Abstract
Abscisic acid (ABA) is a phytohormone that regulates seed dormancy, germination and stress responses in plants. Our group had identified the SNF1-related protein kinase 2 (SnRK2) family as ABA-activated protein kinases which positively regulates ABA signaling. On the other hand, ABI-type protein phosphase 2C, e.g. ABI1 or ABI2, had been known as negative regulators for ABA signaling. Therefore, we supposed that SnRK2 and PP2C have some symmetric relationships each other. To confirm this idea, we checked protein-protein interactions by yeast two-hybrid assay and found several specific interactions between SnRK2 and PP2C. Transient BiFC assay or Co-IP confirmed SnRK2-PP2C interaction in vivo. Furthermore, subcellular localizations or gene expression patterns suggested functional interactions of each SnRK2 and PP2C. We will discuss about the regulatory mechanism of ABA signaling by SnRK2-PP2C complexes.
