CaMYB30 positively activate the expression of CaWRKY29 and regulates salt stress via modulating ROS homeostasis in pepper (Capsicum annuum L.).

Abstract

Pepper (Capsicum annuum L.) exhibits a pronounced sensitivity to salt stress, making it crucial to investigate the genetic mechanisms that confer salt tolerance. The MYB transcription factor family is pivotal in mediating plant growth and responses to environmental stresses. However, the specific involvement of MYB in pepper responses to salinity remain largely uncharacterized. In this work, we identified CaMYB30 as a crucial regulator of pepper's response to salt stress. Additionally, we discovered that CaMYB30 can directly bind to the CaWRKY29 gene promoters and positively activate its expression. Silencing either CaMYB30 or CaWRKY29 resulted in heightened sensitivity to salinity stress, as evidenced by increased electrolyte leakage and elevated Na+/K+ ratios. Furthermore, we demonstrated that the CaMYB30-CaWRKY29 module played a role in regulating reactive oxygen species (ROS) homeostasis by modulating the activities of peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) enzymes. Collectively, our findings provided essential insights into the regulatory role of the CaMYB30-CaWRKY29 module in the context of pepper salt stress, establishing a foundation for subsequent functional validation and genetic engineering applications.