Generation of transcriptome profiling and gene functional analysis in Gossypium hirsutum upon Verticillium dahliae infection

Verticillium wilt caused by the soil-borne fungus Verticillium dahliae, is a devastating disease in cotton. To get more candidate genes related to wilt resistance, a normalized, full-length cDNA library was used to generate the transcriptome profile from a wilt-resistant Gossypium hirsutum variety (Zhongzhimian KV3) upon V. dahliae strain V991 infection. Total 3486 high-quality ESTs were focused from randomly selected 4000 clones, which included 3065 singletons and 421 contigs. To categorize these unigenes, they were compared to functional domain databases. Total 106 unigenes were found to be homologous to known defense-related genes. Among them, PR genes were the major group. Furthermore, knockdown of GhWRKY22, GhWRKY33, GhChitinase, GhCML, and GhDirigent resulted in increased susceptibility of resistant cotton to V. dahliae infection. The results of transcriptome profiles and virus induced gene silencing (VIGS) analysis laid a good foundation for further investigation of cotton resistance to wilt disease.