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.
Therefore, the aim of this study was to identify genes conferring cold
resistance in cotton. 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. A
variant of the gene was also identified. The results of the study showed
that GhSAD1HapB improved cold-stress resistance
in cotton by increasing abscisic aldehyde (ABAld) and amino acid
contents under chilling stress conditions.
GhSAD1HapB introduction considerably increased
chilling tolerance in Arabidopsis transgenic plants, whereas
GhSAD1HapA plants exhibited chilling-sensitive
phenotype. Additionally, we found that
GhSAD1HapB regulated chilling stress responses
in cotton through the activity of c-repeat binding factor, which binds
to the promoter region of the gene and regulates the ABA signalling
pathway under chilling conditions. Overexpression of
GhSAD1HapB induced COR genes expression
and improved metabolic profile 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.