OsDREB1B regulates cold and salt stress responses in rice (Oryza sativa L.).

Abstract

Dehydration-responsive element-binding (DREB) transcription factors play central roles in plant adaptation to abiotic stresses; however, the stress-specific functions and regulatory mechanisms of individual DREB members in rice remain incompletely understood. Here, we conducted a systematic analysis of the rice DREB gene family and identified OsDREB1B as a stress-responsive transcription factor involved in cold and salt stress responses. OsDREB1B contains a conserved AP2 DNA-binding domain and is transcriptionally induced by cold, salt, and PEG-induced osmotic stress. Subcellular localization assays revealed that OsDREB1B displays stress-dependent localization, with dual localization in the nucleus and plasma membrane under normal conditions and predominant nuclear accumulation under cold stress. Functional analyses using two independent CRISPR/Cas9-generated loss-of-function alleles demonstrated that disruption of OsDREB1B increased sensitivity to cold and salt stresses, as reflected by reduced survival rate, increased H2O2 and O2•- accumulation, impaired antioxidant enzyme activities, and increased membrane damage. In contrast, osmotic stress was largely unaffected despite transcriptional induction of OsDREB1B under PEG-induced osmotic stress. Collectively, these results demonstrate that OsDREB1B positively contributes to cold and salt stress responses in rice and reveal a cold-associated change in its subcellular distribution.