GhWRKY70-GhXDH1 module enhances drought tolerance in cotton by maintaining ROS homeostasis

WRKY transcription factors are key regulators of plant stress responses. However, functional characterization of cotton WRKY genes under drought stress has largely relied on omics-based predictions or heterologous expression, with few studies employing stable cotton transformants for direct validation. Here, we identified a drought-responsive gene, GhWRKY70, which is induced by simulated drought (PEG 6000). Overexpression of GhWRKY70 in cotton displayed enhanced drought tolerance, and its mutant ghwrky70 resulted in reduced drought tolerance. RNA-sequencing combined with physiological analyses showed that numerous differentially expressed genes (DEGs) between GhWRKY70 overexpression lines (OE) and wild type (WT) were involved in oxidative stress-related pathways. Under drought stress, and the activities of antioxidant enzymes and total antioxidant capacity (T-AOC) were significantly higher in GhWRKY70 OE lines compared to WT. We further identified GhXDH1, a xanthine dehydrogenase-like gene, as a direct downstream target of GhWRKY70. Silencing GhXDH1 through VIGS decreased drought tolerance, indicating its positive role in drought tolerance. Together, these findings reveal a GhWRKY70-GhXDH1 regulatory module that enhances drought resistance in cotton and offers a mechanistic basis for developing drought-tolerant cultivars.