AnWRKY29 from the desert xerophytic evergreen Ammopiptanthus nanus improves drought tolerance through osmoregulation in transgenic plants

Abstract

As a significant transcription factor family in plants, WRKYs have a crucial role in responding to different adverse environments. They have been repeatedly demonstrated to contribute to drought resistance. However, no systematic exploration of the WRKY family has been reported in the evergreen shrub Ammopiptanthus nanus under drought conditions. Here, we showed that AnWRKY29 expression is strongly induced under drought stress. AnWRKY29 belongs to the group IIe of WRKY gene family. To characterize the function of AnWRKY29, we generated transgenic plants overexpressing this gene in Arabidopsis thaliana. We determined that AnWRKY29 overexpression of mainly improves the drought resistance of transgenic plants to water stress by reducing water loss, preventing electrolyte leakage, and increasing the absorption of inorganic ions. In addition, the AnWRKY29 transgenic plants synthesized more trehalose under water stress. The overexpression of AnWRKY29 also enhanced the antioxidant and osmoregulation capacity of transgenic plants by increasing the activities of catalase, peroxidase and superoxide dismutase, thus increasing the scavenging of reactive oxygen species and propylene glycol synthesis aldehyde oxidase. In summary, our study shows that AnWRKY29 plays an important role in the drought tolerance pathway in plants.