactin as well as 6AS perception by PYLs, SnRK2s mimicking PYLs in binding PP2Cs. PYLs inhibited PP2Cs in both the presence and absence of ABA and activated SnRK2s. The present review elucidates multiple ABA signal perception and transduction by PYLs, which might shed light on how to design small chemical compounds for improving plant performance in the future.
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Affiliation(s)
- Xing L. Zhang
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical CollegeZhanjiang, China
- *Correspondence: Xing L. Zhang, Department of Pediatrics, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China e-mail:
| | - Lun Jiang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural UniversityBeijing, China
| | - Qi Xin
- National Center for Nanoscience and TechnologyBeijing, China
| | - Yang Liu
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural UniversityBeijing, China
| | - Jian X. Tan
- Department of Pediatrics, Affiliated Hospital of Guangdong Medical CollegeZhanjiang, China
| | - Zhong Z. Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural UniversityBeijing, China
- Zhong Z. Chen, State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China e-mail:
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Miyakawa T, Hatano KI, Miyauchi Y, Suwa YI, Sawano Y, Tanokura M. A secreted protein with plant-specific cysteine-rich motif functions as a mannose-binding lectin that exhibits antifungal activity. PLANT PHYSIOLOGY 2014; 166:766-78. [PMID: 25139159 PMCID: PMC4213107 DOI: 10.1104/pp.114.242636] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2014] [Accepted: 08/14/2014] [Indexed: 05/19/2023]
Abstract
Plants have a variety of mechanisms for defending against plant pathogens and tolerating environmental stresses such as drought and high salinity. Ginkbilobin2 (Gnk2) is a seed storage protein in gymnosperm that possesses antifungal activity and a plant-specific cysteine-rich motif (domain of unknown function26 [DUF26]). The Gnk2-homologous sequence is also observed in an extracellular region of cysteine-rich repeat receptor-like kinases that function in response to biotic and abiotic stresses. Here, we report the lectin-like molecular function of Gnk2 and the structural basis of its monosaccharide recognition. Nuclear magnetic resonance experiments showed that mannan was the only yeast (Saccharomyces cerevisiae) cell wall polysaccharide that interacted with Gnk2. Gnk2 also interacted with mannose, a building block of mannan, with a specificity that was similar to those of mannose-binding legume lectins, by strictly recognizing the configuration of the hydroxy group at the C4 position of the monosaccharide. The crystal structure of Gnk2 in complex with mannose revealed that three residues (asparagine-11, arginine-93, and glutamate-104) recognized mannose by hydrogen bonds, which defined the carbohydrate-binding specificity. These interactions were directly related to the ability of Gnk2 to inhibit the growth of fungi, including the plant pathogenic Fusarium spp., which were disrupted by mutation of arginine-93 or the presence of yeast mannan in the assay system. In addition, Gnk2 did not inhibit the growth of a yeast mutant strain lacking the α1,2-linked mannose moiety. These results provide insights into the molecular basis of the DUF26 protein family.
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Affiliation(s)
- Takuya Miyakawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan (T.M., Y.M., Y.Su., M.T.);Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan (K.H.); andLaboratory of Chemistry, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa-shi, Chiba 272-0827, Japan (Y.Sa.)
| | - Ken-ichi Hatano
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan (T.M., Y.M., Y.Su., M.T.);Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan (K.H.); andLaboratory of Chemistry, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa-shi, Chiba 272-0827, Japan (Y.Sa.)
| | - Yumiko Miyauchi
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan (T.M., Y.M., Y.Su., M.T.);Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan (K.H.); andLaboratory of Chemistry, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa-shi, Chiba 272-0827, Japan (Y.Sa.)
| | - You-ichi Suwa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan (T.M., Y.M., Y.Su., M.T.);Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan (K.H.); andLaboratory of Chemistry, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa-shi, Chiba 272-0827, Japan (Y.Sa.)
| | - Yoriko Sawano
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan (T.M., Y.M., Y.Su., M.T.);Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan (K.H.); andLaboratory of Chemistry, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa-shi, Chiba 272-0827, Japan (Y.Sa.)
| | - Masaru Tanokura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan (T.M., Y.M., Y.Su., M.T.);Division of Molecular Science, Faculty of Science and Technology, Gunma University, Kiryu, Gunma 376-8515, Japan (K.H.); andLaboratory of Chemistry, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa-shi, Chiba 272-0827, Japan (Y.Sa.)
