Genome-wide association study identifies variants of GhSAD1 conferring cold tolerance in cotton

Cold stress is a major environmental factor affecting plant growth and development. Although some plants have developed resistance to cold stress, the molecular mechanism underlying it is poorly understood. Here, we identified cold tolerance gene in cotton ( Gossypium hirsutum L.) using genome-wide association study (GWAS) with 200 cotton accessions collected from different regions, and identified variations of a short chain alcohol dehydrogenase gene GhSAD1 that response to cold stress. The virus induced gene silencing (VIGS) and Arabidopsis overexpression experiments showed that GhSAD1 roles in cold-stress response. GhSAD1 HapB introduction considerably increased cold tolerance in Arabidopsis transgenic plants, whereas GhSAD1 HapA plants exhibited cold-sensitive phenotype. GhSAD1 HapB silencing plants exhibited a decrease of abscisic acid (ABA) content and overexpression GhSAD1 HapB in Arabidopsis increased ABA content. Additionally, we found that GhSAD1 HapB regulated cold stress responses through the activity of c-repeat binding factor, which binds to the promoter region of the gene and regulates ABA signalling pathway under cold conditions. Overexpression of GhSAD1 HapB induced cold-regulated ( COR ) genes expression and improved anti-cold metabolites under cold stress. Collectively, the findings of the study contribute to our understanding of the underlying mechanism of GhSAD1 in cold-stress response in cotton. Moreover, GhSAD1 could serve as candidate gene in improving crop stress