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

Abstract

Abstract Cold stress is a major environmental factor affecting plant growth and development. Although some plants have developed resistance to cold stress, the molecular mechanisms underlying this process are poorly understood. Using genome-wide association mapping (GWAS) with 200 cotton accessions collected from different regions, we identified variations in the short chain alcohol dehydrogenase gene, GhSAD1, that responds to cold stress. Virus-induced gene silencing (VIGS) and overexpression in Arabidopsis revealed that GhSAD1 fulfils important roles in cold-stress responses. Ectopic expression of GhSAD1HapB in Arabidopsis increased cold tolerance. Silencing of GhSAD1HapB resulted in a decrease in abscisic acid (ABA) content. Conversely, overexpression of GhSAD1HapB increased ABA contents. GhSAD1HapB regulates cold stress responses in cotton through modulation of C-repeat binding factor activity, which regulates ABA signalling. GhSAD1HapB induces the expression of COLD-REGULATED (COR) genes and increases the levels of metabolites associated with cold stress tolerance. Overexpression of GhSAD1HapB partially complements the phenotype of the aba2-1 mutant. Collectively, the findings increase our understanding of the mechanisms underlying GhSAD1-mediated cold-stress responses in cotton.