Evolution, expression and functional analysis of cultivated allotetraploid cotton DIR genes

Abstract Background Dirigent (DIR) proteins mediate regioselectivity and stereoselectivity during lignan biosynthesis are also involved in lignin, gossypol pterocarpan biosynthesis. This gene family plays a vital role enhancing stress resistance secondary cell-wall development, but systematical understanding is lacking cotton. Results In this study, 107 GbDIRs GhDIRs were identified Gossypium barbadense hirsutum , respectively. Most of these genes have classical structure without intron encode containing signal peptide. Phylogenetic analysis showed that cotton DIR classified into four distinct subfamilies (a, b/d, e, f). Of groups, DIR-a DIR-e evolutionarily conserved, segmental tandem duplications contributed equally to their formation. contrast, DIR-b/d mainly expanded by recent duplications, accompanying with number clusters. With the rapid evolution, DIR-b/d-III was -specific clade atropselective synthesis gossypol. RNA-seq data highlighted GhDIR s response Verticillium dahliae infection suggested could confer wilt resistance. We candidate related fiber development G. revealed differential expression. To further determine involvement we overexpressed length-related GbDIR78 Arabidopsis validated its function trichomes hypocotyls. Conclusions These findings contribute novel insights towards evolution provide valuable information for roles as well responses.