Heterologous expression of the TaCBF2 gene improves cold resistance in Begonia semperflorens

Low temperature greatly limits Begonia semperflorens growth and production. Enhancing the low-temperature tolerance of B. semperflorens is essential. The overexpression of C-repeat/DRE binding factors (CBF/DERB) can confer plant tolerance to cold stress. In this study, we used genetic engineering to obtain TaCBF2-overexpressing transgenic B. semperflorens lines. Compared with the control plants, the transgenic plants presented increased tolerance to 4 °C cold stress, increased survival rates, and lower semilethal temperature values. In addition, greater antioxidant enzyme activity and osmoregulatory material content and lower ROS accumulation were detected in the TaCBF2-overexpressing lines. Furthermore, the expression of the cold-responsive genes BsCOR27, BsCOR413, BsKIN, BsLTI and BsRD was significantly upregulated in the TaCBF2-overexpressing lines. Together, these results suggest that TaCBF2 can increase the vitality of green flowering crabapple by regulating the expression of ROS accumulation and cold-response genes, allowing transgenic plants to accumulate lower levels of ROS and reducing the degree of cellular damage caused by ROS. These findings indicate that the TaCBF2 gene can be used for genetic engineering and breeding and for the cultivation of B. semperflorens resistant to cold stress.