Genome-wide identification of cyclophilin genes in Gossypium hirsutum and functional characterization of a CYP with antifungal activity against Verticillium dahliae.

Cyclophilins (CYPs), belonging to the peptidyl prolyl cis/trans isomerase (PPIase) superfamily, play important roles during plant responses to biotic and abiotic stresses.Here, a total of 79 CYPs were identified in the genome of Gossypium hirsutum. Of which, 65 GhCYPs only contained one cyclophilin type PPIase domain, others 14 GhCYPs contain additional domains. A number of cis-acting elements related to phytohormone signaling were predicated in the upstream of GhCYPs ORF. The expression analysis revealed that GhCYPs were induced in response to cold, hot, salt, PEG and Verticillium dahliae infection. In addition, the functional importance of GhCYP-3 in Verticillium wilt resistance was also presented in this study. GhCYP-3 showed both cytoplasmic and nuclear localization. Overexpression of GhCYP-3 in Arabidopsis significantly improved Verticillium wilt resistance of the plants. Recombinant GhCYP-3 displayed PPIase activity and evident inhibitory effects on V. dahliae in vitro. Moreover, the extracts from GhCYP-3 transgenic Arabidopsis displayed significantly inhibit activity to conidia germinating and hyphal growth of V. dahliae.Our study identified the family members of cotton CYP genes using bioinformatics tools. Differential expression patterns of GhCYPs under various abiotic stress and V. dahliae infection conditions provide a comprehensive understanding of the biological functions of candidate genes. Moreover, GhCYP-3 involved in the resistance of cotton to V. dahliae infection presumably through antifungal activity.