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Qu Y, An Z, Zhuang B, Jing W, Zhang Q, Zhang W. Copper amine oxidase and phospholipase D act independently in abscisic acid (ABA)-induced stomatal closure in Vicia faba and Arabidopsis. JOURNAL OF PLANT RESEARCH 2014; 127:533-544. [PMID: 24817219 DOI: 10.1007/s10265-014-0633-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 03/05/2014] [Indexed: 06/03/2023]
Abstract
Recent evidence has demonstrated that both copper amine oxidase (CuAO; EC 1.4.3.6) and phospholipase D (PLD; EC 3.1.4.4) are involved in abscisic acid (ABA)-induced stomatal closure. In this study, we investigated the interaction between CuAO and PLD in the ABA response. Pretreatment with either CuAO or PLD inhibitors alone or that with both additively led to impairment of ABA-induced H2O2 production and stomatal closure in Vicia faba. ABA-stimulated PLD activation could not be inhibited by the CuAO inhibitor, and CuAO activity was not affected by the PLD inhibitor. These data suggest that CuAO and PLD act independently in the ABA response. To further examine PLD and CuAO activities in ABA responses, we used the Arabidopsis mutants cuaoζ and pldα1. Ablation of guard cell-expressed CuAOζ or PLDα1 gene retarded ABA-induced H2O2 generation and stomatal closure. As a product of PLD, phosphatidic acid (PA) substantially enhanced H2O2 production and stomatal closure in wide type, pldα1, and cuaoζ. Moreover, putrescine (Put), a substrate of CuAO as well as an activator of PLD, induced H2O2 production and stomatal closure in WT but not in both mutants. These results suggest that CuAO and PLD act independently in ABA-induced stomatal closure.
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Affiliation(s)
- Yana Qu
- College of Life Sciences, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, 210095, People's Republic of China
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Maia J, Dekkers BJW, Dolle MJ, Ligterink W, Hilhorst HWM. Abscisic acid (ABA) sensitivity regulates desiccation tolerance in germinated Arabidopsis seeds. THE NEW PHYTOLOGIST 2014; 203:81-93. [PMID: 24697728 DOI: 10.1111/nph.12785] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/19/2014] [Indexed: 05/19/2023]
Abstract
During germination, orthodox seeds lose their desiccation tolerance (DT) and become sensitive to extreme drying. Yet, DT can be rescued, in a well-defined developmental window, by the application of a mild osmotic stress before dehydration. A role for abscisic acid (ABA) has been implicated in this stress response and in DT re-establishment. However, the path from the sensing of an osmotic cue and its signaling to DT re-establishment is still largely unknown. Analyses of DT, ABA sensitivity, ABA content and gene expression were performed in desiccation-sensitive (DS) and desiccation-tolerant Arabidopsis thaliana seeds. Furthermore, loss and re-establishment of DT in germinated Arabidopsis seeds was studied in ABA-deficient and ABA-insensitive mutants. We demonstrate that the developmental window in which DT can be re-established correlates strongly with the window in which ABA sensitivity is still present. Using ABA biosynthesis and signaling mutants, we show that this hormone plays a key role in DT re-establishment. Surprisingly, re-establishment of DT depends on the modulation of ABA sensitivity rather than enhanced ABA content. In addition, the evaluation of several ABA-insensitive mutants, which can still produce normal desiccation-tolerant seeds, but are impaired in the re-establishment of DT, shows that the acquisition of DT during seed development is genetically different from its re-establishment during germination.
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Affiliation(s)
- Julio Maia
- Wageningen Seed Lab, Laboratory of Plant Physiology, Wageningen University, Wageningen, 6708 PB, the Netherlands
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115
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Khafif M, Cottret L, Balagué C, Raffaele S. Identification and phylogenetic analyses of VASt, an uncharacterized protein domain associated with lipid-binding domains in Eukaryotes. BMC Bioinformatics 2014; 15:222. [PMID: 24965341 PMCID: PMC4082322 DOI: 10.1186/1471-2105-15-222] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 06/19/2014] [Indexed: 01/25/2023] Open
Abstract
Background Several regulators of programmed cell death (PCD) in plants encode proteins with putative lipid-binding domains. Among them, VAD1 is a regulator of PCD propagation harboring a GRAM putative lipid-binding domain. However the function of VAD1 at the subcellular level is unknown and the domain architecture of VAD1 has not been analyzed in details. Results We analyzed sequence conservation across the plant kingdom in the VAD1 protein and identified an uncharacterized VASt (VAD1 Analog of StAR-related lipid transfer) domain. Using profile hidden Markov models (profile HMMs) and phylogenetic analysis we found that this domain is conserved among eukaryotes and generally associates with various lipid-binding domains. Proteins containing both a GRAM and a VASt domain include notably the yeast Ysp2 cell death regulator and numerous uncharacterized proteins. Using structure-based phylogeny, we found that the VASt domain is structurally related to Bet v1-like domains. Conclusion We identified a novel protein domain ubiquitous in Eukaryotic genomes and belonging to the Bet v1-like superfamily. Our findings open perspectives for the functional analysis of VASt-containing proteins and the characterization of novel mechanisms regulating PCD.
