The OsCBL8–OsCIPK17 Module Regulates Seedling Growth and Confers Resistance to Heat and Drought in Rice

The calcium signaling pathway is critical for plant growth, development, and response to external stimuli. The CBL–CIPK pathway has been well characterized as a calcium-signaling pathway. However, in most reports, only a single function for this module has been described. Here, we examined multiple functions of this module. CIPK showed a similar distribution to that of CBL, and OsCBL and OsCIPK families were retained after experiencing whole genome duplication events through the phylogenetic and synteny analysis. This study found that OsCBL8 negatively regulated rice seed germination and seedling growth by interacting with OsCIPK17 with overexpression and gene editing mutant plants as materials combining plant phenotype, physiological indicators and transcriptome sequencing. This process is likely mediated by OsPP2C77, which is a member of the ABA signaling pathway. In addition, OsCBL mediated the targeting of OsNAC77 and OsJAMYB by OsCIPK17, thus conferring resistance to high temperatures and pathogens in rice. Our work reveals a unique signaling pathway, wherein OsCBL8 interacts with OsCIPK17 and provides rice with multiple resistance while also regulating seedling growth.