The GhMPK7‐GhSDIRIP1 module enhances drought tolerance in cotton by regulating ABA signaling

Summary The phytohormone abscisic acid (ABA) is important during abiotic stresses, especially drought stress. Although mitogen‐activated protein kinase (MAPK) cascades are crucial for ABA‐mediated drought tolerance, how these cascades integrate and deliver the downstream ABA signals is poorly understood. Here, the group C MAPK GhMPK7 was found to positively regulate ABA‐mediated drought tolerance in cotton. Silencing GhMPK7 decreased drought tolerance in transgenic cotton plants. After ABA treatment, the GhMPK7 ‐silenced transgenic plants were not sensitive to ABA, exhibited restricted stomatal closure, faster germination rates and longer roots. Importantly, GhSDIRIP1, a negative regulator of ABA signaling, was found to interact with GhMPK7 as a downstream. Silencing GhSDIRIP1 in GhMPK7 ‐silenced transgenic cotton plants restored the drought‐intolerant phenotype caused by GhMPK7 silencing. The results of the phosphorylation experiments revealed that GhMPK7 can phosphorylate the Ser‐19 residue of GhSDIRIP1 to regulate its stability. GhMPK7‐induced GhSDIRIP1 protein degradation increased ABA signaling intensity in response to drought stress. Overall, our findings provide insights into the positive regulatory mechanism of ABA‐involved drought tolerance, which is mediated by the GhMPK7‐GhSDIRIP1 module. This study expands our knowledge of how MAPK cascades regulate the intensity of ABA‐mediated drought tolerance in plants and advances our understanding of the interplay between phosphorylation and ubiquitination.