title: Arabidopsis HY1-Modulated Stomatal Movement: An Integrative Hub Is Functionally Associated with ABI4 in Dehydration-Induced ABA Responsiveness.
abstract: Heme oxygenase (HO; EC 1.14.99.3) has recently been proposed as a novel component in mediating wide ranges of the plant adaptive signaling processes. However, the physiological significance and molecular basis underlying Arabidopsis (Arabidopsis thaliana) HO1 (HY1) functioning in drought tolerance remained unclear. Here, we report that mutation of HY1 promoted, but overexpression of this gene impaired, Arabidopsis drought tolerance. This was attributed to the abscisic acid (ABA)-hypersensitive or -hyposensitive phenotypes, with the regulation of stomatal closure in particular. However, comparative transcriptomic profile analysis showed that the induction of numerous ABA/stress-dependent genes in dehydrated wild-type plants was differentially impaired in the hy1 mutant. In agreement, ABA-induced ABSCISIC ACID-INSENSITIVE4 (ABI4) transcript accumulation was strengthened in the hy1 mutant. Genetic analysis further identified that the hy1-associated ABA hypersensitivity and drought tolerance were arrested in the abi4 background. Moreover, the promotion of ABA-triggered up-regulation of RbohD abundance and reactive oxygen species (ROS) levels in the hy1 mutant was almost fully blocked by the mutation of ABI4, suggesting that the HY1-ABI4 signaling in the wild type involved in stomatal closure was dependent on the RbohD-derived ROS production. However, hy1-promoted stomatal closure was not affected by a nitric oxide scavenger. Correspondingly, ABA-insensitive behaviors in rbohD stomata were not affected by either the mutation of HY1 or its ectopic expression in the rbohD background, both of which responded significantly to exogenous ROS. These data indicate that HY1 functioned negatively and acted upstream of ABI4 in drought signaling, which was casually dependent on the RbohD-derived ROS in the regulation of stomatal closure.
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Yanjie
authors.initials: Y
authors.lastname: Xie
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Mao
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Xingliang
authors.initials: X
authors.lastname: Duan
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Zhou
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Diwen
authors.initials: D
authors.lastname: Lai
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
authors.forename: Yihua
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: College of Life Sciences, Laboratory Center of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China wbshenh@njau.edu.cn.
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Shen
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism / Q000494:pharmacology*; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003681:Dehydration; D055864:Droughts; D020869:Gene Expression Profiling / Q000379:methods; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics* / Q000378:metabolism; D018613:Microscopy, Confocal; D009154:Mutation; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology; D054046:Plant Stomata / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: C470421:ABI4 protein, Arabidopsis; D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D000040:Abscisic Acid; C585690:HY1 protein, Arabidopsis; D006419:Heme Oxygenase (Decyclizing); C568857:AT5G47910 protein, Arabidopsis; D019255:NADPH Oxidases