Drought and high salinity are key limiting factors for cotton production. Therefore, research is increasingly focused on the underlying stress response mechanisms of cotton. We first identified and cloned a novel gene encoding the 525
amino acids in cotton, namely GhWRKY6. qRT-PCR analysis indicated that GhWRKY6 was induced by NaCl,
PEG 6000 and ABA. Analyses of germination rate and root length indicated that overexpression of GhWRKY6 in Arabidopsis resulted in
hypersensitivity to ABA, NaCl, and
PEG 6000. In contrast, the loss-of-function mutant wrky6 was insensitive and had slightly longer roots than the wild-type did under these treatment conditions. Furthermore, GhWRKY6 overexpression in Arabidopsis modulated
salt- and drought-sensitive phenotypes and stomatal aperture by regulating ABA signaling pathways, and reduced plant tolerance to abiotic stress through
reactive oxygen species (ROS) enrichment, reduced
proline content, and increased
electrolytes and
malondialdehyde (MDA). The expression levels of a series of ABA-,
salt- and drought-related marker genes were altered in overexpression seedlings. Virus-induced gene silencing (VIGS) technology revealed that down-regulation of GhWRKY6 increased salt tolerance in cotton. These results demonstrate that GhWRKY6 is a negative regulator of plant responses to abiotic stress via the ABA signaling pathway.