title: Overexpression of an Arabidopsis cysteine-rich receptor-like protein kinase, CRK5, enhances abscisic acid sensitivity and confers drought tolerance.
abstract: Receptor-like kinases (RLKs) have been reported to regulate many developmental and defense process, but only a few members have been functionally characterized. In the present study, our observations suggest that one of the RLKs, a membrane-localized cysteine-rich receptor-like protein kinase, CRK5, is involved in abscisic acid (ABA) signaling in Arabidopsis thaliana Overexpression of CRK5 increases ABA sensitivity in ABA-induced early seedling growth arrest and promotion of stomatal closure and inhibition of stomatal opening. Interestingly, and importantly, overexpression of CRK5 enhances plant drought tolerance without affecting plant growth at the mature stages and plant productivity. Transgenic lines overexpressing a mutated form of CRK5, CRK5 (K372E) with the change of the 372nd conserved amino acid residue from lysine to glutamic acid in its kinase domain, result in wild-type ABA and drought responses, supporting the role of CRK5 in ABA signaling. The loss-of-function mutation of the CRK5 gene does not affect the ABA response, while overexpression of two homologs of CRK5, CRK4 and CRK19, confers ABA responses, suggesting that these CRK members function redundantly. We further showed that WRKY18, WRKY40 and WRKY60 transcription factors repress the expression of CRK5, and that CRK5 likely functions upstream of ABI2 in ABA signaling. These findings help in understanding the complex ABA signaling network.
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Lu
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Liang
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Wu
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Bi
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
authors.forename: Yong-Tao
authors.initials: YT
authors.lastname: Yu
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China zhangdp@tsinghua.edu.cn wangxf@biomed.tsinghua.edu.cn.
authors.forename: Xiao-Fang
authors.initials: XF
authors.lastname: Wang
authors.affiliation: Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China zhangdp@tsinghua.edu.cn wangxf@biomed.tsinghua.edu.cn.
authors.forename: Da-Peng
authors.initials: DP
authors.lastname: Zhang
mesh_terms: D000040:Abscisic Acid / Q000502:physiology*; D017360:Arabidopsis / Q000378:metabolism* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000502:physiology*; D003681:Dehydration / Q000378:metabolism / Q000503:physiopathology; D024202:Electrophoretic Mobility Shift Assay; D004926:Escherichia coli; D010937:Plant Growth Regulators / Q000502:physiology*; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases / Q000502:physiology*; D060888:Real-Time Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000502:physiology*; D014026:Nicotiana; D020798:Two-Hybrid System Techniques
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; D000040:Abscisic Acid; C420215:CRK5 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: ABI2; CRK5; WRKY18; WRKY40; WRKY60.; abscisic acid; drought tolerance; receptor-like kinase