Improved Salt Tolerance in Brassica napus L. Overexpressing a Synthetic Deinocuccus Stress-Resistant Module DICW

Salt stress adversely impacts plant physiology by causing ionic, osmotic, and oxidative stress, ultimately hindering growth and yield. The genus Deinococcus contains unique stress resistance genes, and previous studies have shown that proteins such as IrrE, Csp, and WHy enhance stress tolerance in plants and microbial cells. However, their role in Brassica napus L. (oilseed rape) remains unexamined. In this study, a synthetic stress-resistance module, DICW, was constructed using the Deinococcus-derived genes IrrE, Csp, and WHy and heterologously overexpressed in B. napus to assess its impact on salt tolerance. The results demonstrated that the DICW module significantly improved seed germination and seedling growth under salt stress. Transgenic B. napus plants exhibited reduced membrane damage, higher leaf relative water content, enhanced accumulation of osmoregulatory substances, and elevated antioxidant enzyme activity compared to wild-type plants. Additionally, qRT-PCR analysis revealed the upregulation of stress-related genes (BnRD29A, BnP5CS, BnKIN1, BnLEA1, BnNHX1, and BnSOS1) and antioxidant enzyme-related genes (BnSOD, BnPOD, and BnCAT) in transgenic lines. In conclusion, the DICW module plays a crucial role in enhancing salt tolerance in B. napus by regulating stress responses and antioxidant mechanisms. This study provides valuable molecular insights into improving the survival and growth of B. napus in saline environments.