Bermudagrass CdWRKY50 gene negatively regulates plants' response to salt stress

Salinity influences the growth and geographical distribution of plants. Bermudagrass [Cynodon dactylon (L). Pers.] shows relatively strong tolerance to salt, and hence contributes to restoration of saline-alkali land. WRKY proteins have been proven to be widely involved in regulating salt stress response in plants. However, to date, the functions of bermudagrass WRKY genes that are involved in salinity response remain largely unknown. In this study, CdWRKY50 was isolated and analyzed in bermudagrass. The expression of CdWRKY50 was up-regulated by salt, drought, cold, and abscisic acid treatments. Silencing CdWRKY50 via a virus-induced gene silencing method enhanced salt tolerance of bermudagrass. Conversely, transgenic Arabidopsis overexpressing CdWRKY50 lines showed salt-sensitive phenotype compared with wild type. Furthermore, CdWRKY50 can bind to AtDREB2Apromoter and regulate its expression by yeast one-hybrid and dual-luciferase reporter assay, thus regulating its expression. Taken together, our study revealed that CdWRKY50 is a negative regulator mediating plants response to salt stress, which provides scientific foundation for developing salt-tolerant plants through genetic engineering.