title: Involvement of genes encoding ABI1 protein phosphatases in the response of Brassica napus L. to drought stress.
abstract: In this report we characterized the Arabidopsis ABI1 gene orthologue and Brassica napus gene paralogues encoding protein phosphatase 2C (PP2C, group A), which is known to be a negative regulator of the ABA signaling pathway. Six homologous B. napus sequences were identified and characterized as putative PP2C group A members. To gain insight into the conservation of ABI1 function in Brassicaceae, and understand better its regulatory effects in the drought stress response, we generated transgenic B. napus plants overexpressing A. thaliana ABI1. Transgenic plants subjected to drought showed a decrease in relative water content, photosynthetic pigments content and expression level of RAB18- and RD19A-drought-responsive marker genes relative to WT plants. We present the characterization of the drought response of B. napus with the participation of ABI1-like paralogues. The expression pattern of two evolutionarily distant paralogues, BnaA01.ABI1.a and BnaC07.ABI1.b in B. napus and their promoter activity in A. thaliana showed differences in the induction of the paralogues under dehydration stress. Comparative sequence analysis of both BnaABI1 promoters showed variation in positions of cis-acting elements that are especially important for ABA- and stress-inducible expression. Together, these data reveal that subfunctionalization following gene duplication may be important in the maintenance and functional divergence of the BnaABI1 paralogues. Our results provide a framework for a better understanding of (1) the role of ABI1 as a hub protein regulator of the drought response, and (2) the differential involvement of the duplicated BnaABI1 genes in the response of B. napus to dehydration-related stresses.
authors.affiliation: Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, 60-479, Poznan, Poland, dbab@igr.poznan.pl.
authors.forename: Danuta
authors.initials: D
authors.lastname: Babula-Skowrońska
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Ludwików
authors.forename: Agata
authors.initials: A
authors.lastname: Cieśla
authors.forename: Anna
authors.initials: A
authors.lastname: Olejnik
authors.forename: Teresa
authors.initials: T
authors.lastname: Cegielska-Taras
authors.forename: Iwona
authors.initials: I
authors.lastname: Bartkowiak-Broda
authors.forename: Jan
authors.initials: J
authors.lastname: Sadowski
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D029688:Brassica napus / Q000235:genetics* / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism; D018744:DNA, Plant / Q000235:genetics; D055864:Droughts; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D010749:Phosphoprotein Phosphatases / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D000071636:Protein Phosphatase 2C; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D018744:DNA, Plant; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011994:Recombinant Proteins; D014867:Water; D002734:Chlorophyll; D000040:Abscisic Acid; C087434:ABI1 protein, Arabidopsis; D010749:Phosphoprotein Phosphatases; D000071636:Protein Phosphatase 2C