Abstract
Protein phosphorylation/dephosphorylation are major signaling events induced by osmotic stress in higher plants. Recently, we found that the SNF1-related protein kinase 2 (SnRK2) family was activated by ABA or hyper osmolarity. There are ten members (SRK2A-J) of SnRK2 in Arabidopsis and one of these, SRK2E/OST1, is an ABA-activated protein kinase which regulates stomatal closure. In addition, SRK2C is an osmotic stress-activated protein kinase that can significantly impact drought tolerance in Arabidopsis. Although both SRK2E and SRK2C are classified into SnRK2a subfamily, there are four SnRK2b subfamily in Arabidopsis and they have not been fully investigated yet. Here, we investigated one of Arabidopsis SnRK2b, SRK2G, for its activation or expression pattern in Arabidopsis. In-gel kinase assay showed that SRK2G was rapidly activated by osmotic stress within 30 seconds, and expression analysis revealed constitutive expression of SRK2G in Arabidopsis. We are now analyzing SRK2G-overexpressing plants and its T-DNA insertional mutants.
