WRKY transcription factors play crucial roles in plant growth, development, and responses to abiotic and biotic stresses. Arachis duranensis, a diploid progenitor of cultivated peanuts (Arachis hypogaea), serves as a valuable genetic resource for improving stress tolerance in peanut breeding. In this study, heterologous expression of AdWRKY40 in Saccharomyces cerevisiae and Arabidopsis thaliana enhanced drought tolerance. Overexpression of AdWRKY40 in A. thaliana also led to reduced leaf area. Mechanistically, AdWRKY40 directly repressed polygalacturonase 1 β 3 (AdPGL3) expression. Overexpression of AdPGL3 in yeast and A. thaliana increased drought sensitivity. Further analyses revealed that AdWRKY40 enhances drought tolerance by modulating the reactive oxygen species (ROS) pathway independently of the abscisic acid pathway. Low-temperature treatment suppressed AdWRKY40 expression, reversed the small-leaf phenotype, and diminished drought tolerance in transgenic lines. Collectively, our findings establish AdWRKY40 as a negative regulator of AdPGL3 that enhances drought tolerance by modulating the ROS pathway and temperature-dependent signaling.
Li et al. (Mon,) studied this question.