A rice calmodulin-like protein OsCML27 participates in drought tolerance by fine-tuning OsRbohB-mediated ROS signaling

Source: PubMed Central Open Access, NCBI / U.S. National Library of Medicine

Respiratory burst oxidase homolog (RBOH)–based ROS production was widely verified playing vital roles in plant stress responses; however, its inhibitory mechanism remains largely unknown. Here, we demonstrate that a calmodulin-like (CML) protein OsCML27 functions as a flexible brake of OsRbohB-mediated ROS production to regulate rice drought tolerance via an OsMRLK63-OsCML27-OsRbohB module. OsCML27 negatively regulates drought tolerance of rice where the overexpression lines showed a faster water loss rate and a lower survival rate under drought, while themutants exhibited a slower dehydration rate and a slightly lower survival rate as compared to wild type. OsCML27 can interact with and be phosphorylated by a receptor-like kinase OsMRLK63 primarily at Ser, and the phosphorylation level could be increased by drought. The phosphorylation by OsMRLK63 enhances OsCML27 stability, and OsCML27 inhibits ROS production by interacting with OsRbohB in the Ca-dependent manner. All these results reveal that OsCML27 integrates phosphorylation and Casignals to regulate drought tolerance of rice by fine-tuning OsRbohB-mediated ROS signaling. Calmodulin-like protein OsCML27 acts as a flexible brake of OsRbohB-mediated ROS production for drought tolerance of rice. teaser