GhWRKY46 from upland cotton positively regulates the drought and salt stress responses in plant

Abstract

Cotton (Upland Cotton) is one of the major fiber crops in the world. Drought and salinity, as abiotic stress factors, dramatically affect the cotton yield, However, the response processes of cotton to drought and salt stress is still not very clear. Previously, the gene GhWRKY46, encoding WRKY transcription factor protein, was identified to possibly be associated with drought and salt pressure. In present study, the function of GhWRKY46 has been investigated in Arabidopsis and cotton. The transcription factor properties of GhWRKY46 were confirmed by its location in the nucleus and transcriptional activation activity in yeast. Overexpression of GhWRKY46 enhanced tolerance to salt and drought in Arabidopsis, conferring higher survival rates, chlorophyll contents, and biomasses in the overexpression lines under drought stress. Additionally, overexpression of GhWRKY46 enhanced the expression of the stress-related genes AtRD22, AtCBL10, and AtCPK3 in the transgenic Arabidopsis. Silencing of GhWRKY46 in cotton by virus-induced gene silencing resulted in higher sensibilities to salt stress and malondialdehyde contents, as well as lower activities of catalase and peroxidase compared with the control; this further confirmed previous results. Our results demonstrated that GhWRKY46 positively regulates the responses to drought and salt stresses, probably by enhancing the expression of stress-related genes.