Role of AREB/ABF-SnRK2 pathway in ABA signaling in response to water stress

Abstract

In plants, under drought stress conditions, ABA levels increase, and then the ABA regulates the expression of many genes that function in the stress tolerance. In the presence of ABA, PYR/PYL/RCAR family START proteins that function as ABA receptors recognize and bind to group-A protein phosphatases 2C (PP2Cs). Then SNF1-related protein kinases (SnRK2s) are released from the PP2C-dependent negative regulation, which allows the subclass III of SnRK2s (SRK2D/SnRK2.2, SRK2E/SnRK2.6, and SRK2I/SnRK2.3) to regulate downstream transcription factors such as AREB/ABFs (AREB1/ABF2, AREB2/ABF4, and ABF3) and activate ABA-responsive gene expression or other ABA-related responses. In this study, based on the molecular characterization of both AREB/ABF transcription factors and SnRK2 protein kinases, we will discuss the role of the AREB/ABF-SnRK2 pathway in ABA signaling in response to water stress in Arabidopsis and rice.