Overexpression of okra transcription factor AeWRKY31 enhanced cold resistance of Arabidopsis by promoting ABA biosynthesis and inhibiting ROS generation

Abstract

The changing climate leads to frequent low-temperature events, resulting in lower crop yields worldwide. Plant growth and development are regulated by WRKYs, as well as a variety of defense responses, including salt, drought, and extreme temperature stress. Here, a transcription factor AeWRKY31 was obtained from Abelmoschus esculentus and overexpressed in Arabidopsis thaliana. Molecular localization and self-transactivation assays revealed AeWRKY31 to be a nuclear localized protein with a self-transactivation property. Subsequently, AeWRKY31 activated the expression of AtABA1, AtABA2, and AtNCED6, and promoted endogenous ABA accumulation, which induced stomata closure of AeWRKY31 overexpression Arabidopsis. Histochemical staining and ROS content determination demonstrated that AeWRKY31 expression inhibited the accumulation of H2O2 and O2- and decrease electrolyte leakage of Arabidopsis. Meanwhile, relative expression levels of cold-response genes were upregulated in AeWRKY31 overexpression lines compared to WT. Finally, AeWRKY31 overexpression Arabidopsis lines showed enhanced cold tolerance in vivo and in vitro experiments. Our findings will benefit molecular breeding and cold resistant mechanism investigation of okra.