Genome-wide Identification and Bioinformatics Analysis of Cotton KCR Gene Family

3-ketoacyl-CoA reductase (KCR) is a key enzyme gene in the biosynthesis pathway of ultra-long chain monounsaturated fatty acids. Combining the sequence of KCR protein in Arabidopsis thaliana, we conducted a whole-genome identification and systematic evolutionary study of the KCR gene in cotton, focusing on Gossypium. arboreum, Gossypium. raimondii, Gossypium. barbadense, Gossypium. hirsutum. We analyzed the expression pattern of the KCR gene in high oil and low oil materials using transcriptome data and quantitative real-time polymerase chain reaction (qRT-PCR). Four KCR genes were identified in Gossypium. arboreum, four in Ramond cotton, eight in Sea Gossypium. barbadense, and eight in Gossypium. hirsutum. Systematic evolutionary analysis divided the cotton KCR gene family members into three branches, and all branches had similar conserved motifs. Some promoter regions of Gossypium. hirsutum KCR genes contained light response and drought regulation elements, suggesting that the Gossypium. hirsutum KCR gene family may play a role in stress response. Four genes were identified that showed significant expression differences in the 15 DPA of high oil and low oil seed development, indicating that GhKCR gene family members may be related to lipid synthesis metabolism. The evolutionary relationship and related functions of KCR gene family members in cotton were analyzed and predicted, which provided a preliminary theoretical basis for the study of KCR gene function in cotton.