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Affiliation(s)
| | | | | | - Sylvain Raffaele
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441, 24 Chemin de Borde Rouge - Auzeville, CS52627, F31326 Castanet Tolosan Cedex, France.
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Abscisic acid sensor RCAR7/PYL13, specific regulator of protein phosphatase coreceptors. Proc Natl Acad Sci U S A 2014; 111:5741-6. [PMID: 24706923 DOI: 10.1073/pnas.1322085111] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The plant hormone abscisic acid (ABA) acts both as a developmental signal and as an integrator of environmental cues such as drought and cold. ABA perception recruits an ABA-binding regulatory component [regulatory component of ABA receptor (RCAR)/PYR1/PYL] and an associated protein phosphatase 2C (PP2C). Phytohormone binding inactivates the phosphatase activity of the coreceptor, permitting phosphorelay of the ABA signal via downstream protein kinases. RCARs and PP2C coreceptors are represented by small protein families comprising 14 and 9 members in Arabidopsis, respectively. The specificity of the RCAR-PP2C interaction and the constraints contributing to specific combinations are poorly understood. In this contribution, we analyzed RCAR7/PYL13, which is characterized by three variant amino acid residues in the conserved ABA-binding pocket. RCAR7 regulated the phosphatase activity of the PP2Cs ABI1, ABI2, and PP2CA in vitro at nanomolar ABA levels; however, it was unable to regulate the structurally related hypersensitive to ABA 1 (HAB1). Site-directed mutagenesis of HAB1 established ABA-dependent regulation by RCAR7. Conversion of the noncanonical amino acid residues of RCAR7 into the consensus ABA-binding pocket did not perceptibly change receptor function. Ectopic expression of RCAR7 in Arabidopsis resulted in ABA hypersensitivity affecting gene regulation, seed germination, and stomatal closure. The RCAR7 loss-of-function mutant revealed no changes in ABA responses, similar to the RCAR9 knockout line, whereas the combined deficiency of RCAR7 and RCAR9 resulted in ABA-insensitive seed germination. The study shows a role of RCAR7 in early plant development, proves its ABA receptor function, and identifies structural constraints of RCAR7-PP2C interaction.
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Nakashima K, Yamaguchi-Shinozaki K, Shinozaki K. The transcriptional regulatory network in the drought response and its crosstalk in abiotic stress responses including drought, cold, and heat. FRONTIERS IN PLANT SCIENCE 2014; 5:170. [PMID: 24904597 PMCID: PMC4032904 DOI: 10.3389/fpls.2014.00170] [Citation(s) in RCA: 438] [Impact Index Per Article: 43.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/10/2014] [Indexed: 05/17/2023]
Abstract
Drought negatively impacts plant growth and the productivity of crops around the world. Understanding the molecular mechanisms in the drought response is important for improvement of drought tolerance using molecular techniques. In plants, abscisic acid (ABA) is accumulated under osmotic stress conditions caused by drought, and has a key role in stress responses and tolerance. Comprehensive molecular analyses have shown that ABA regulates the expression of many genes under osmotic stress conditions, and the ABA-responsive element (ABRE) is the major cis-element for ABA-responsive gene expression. Transcription factors (TFs) are master regulators of gene expression. ABRE-binding protein and ABRE-binding factor TFs control gene expression in an ABA-dependent manner. SNF1-related protein kinases 2, group A 2C-type protein phosphatases, and ABA receptors were shown to control the ABA signaling pathway. ABA-independent signaling pathways such as dehydration-responsive element-binding protein TFs and NAC TFs are also involved in stress responses including drought, heat, and cold. Recent studies have suggested that there are interactions between the major ABA signaling pathway and other signaling factors in stress responses. The important roles of these TFs in crosstalk among abiotic stress responses will be discussed. Control of ABA or stress signaling factor expression can improve tolerance to environmental stresses. Recent studies using crops have shown that stress-specific overexpression of TFs improves drought tolerance and grain yield compared with controls in the field.
