title: Arabidopsis type B cytokinin response regulators ARR1, ARR10, and ARR12 negatively regulate plant responses to drought.
abstract: In this study, we used a loss-of-function approach to elucidate the functions of three Arabidopsis type B response regulators (ARRs)--namely ARR1, ARR10, and ARR12--in regulating the Arabidopsis plant responses to drought. The arr1,10,12 triple mutant showed a significant increase in drought tolerance versus WT plants, as indicated by its higher relative water content and survival rate on drying soil. This enhanced drought tolerance of arr1,10,12 plants can be attributed to enhanced cell membrane integrity, increased anthocyanin biosynthesis, abscisic acid (ABA) hypersensitivity, and reduced stomatal aperture, but not to altered stomatal density. Further drought-tolerance tests of lower-order double and single mutants indicated that ARR1, ARR10, and ARR12 negatively and redundantly control plant responses to drought, with ARR1 appearing to bear the most critical function among the three proteins. In agreement with these findings, a comparative genome-wide analysis of the leaves of arr1,10,12 and WT plants under both normal and dehydration conditions suggested a cytokinin (CK) signaling-mediated network controlling plant adaptation to drought via many dehydration/drought- and/or ABA-responsive genes that can provide osmotic adjustment and protection to cellular and membrane structures. Expression of all three ARR genes was repressed by dehydration and ABA treatments, inferring that plants down-regulate these genes as an adaptive mechanism to survive drought. Collectively, our results demonstrate that repression of CK response, and thus CK signaling, is one of the strategies plants use to cope with water deficit, providing novel insight for the design of drought-tolerant plants by genetic engineering.
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan;
authors.forename: Kien Huu
authors.initials: KH
authors.lastname: Nguyen
authors.affiliation: National Key Laboratory of Plant Cell Biotechnology, Agricultural Genetics Institute, Vietnamese Academy of Agricultural Science, Hanoi 100000, Vietnam;
authors.forename: Chien Van
authors.initials: CV
authors.lastname: Ha
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan;
authors.forename: Rie
authors.initials: R
authors.lastname: Nishiyama
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan;
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Watanabe
authors.affiliation: Department of Applied Biotechnology, StelaGenomics México, Irapuato, Guanajuato 36821, Mexico;
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Leyva-González
authors.affiliation: Biological Resources and Post-Harvest Division, Japan International Research Center for Agricultural Sciences, Tsukuba, Ibaraki 305-8686, Japan;
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Fujita
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan;
authors.forename: Uven Thi
authors.initials: UT
authors.lastname: Tran
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan;
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Li
authors.affiliation: Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan;
authors.forename: Maho
authors.initials: M
authors.lastname: Tanaka
authors.affiliation: Plant Genomic Network Research Team, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan; Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology (JST), Kawaguchi, Saitama 332-0012, Japan;
authors.forename: Motoaki
authors.initials: M
authors.lastname: Seki
authors.affiliation: Department of Biological Sciences, Dartmouth College, Hanover, NH 03755;
authors.forename: G Eric
authors.initials: GE
authors.lastname: Schaller
authors.affiliation: Laboratorio Nacional de Genómica para la Biodiversidad (Langebio)/Unidad de Genómica Avanzada, Centro de Investigación y Estudios Avanzados del Instituto Politécnico Nacional, Irapuato, Guanajuato 36500, Mexico lherrera@langebio.cinvestav.mx son.tran@riken.jp.
authors.forename: Luis
authors.initials: L
authors.lastname: Herrera-Estrella
authors.affiliation: Signaling Pathway Research Unit, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan; lherrera@langebio.cinvestav.mx son.tran@riken.jp.
authors.forename: L S
authors.initials: LS
authors.lastname: Tran
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology / Q000502:physiology; D000222:Adaptation, Physiological / Q000235:genetics / Q000502:physiology*; D000872:Anthocyanins / Q000096:biosynthesis; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000648:ultrastructure; D003583:Cytokinins / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D055864:Droughts; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D018515:Plant Leaves / Q000502:physiology / Q000648:ultrastructure; D018520:Plant Shoots / Q000378:metabolism; D054046:Plant Stomata / Q000502:physiology; D015398:Signal Transduction; D014157:Transcription Factors / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D059467:Transcriptome
chemical_list: C117138:ARR1 protein, Arabidopsis; C469257:ARR10 protein, Arabidopsis; C519632:ARR12 protein, Arabidopsis; D000872:Anthocyanins; D029681:Arabidopsis Proteins; D003583:Cytokinins; D004268:DNA-Binding Proteins; D014157:Transcription Factors; D000040:Abscisic Acid
keywords: comparative transcriptome analysis; cytokinin signaling; drought adaption; type B response regulators