title: A nuclear-localized protein, KOLD SENSITIV-1, affects the expression of cold-responsive genes during prolonged chilling in Arabidopsis.
abstract: Plants respond to cold by transcriptional and metabolic responses which underlie tolerance and acclimation mechanisms, but details at the molecular level are incomplete. Here we describe KOLD SENSITIV-1 (KOS1), a new gene required for responses to cold. KOS1 protein is predicted to have coiled-coil, Structural Maintenance of Chromosomes and nuclear-targeting domains. GFP-labeled KOS1 localizes to the nucleus. Null mutants could not be isolated but two independent knockdown T-DNA mutants were obtained. Growth and development of kos1 knockdown mutant plants was comparable to wild type when grown at 21°C. However, when grown at 4°C these mutants exhibited accelerated leaf yellowing and smaller rosette size than wild type. Quantitative RT-PCR revealed that in the cold kos1 mutants had reduced expression of cold-responsive transcripts COR15A, COR15B, BAM3 and AMY3. Metabolite profiling revealed that ascorbate levels were lower in the mutants in the cold relative to wild type. KOS1 therefore represents a new gene that influences the regulation of transcript and metabolite levels in response to prolonged chilling temperatures.
authors.affiliation: Australian Research Council Centre of Excellence in Plant Energy Biology, The University of Western Australia, Stirling Highway, Crawley, Perth, Western Australia, 6009, Australia.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Purdy
authors.forename: John D
authors.initials: JD
authors.lastname: Bussell
authors.forename: David C
authors.initials: DC
authors.lastname: Nelson
authors.forename: Dorthe
authors.initials: D
authors.lastname: Villadsen
authors.forename: Steven M
authors.initials: SM
authors.lastname: Smith
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism*; D001205:Ascorbic Acid / Q000378:metabolism; D003080:Cold Temperature; D008401:Gas Chromatography-Mass Spectrometry; D018506:Gene Expression Regulation, Plant; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; D010940:Plant Proteins; D013213:Starch; D001205:Ascorbic Acid