title: Analysis of ABA hypersensitive germination2 revealed the pivotal functions of PARN in stress response in Arabidopsis.
abstract: Accumulating evidence suggests that mRNA degradation systems are crucial for various biological processes in eukaryotes. Here we provide evidence that an mRNA degradation system is associated with some plant hormones and stress responses in plants. We analysed a novel Arabidopsis abscisic acid (ABA)-hypersensitive mutant, ahg2-1, that showed ABA hypersensitivity not only in germination, but also at later developmental stages, and that displayed pleiotropic phenotypes. We found that ahg2-1 accumulated more endogenous ABA in seeds and mannitol-treated plants than did the wild type. Microarray experiments showed that the expressions of ABA-, salicylic acid- and stress-inducible genes were increased in normally grown ahg2-1 plants, suggesting that the ahg2-1 mutation somehow affects various stress responses as well as ABA responses. Map-based cloning of AHG2 revealed that this gene encodes a poly(A)-specific ribonuclease (AtPARN) that is presumed to function in mRNA degradation. Detailed analysis of the ahg2-1 mutation suggests that the mutation reduces AtPARN production. Interestingly, expression of AtPARN was induced by treatment with ABA, high salinity and osmotic stress. These results suggest that both upregulation and downregulation of gene expression by the mRNA-destabilizing activity of AtPARN are crucial for proper ABA, salicylic acid and stress responses.
authors.affiliation: Graduate School of Integrated Science, Yokohama City University, 1-7-29 Suehiro, Tsurumi, Yokohama 230-0045, Japan.
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Nishimura
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Kitahata
authors.forename: Motoaki
authors.initials: M
authors.lastname: Seki
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Narusaka
authors.forename: Mari
authors.initials: M
authors.lastname: Narusaka
authors.forename: Takashi
authors.initials: T
authors.lastname: Kuromori
authors.forename: Tadao
authors.initials: T
authors.lastname: Asami
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shinozaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirayama
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D017398:Alternative Splicing; D017360:Arabidopsis / Q000033:anatomy & histology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D005095:Exoribonucleases / Q000235:genetics* / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D008954:Models, Biological; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000033:anatomy & histology / Q000201:enzymology / Q000235:genetics; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D020156:Salicylic Acid / Q000378:metabolism
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D005095:Exoribonucleases; D012333:RNA, Messenger; D020156:Salicylic Acid