Abstract
Recently, the SNF1-related protein kinase 2 (SnRK2) family is highlighted because several SnRK2s have been identified as key mediators of ABA signaling. To survey the biological functions of 10 members of SnRK2 family (SRK2A-J) in Arabidopsis, we constructed pBE2113 binary vectors harboring SnRK2-GFP fusion fragments and introduced them into T87 Arabidopsis cells. As a result of in-gel kinase assay using those cell lines, the activation of SRK2C by osmotic- and cold-stress was detected. RNA gel-blot analysis revealed that SRK2C was mainly expressed in roots, and its expression was induced by cold stress. The SRK2C-GFP over-expressing transgenic plants (SRK2C-ox) exhibited delay of volting and flowering, and their freezing and drought tolerance was dramatically reinforced. In SRK2C-ox, some stress-responsive mRNAs were more abundant than control plants, indicating that those genes might confer to stress tolerance. Our results suggest that SRK2C is a positive regulator of stress signaling in Arabidopsis.
