Overexpression of the EfMYB124 gene from Erianthus fulvus enhances tolerance to low temperature and drought in Arabidopsis thaliana

Environmental factors such as low temperature and water stress often hinder the normal growth of sugarcane (Saccharum spp.), which threatens the supply of raw materials for sugar and biomass provided by sugarcane, resulting in severe economic development losses. Improving the stress resistance of sugarcane has always been one of the important directions in sugarcane breeding. Erianthus fulvus, a wild relative of sugarcane, exhibits remarkable stress tolerance. Therefore, fully exploring the excellent stress-tolerance genes in E. fulvus can provide important candidate genes for improving the stress resistance of sugarcane in future molecular breeding programs.

The evolutionary characteristics of EfMYB124, a gene induced by low temperature and drought, were analysed. Moreover, the gene was successfully transferred into Arabidopsis thaliana, and the degree of damage, physiological responses, and stress-induced gene expression of the transgenic plants under stress were investigated. EfMYB124 is most closely related to At1R-MYB in group A1, and the members of this group have the potential to function in response to adverse stress. Numerous syntenic genes of EfMYB124 were identified in the sugarcane genome. Under drought and low-temperature treatments, the EfMYB124-transgenic plants exhibited relatively mild external damage. Moreover, the activities or contents of three antioxidant enzymes (CAT, POD, and SOD) and Pro in these plants increased rapidly, while the production of MDA decreased. Further analysis revealed that EfMYB124 could specifically regulate the expression of cold stress-related genes (CBF1, CBF3, COR15a, and COR4) and drought stress-related genes (RD29A, P5CS1, SOD1, and CAT2). Additionally, EfMYB124 represses the basal expression levels of key ABA signaling-related genes, including NCED3, ABI5, ABF2, and RD29B.

In summary, this study has initially confirmed that EfMYB124 plays a positive role in regulating plants’ resistance to drought and low temperatures. These key findings lay a solid foundation for us to further analyze the function of EfMYB and study its upstream and downstream interaction relationships. Meanwhile, they provide the necessary scientific reference for the future application of this gene in the genetic improvement of stress tolerance trait breeding in sugarcane.