Expression Profiles Reveal the Function of Upland Cotton DUF642 Gene Family in Stress Tolerance

[Objective] DUF642 (Domain of unknown function 642 genes), an unknown functional gene family, plays an important role in plant stress response. The aim of this study is to analyze its function in cotton stress response. [Method] The members of DUF642 gene family in cotton were systematically identified base on the information from Gossypium hirsutum genome. The gene structure, physiochemical properties, subcellular localization, phylogenetic evolution and promoters of DUF642 were analyzed by bioinformatics. The expression patterns of DUF642 genes in different tissues and under various stresses, including cold, hot, drought, salt and Verticillium dahliae infection, were analyzed by transcriptome data and real-time quantitative polymerase chain reaction (RT-qPCR). [Result] The results showed that 23 DUF642 genes in G. hirsutum distributed on 14 chromosomes and one scaffold. Most of GhDUF642 proteins were predicated to be in the plasma membrane and contain 1―2 conserved DUF642 domains. GhDUF642 genes were divided into four subgroups and highly conservative in evolution. GhDUF642 genes have a wide range of tissue expression types, most of which are highly expressed in roots and leaves. Combining promoter analysis and expression analysis, it was speculated that GhDUF642-09 participated in cotton resistance to salt stress, GhDUF642-08 and GhDUF642-19 were involved into the interaction between cotton and V. dahliae, and GhDUF642-02, GhDUF642-14 and GhDUF642-17 were related to cotton growth and stress tolerance. [Conclusion] These results could provide reference for further study on the function of DUF642 genes and the molecular mechanism for stress resistance in cotton.