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Affiliation(s)
- Kazuo Nakashima
- Biological Resources and Post-harvest Division, Japan International Research Center for Agricultural SciencesTsukuba, Japan
| | - Kazuko Yamaguchi-Shinozaki
- Laboratory of Plant Molecular Physiology, Graduate School of Agricultural and Life Sciences, The University of TokyoTokyo, Japan
| | - Kazuo Shinozaki
- Gene Discovery Research Group, RIKEN Center for Sustainable Resource ScienceYokohama, Japan
- *Correspondence: Kazuo Shinozaki, Gene Discovery Research Group, RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa 230-0045, Japan e-mail:
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Rigal A, Ma Q, Robert S. Unraveling plant hormone signaling through the use of small molecules. FRONTIERS IN PLANT SCIENCE 2014; 5:373. [PMID: 25126092 PMCID: PMC4115670 DOI: 10.3389/fpls.2014.00373] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 07/11/2014] [Indexed: 05/03/2023]
Abstract
Plants have acquired the capacity to grow continuously and adjust their morphology in response to endogenous and external signals, leading to a high architectural plasticity. The dynamic and differential distribution of phytohormones is an essential factor in these developmental changes. Phytohormone perception is a fast but complex process modulating specific developmental reprogramming. In recent years, chemical genomics or the use of small molecules to modulate target protein function has emerged as a powerful strategy to study complex biological processes in plants such as hormone signaling. Small molecules can be applied in a conditional, dose-dependent and reversible manner, with the advantage of circumventing the limitations of lethality and functional redundancy inherent to traditional mutant screens. High-throughput screening of diverse chemical libraries has led to the identification of bioactive molecules able to induce plant hormone-related phenotypes. Characterization of the cognate targets and pathways of those molecules has allowed the identification of novel regulatory components, providing new insights into the molecular mechanisms of plant hormone signaling. An extensive structure-activity relationship (SAR) analysis of the natural phytohormones, their designed synthetic analogs and newly identified bioactive molecules has led to the determination of the structural requirements essential for their bioactivity. In this review, we will summarize the so far identified small molecules and their structural variants targeting specific phytohormone signaling pathways. We will highlight how the SAR analyses have enabled better interrogation of the molecular mechanisms of phytohormone responses. Finally, we will discuss how labeled/tagged hormone analogs can be exploited, as compelling tools to better understand hormone signaling and transport mechanisms.
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Affiliation(s)
| | | | - Stéphanie Robert
- *Correspondence: Stéphanie Robert, Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83 Umeå, Sweden e-mail:
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Bai G, Yang DH, Zhao Y, Ha S, Yang F, Ma J, Gao XS, Wang ZM, Zhu JK. Interactions between soybean ABA receptors and type 2C protein phosphatases. PLANT MOLECULAR BIOLOGY 2013; 83:651-64. [PMID: 23934343 PMCID: PMC3834219 DOI: 10.1007/s11103-013-0114-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 07/11/2013] [Indexed: 05/18/2023]
Abstract
The plant hormone abscisic acid (ABA) plays important roles in regulating plant growth, development, and responses to environmental stresses. Proteins in the PYR/PYL/RCAR family (hereafter referred to as PYLs) are known as ABA receptors. Since most studies thus far have focused on Arabidopsis PYLs, little is known about PYL homologs in crop plants. We report here the characterization of 21 PYL homologs (GmPYLs) in soybean. Twenty-three putative GmPYLs can be found from soybean genome sequence and categorized into three subgroups. GmPYLs interact with AtABI1 and two GmPP2Cs in diverse manners. A lot of the subgroup I GmPYLs interact with PP2Cs in an ABA-dependent manner, whereas most of the subgroup II and III GmPYLs bind to PP2Cs in an ABA-independent manner. The subgroup III GmPYL23, which cannot interact with any of the tested PP2Cs, differs from other GmPYLs. The CL2/gate domain is crucial for GmPYLs-PP2Cs interaction, and a mutation in the conserved proline (P109S) abolishes the interaction between GmPYL1 and AtABI1. Furthermore, the ABA dependence of GmPYLs-PP2Cs interactions are partially correlated with two amino acid residues preceding the CL2/gate domain of GmPYLs. We also show that GmPYL1 interacts with AtABI1 in an ABA-dependent manner in plant cells. Three GmPYLs differentially inhibit AtABI1 and GmPP2C1 in an ABA-dependent or -enhanced manner in vitro. In addition, ectopically expressing GmPYL1 partially restores ABA sensitivity of the Arabidopsis triple mutant pyr1/pyl1/pyl4. Taken together, our results suggest that soybean GmPYLs are ABA receptors that function by interacting and inhibiting PP2Cs.
