CaWRKY6-CaERF3 regulate ROS homeostasis to positively modulate salt stress in pepper (Capsicum annuum L.).

key messageCaWRKY6 functions together with CaERF3 to regulate ROS production, thus positively modulating pepper salt stress response. Salt stress significantly inhibits the growth and productivity of plants. Pepper (Capsicum annuum L.), a widely cultivated economic horticultural crop, exhibits high sensitivity to salinity. This study investigates the role of the transcription factor CaWRKY6 in modulating pepper's responses to salt stress. Our findings indicate that CaWRKY6 predominantly localizes at the cell nucleus, and its expression is significantly induced upon salt treatment. The CaWRKY6-silenced pepper plants exhibit heightened sensitivity to salt stress, as evidenced by increased malondialdehyde (MDA) levels and decreased proline content. Additionally, CaWRKY6-silenced pepper plants show elevated levels of reactive oxygen species (ROS). Through a yeast two-hybrid screen, CaERF3 is identified as an interactor of CaWRKY6. Silencing CaERF3 expression induces a similar sensitive salt response and elevated ROS levels as observed in CaWRKY6-silenced plants. Collectively, our results demonstrate that the CaWRKY6-CaERF3 module positively regulates salt stress responses in pepper by modulating ROS homeostasis.