Phosphorylation of bip130 by OsMPK1 regulates abscisic acid-induced antioxidant defense in rice

Abstract In rice ( Oryza sativa ), the mitogen-activated protein kinase 1, OsMPK1, has been shown to play an important role in abscisic acid (ABA)-induced antioxidant defense and to enhance the tolerance of plants to drought, salinity and oxidative stress. However, its downstream molecular mechanisms are poorly understood. Here, we identified a BRI1-KD interacting protein 130, bip130, which interacts with OsMPK1 in vitro and in vivo. A transient expression analysis in combination with mutant analysis in rice protoplasts revealed that bip130 is required for ABA-induced antioxidant defense in an OsMPK1-dependent manner. Furthermore, bip130 can be phosphorylated by OsMPK1 at Thr-153 in vitro, and Thr-153 is essential for the ABA-induced antioxidant defense by OsMPK1. These results reveal that OsMPK1 phosphorylates bip130 at Thr-153 to regulate ABA-induced antioxidant defense.