Overexpression and silencing of the cotton GhABA2 gene reveal its role in salt stress tolerance

ABA2 encodes a short-chain dehydrogenase/reductase involved in the regulation of abscisic acid (ABA) biosynthesis and plays a crucial role in plant responses to salt stress. To explore the function of GhABA2 in cotton salt tolerance, we conducted bioinformatic analyses, gene overexpression, and virus-induced gene silencing (VIGS) experiments. Bioinformatic examination revealed that the promoter region of the GhABA2 gene contains multiple cis -acting elements, including those responsive to ABA, light, and various stress signals. Overexpression of GhABA2 in Arabidopsis resulted in significantly increased seed germination rate, root length, leaf relative water content (RWC), catalase (CAT) activity, peroxidase (POD) activity, and proline (Pro) content under salt stress conditions, while malondialdehyde (MDA) content was markedly reduced. Conversely, silencing GhABA2 gene in cotton via virus-induced gene silencing (VIGS) led to significant decreases in ABA content, RWC, superoxide dismutase (SOD) activity, POD activity, and Pro content, along with a significant increase in MDA content. These findings provide important insights into the mechanism of GhABA2 in mediating cotton salt stress response and highlight its potential as a genetic target for breeding of salt-tolerant cotton varieties.