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

Abstract

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.

Combined metabolomic and transcriptomic analysis reveals key components of OsCIPK17 overexpression improves drought tolerance in rice

“…Compared with WT plants, OsCIPK17 -Mutant plants showed earlier and more severe drought symptoms with rolled leaves and withered plants, whereas OsCIPK17 -OE plants showed relatively later and milder drought symptoms ( Figure 1A , middle pannel). This is consistent with our previous study ( Gao et al., 2022a ). Two days after re-watering, OsCIPK17 -OE plants showed a higher survival rate, while almost all OsCIPK17 -Mutant plants died ( Figure 1A , lower panel).…”

“…(A) Growth phenotype of 3-week-old transgenic OsCIPK17 -OE, OsCIPK17 -Mutant, and WT plants at different stages of drought stress; bar = 7cm. The upper and middle channels in a have the same results as Gao et al. (2022a) (Published in the International Journal of Molecular Science on 18 October 2022).…”

“…OsCIPK17 is one of the 33 CIPK family members in rice, although its specific functions remain unknown. In a previous study, we identified two OsCBL s upstream of OsCIPK 17 and verified their interaction using Y2H and bimolecular fluorescence complementation (BiFC) assays ( Gao et al., 2022a ). Interestingly, OsCBL s and OsCIPK17 exhibited the same phenotype under drought ( Figure S4A ).…”

“…Further, the RWC ( Figure S4B ) and survival rate ( Figure S4C ) were analyzed and similar pattern to OsCIPK17 were noted. Presumably, OsCBL8 senses the Ca 2+ signal upon exposure to drought and activate OsCIPK17 to respond to stress ( Gao et al., 2022a ). Our previous research also shows that OsCIPK17 also plays an important role in the rice filling process ( Gao et al., 2022b ).…”

“…Therefore, both gene and non-enzymatic chemical cascades may work synergistically to regulate plant drought tolerance. In a previous study, we found OsCIPK17 overexpression improved rice drought tolerance (Gao et al, 2022a). Therefore, we sequenced the transcriptome and metabolome of the wildtype (WT) Nipponbare (NIP) and OsCIPK17-overexpressing lines (OsCIPK17-OE) to identify the key genes and metabolites involved in the regulation of rice drought resistance and clarify the specific regulatory factors.…”