FvWRKY75 Positively Regulates to Enhance Salt Stress Tolerance.

Strawberry ( Duch.) is an important fruit worldwide whose growth, development, and productivity are threatened by salinity. The WRKY transcription factors (TFs) were reported to play an important role in regulating abiotic stresses response. However, research on their roles to regulate salt stress tolerance in strawberry remains limited. In current study, the gene was isolated and characterized from the Ruegen strawberry, and induced by various stress treatment. The results showed that the FvWRKY75 transcription factor was a transcriptional activator and localized in the nucleus. Phenotypic and physiological analysis revealed that ectopic expression of in improved salt tolerance by enhancing the antioxidant system activities, modulating ROS scavenging and upregulating stress-related genes. Y1H and dual luciferase assays revealed that FvWRKY75 can directly bind to the promoter of the gene by recognizing the W-box element. Compared with the WT, ectopic expression of gene in enhanced salt tolerance characterized by the reduced ROS accumulation, higher chlorophyll content, lower MDA content, and enhanced SOD and POD activity. Herein, the FvWRKY75 gene acted as a positive regulator in salt stress resistance, at least in part, via the WRKY-CRK network to regulate the antioxidant enzyme defense system and stress-related genes to regulate salt stress tolerance in strawberry.