title: Functional analyses of the ABI1-related protein phosphatase type 2C reveal evolutionarily conserved regulation of abscisic acid signaling between Arabidopsis and the moss Physcomitrella patens.
abstract: We employed a comparative genomic approach to understand protein phosphatase 2C (PP2C)-mediated abscisic acid (ABA) signaling in the moss Physcomitrella patens. Ectopic expression of Arabidopsis (Arabidopsis thaliana) abi1-1, a dominant mutant allele of ABI1 encoding a PP2C involved in the negative regulation of ABA signaling, caused ABA insensitivity of P. patens both in gene expression of late embryogenesis abundant (LEA) genes and in ABA-induced protonemal growth inhibition. The transgenic abi1-1 plants showed decreased ABA-induced freezing tolerance, and decreased tolerance to osmotic stress. Analyses of the P. patens genome revealed that only two (PpABI1A and PpABI1B) PP2C genes were related to ABI1. In the ppabi1a null mutants, ABA-induced expression of LEA genes was elevated, and protonemal growth was inhibited with lower ABA concentration compared to the wild type. Moreover, ABA-induced freezing tolerance of the ppabi1a mutants was markedly enhanced. We provide the genetic evidence that PP2C-mediated ABA signaling is evolutionarily conserved between Arabidopsis and P. patens.
authors.affiliation: Department of Bioscience, Tokyo University of Agriculture, Setagaya-ku, Tokyo, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Komatsu
authors.forename: Yuri
authors.initials: Y
authors.lastname: Nishikawa
authors.forename: Tomohito
authors.initials: T
authors.lastname: Ohtsuka
authors.forename: Teruaki
authors.initials: T
authors.lastname: Taji
authors.forename: Ralph S
authors.initials: RS
authors.lastname: Quatrano
authors.forename: Shigeo
authors.initials: S
authors.lastname: Tanaka
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Sakata
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D019068:Bryopsida / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D010749:Phosphoprotein Phosphatases / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D000071636:Protein Phosphatase 2C; D018749:RNA, Plant / Q000235:genetics; D015398:Signal Transduction; D013312:Stress, Physiological
chemical_list: D029681:Arabidopsis Proteins; D018749:RNA, Plant; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C