The OsEBF1-OsEIL5-OsPP91 module regulates rice heat tolerance via ubiquitination and transcriptional activation

Understanding the regulatory mechanisms underlying the plant heat stress response is important for developing climate-resilient crops, including rice (Oryza sativa). Here, we report that OsEIL5, one member of the ETHYLENE INSENSITIVE3-LIKE family, positively regulates rice heat tolerance at the seedling and reproductive stages. OsEIL5 directly binds to the promoter of OsPP91 (encoding one type 2C protein phosphatase) and activates its expression. OsPP91 is required for rice thermotolerance, and overexpressing OsPP91 in oseil5-1 partially rescues its heat sensitivity. The F box protein OsEBF1 interacts with OsEIL5 and degrades it through the ubiquitination pathway, resulting in the reduction of OsPP91 expression and ultimately weakening rice heat tolerance. Knocking out OsEIL5 in the EBF1R13 line partially reduces its extremely high heat tolerance. Taken together, our work uncovers a mechanism that finely regulates rice thermotolerance through the OsEBF1-OsEIL5-OsPP91 module at the posttranslational and transcriptional levels.