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 <i>Deinococcus</i> 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 <i>Brassica napus</i> L. (oilseed rape) remains unexamined. In this study, a synthetic stress-resistance module, DICW, was constructed using the <i>Deinococcus</i>-derived genes <i>IrrE</i>, <i>Csp</i>, and <i>WHy</i> and heterologously overexpressed in <i>B. napus</i> 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 <i>B. napus</i> 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 (<i>BnRD29A</i>, <i>BnP5CS</i>, <i>BnKIN1</i>, <i>BnLEA1</i>, <i>BnNHX1</i>, and <i>BnSOS1</i>) and antioxidant enzyme-related genes (<i>BnSOD</i>, <i>BnPOD</i>, and <i>BnCAT</i>) in transgenic lines. In conclusion, the DICW module plays a crucial role in enhancing salt tolerance in <i>B</i>. <i>napus</i> by regulating stress responses and antioxidant mechanisms. This study provides valuable molecular insights into improving the survival and growth of <i>B. napus</i> in saline environments.