title: Arabidopsis thaliana RECEPTOR DEAD KINASE1 Functions as a Positive Regulator in Plant Responses to ABA.
abstract: Abscisic acid (ABA) is a major phytohormone involved in important stress-related and developmental plant processes. Membrane-delimited ABA signal transduction plays an important role in early ABA signaling, but the molecular mechanisms connecting core signaling components to the plasma membrane remain unclear. Plants have evolved a large number of receptor-like kinases (RLKs) to modulate diverse biological processes by perceiving extracellular stimuli and activating downstream signaling responses. In this study, a putative leucine-rich repeat-RLK gene named RECEPTOR DEAD KINASE1 (AtRDK1) was identified and characterized in Arabidopsis thaliana. RDK1 promoter-GUS analysis revealed that RDK1 is expressed ubiquitously in the various tissues in Arabidopsis, and its expression is mainly induced by ABA. In the presence of ABA, RDK1-deficient rdk1-1 and rdk1-2 lines showed significant resistance in cotyledon greening and root growth, whereas RDK1-overexpressing lines showed enhanced sensitivity. Consistently, the expression of ABA-responsive genes was significantly downregulated in rdk1 mutant seedlings, which were also hypersensitive to drought stress with increased water loss. Interestingly, RDK1 was found to be an atypical kinase localized to the plasma membrane and did not require its kinase activity during ABA-mediated inhibition of seedling development. Accordingly, RDK1 interacted in the plasma membrane with type 2C protein phosphatase ABSCISIC ACID INSENSITIVE1 (ABI1); this interaction was further enhanced by exogenous application of ABA, suggesting that RDK1-mediated recruitment of ABI1 onto the plasma membrane is important for ABA signaling. Taken together, these results reveal an important role for RDK1 in plant responses to abiotic stress conditions in an ABA-dependent manner.
authors.affiliation: Division of Applied Life Sciences, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Dhinesh
authors.initials: D
authors.lastname: Kumar
authors.affiliation: Division of Applied Life Sciences, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Ritesh
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Division of Applied Life Sciences, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Dongwon
authors.initials: D
authors.lastname: Baek
authors.affiliation: Department of Industrial Plant Science and Technology, College of Agricultural, Life and Environmental Sciences, Chungbuk National University, Cheongju 28644, Korea.
authors.forename: Tae-Kyung
authors.initials: TK
authors.lastname: Hyun
authors.affiliation: Division of Applied Life Sciences, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Woo Sik
authors.initials: WS
authors.lastname: Chung
authors.affiliation: Division of Applied Life Sciences, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea. Electronic address: djyun@gnu.ac.kr.
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
authors.affiliation: Division of Applied Life Sciences, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea. Electronic address: kimjy@gnu.ac.kr.
authors.forename: Jae-Yean
authors.initials: JY
authors.lastname: Kim
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002462:Cell Membrane; D055864:Droughts; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018525:Germination / Q000502:physiology; D009154:Mutation; D009997:Osmotic Pressure; D010712:Phosphatidic Acids / Q000378:metabolism; D000072417:Protein Domains; D011494:Protein Kinases / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D010712:Phosphatidic Acids; D000040:Abscisic Acid; C000621495:AT4G34220 protein, Arabidopsis; D011494:Protein Kinases
keywords: ABA; Arabidopsis; abiotic stress; atypical kinases; protein phosphatases; receptor-like kinases