OsGSK1 interacts with OsbZIP72 to regulate salt response in rice

Abstract

Soil salinity remains a continuing threat to agriculture worldwide, greatly affecting seedling development and reducing crop yield. Thus, the cultivation of salt-resistant crops on salinized land is an excellent strategy to ensure food security. The rice GSK3-like protein kinase, OsGSK1, is known to play a role in the response to various abiotic stressors; however, the underlying molecular mechanism of this response remains unclear. Here, we aimed to elucidate the mechanism by which OsGSK1 regulates the salt stress response. We found that OsGSK1 interacts with OsbZIP72 to negatively regulate salt stress tolerance in rice plants. OsGSK1 is specifically induced by cold, salt stress, and abscisic acid (ABA) treatment. OsGSK1 was found to be localized in the nucleus and cytoplasm, where it physically interacts with OsbZIP72 – a positive regulator of the rice salt stress response. OsbZIP72 directly binds to the ABA response element in the OsNHX1 promoter to regulate its expression under salt stress, whereas OsGSK1 interacts with OsbZIP72 to repress OsNHX1 expression. The knockout of OsGSK1 increased salt tolerance without affecting the main agronomic traits of the mutant plants. Therefore, OsGSK1 could be used to maintain rice yield in salinized soil.