GhDRP1 regulates the drought response by directly interacting with GhHT1 in upland cotton

MAPK（mitogen-activated protein kinase）cascade plays important roles in responding to abiotic stresses for plants. In our present study, 23 association loci associated with seven drought-related traits were obtained based on GWAS（Genome-wide association study）method, and 50 differential expressed genes were selected as candidate ones combined with RNA-Seq data, among which one gene had a significant association with plant height trait under drought condition, named GhDRP1(Drought Response Protein1). GhDRP1 encodes a MPK (mitogen protein kinase) and has higher identity with Arabidopsis AtMPK4, then we created the overexpression (OE) and silencing (SI) GhDRP1 cotton materials, and found that OE plants were sensitive to drought stress, but resistant to drought treatment when expression was down-regulated. Yeast-two hybrid experiments found that GhDRP1 directly interacts with GhHT1 (High leaf temperature 1), and GhHT1 interacts with GhOST1 (Stomatal opening factor 1) which is a key factor regulating stomatal conductance, indicating that GhDRP1 plays key roles during cotton adaptation to drought stress. This study will broaden the knowledge of molecular mechanisms of cotton drought stress response, especially the theoretical basis for MAPK cascade regulating drought resistance in cotton, simultaneously providing important bridge parents for cotton drought resistance breeding.