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Affiliation(s)
- Ge Bai
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, P. R. China, 200240
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
| | - Da-Hai Yang
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Institute of Plant Physiology and Ecology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 200032
| | - Yang Zhao
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
| | - Si Ha
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Institute of Plant Physiology and Ecology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 200032
| | - Fen Yang
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
| | - Jun Ma
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
| | - Xiao-Su Gao
- Institute of Plant Physiology and Ecology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 200032
| | - Zhi-Min Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, P. R. China, 200240
| | - Jian-Kang Zhu
- Shanghai Center for Plant Stress Biology, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai, P. R. China, 201602
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA
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Molecular basis for the selective and ABA-independent inhibition of PP2CA by PYL13. Cell Res 2013; 23:1369-79. [PMID: 24165892 DOI: 10.1038/cr.2013.143] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 08/28/2013] [Accepted: 08/30/2013] [Indexed: 12/13/2022] Open
Abstract
PYR1/PYL/RCAR family proteins (PYLs) are well-characterized abscisic acid (ABA) receptors. Among the 14 PYL members in Arabidopsis thaliana, PYL13 is ABA irresponsive and its function has remained elusive. Here, we show that PYL13 selectively inhibits the phosphatase activity of PP2CA independent of ABA. The crystal structure of PYL13-PP2CA complex, which was determined at 2.4 Å resolution, elucidates the molecular basis for the specific recognition between PP2CA and PYL13. In addition to the canonical interactions between PYLs and PP2Cs, an extra interface is identified involving an element in the vicinity of a previously uncharacterized CCCH zinc-finger (ZF) motif in PP2CA. Sequence blast identified another 56 ZF-containing PP2Cs, all of which are from plants. The structure also reveals the molecular determinants for the ABA irresponsiveness of PYL13. Finally, biochemical analysis suggests that PYL13 may hetero-oligomerize with PYL10. These two PYLs antagonize each other in their respective ABA-independent inhibitions of PP2Cs. The biochemical and structural studies provide important insights into the function of PYL13 in the stress response of plant and set up a foundation for future biotechnological applications of PYL13.
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A thermoacidophile-specific protein family, DUF3211, functions as a fatty acid carrier with novel binding mode. J Bacteriol 2013; 195:4005-12. [PMID: 23836863 DOI: 10.1128/jb.00432-13] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
STK_08120 is a member of the thermoacidophile-specific DUF3211 protein family from Sulfolobus tokodaii strain 7. Its molecular function remains obscure, and sequence similarities for obtaining functional remarks are not available. In this study, the crystal structure of STK_08120 was determined at 1.79-Å resolution to predict its probable function using structure similarity searches. The structure adopts an α/β structure of a helix-grip fold, which is found in the START domain proteins with cavities for hydrophobic substrates or ligands. The detailed structural features implied that fatty acids are the primary ligand candidates for STK_08120, and binding assays revealed that the protein bound long-chain saturated fatty acids (>C14) and their trans-unsaturated types with an affinity equal to that for major fatty acid binding proteins in mammals and plants. Moreover, the structure of an STK_08120-myristic acid complex revealed a unique binding mode among fatty acid binding proteins. These results suggest that the thermoacidophile-specific protein family DUF3211 functions as a fatty acid carrier with a novel binding mode.
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Abstract
Abscisic acid (ABA) is one of the "classical" plant hormones, i.e. discovered at least 50 years ago, that regulates many aspects of plant growth and development. This chapter reviews our current understanding of ABA synthesis, metabolism, transport, and signal transduction, emphasizing knowledge gained from studies of Arabidopsis. A combination of genetic, molecular and biochemical studies has identified nearly all of the enzymes involved in ABA metabolism, almost 200 loci regulating ABA response, and thousands of genes regulated by ABA in various contexts. Some of these regulators are implicated in cross-talk with other developmental, environmental or hormonal signals. Specific details of the ABA signaling mechanisms vary among tissues or developmental stages; these are discussed in the context of ABA effects on seed maturation, germination, seedling growth, vegetative stress responses, stomatal regulation, pathogen response, flowering, and senescence.
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Affiliation(s)
- Ruth Finkelstein
- Department of Molecular, Cellular and Developmental Biology, University of California at Santa Barbara, Santa Barbara, CA 93106 Address
- correspondence to e-mail:
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