Functional Analysis of Osmotic Stress- Activated SnRK2b Protein Kinases in Arabidopsis

Abstract

SNF1-related protein kinases 2 (SnRK2s) are activated by ABA- and/or osmotic-stress and are involved in stress signaling pathways in Arabidopsis. There are two subgroups, SnRK2a and SnRK2b, and contains 10 genes in Arabidopsis genome. Although SnRK2a has been shown to be important roles for ABA responses, our knowledge about SnRK2b subfamily is still limited. In-gel kinase assay showed that one of SnRK2b member, SRK2G, is activated very rapidly within 30 seconds by osmotic stress such as salt or mannitol but not by ABA. To explore physiological functions of SnRK2b, we isolated two independent T-DNA insertional mutants for each SnRK2b gene. In addition, we prepared double, triple or quadruple SnRK2b mutants, because SnRK2b are expected to be functional redundant. Now we are performing phenotypic analysis, in-gel kinase assay, and microarray analysis using these multiple mutants.