title: Arabidopsis decuple mutant reveals the importance of SnRK2 kinases in osmotic stress responses in vivo.
abstract: Osmotic stress associated with drought or salinity is a major factor that limits plant productivity. Protein kinases in the SNF1-related protein kinase 2 (SnRK2) family are activated by osmotic stress, suggesting that the kinases are involved in osmotic stress signaling. However, due to functional redundancy, their contribution to osmotic stress responses remained unclear. In this report, we constructed an Arabidopsis line carrying mutations in all 10 members of the SnRK2 family. The decuple mutant snrk2.1/2/3/4/5/6/7/8/9/10 grew poorly under hyperosmotic stress conditions but was similar to the wild type in culture media in the absence of osmotic stress. The mutant was also defective in gene regulation and the accumulation of abscisic acid (ABA), proline, and inositol 1,4,5-trisphosphate under osmotic stress. In addition, analysis of mutants defective in the ABA-activated SnRK2s (snrk2.2/3/6) and mutants defective in the rest of the SnRK2s (snrk2.1/4/5/7/8/9/10) revealed that SnRK2s are a merging point of ABA-dependent and -independent pathways for osmotic stress responses. These results demonstrate critical functions of the SnRK2s in mediating osmotic stress signaling and tolerance.
authors.affiliation: Department of Botany and Plant Sciences, University of California, Riverside, CA 92521, USA.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Fujii
authors.forename: Paul E
authors.initials: PE
authors.lastname: Verslues
authors.forename: Jian-Kang
authors.initials: JK
authors.lastname: Zhu
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D020869:Gene Expression Profiling; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D009997:Osmotic Pressure / Q000502:physiology; D010937:Plant Growth Regulators / Q000494:pharmacology; D011392:Proline / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D010937:Plant Growth Regulators; C492978:SnRK2 protein, Arabidopsis; D000040:Abscisic Acid; D015544:Inositol 1,4,5-Trisphosphate; D011392:Proline; D011494:Protein Kinases; C556416:SnRK2.10 protein, Arabidopsis; C472139:OST1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases