The Cotton Lignin Biosynthetic Gene Regulates Lignification and Phenolic Content and Contributes to Verticillium Wilt Resistance.

Verticillium wilt is a vascular disease causing tremendous damage to cotton production worldwide. However, our knowledge of the mechanisms of cotton resistance or susceptibility to this disease is very limited. In this study, we compared the defense transcriptomes of cotton () cultivars Shidalukang 1 ( resistant, HR) and Junmian 1 ( susceptible, HS) before and after infection, identified hub genes of the network associated with responses to infection, and functionally characterized one of the hub genes involved in biosynthesis of lignin and phenolics. We identified 6,831 differentially expressed genes (DEGs) between the basal transcriptomes of HR and HS; 3,685 and 3,239 of these DEGs were induced in HR and HS, respectively, at different time points after infection. KEGG pathway analysis indicated that DEGs were enriched for genes involved in lignin biosynthesis. In all, 23 hub genes were identified based on a weighted gene coexpression network analysis of the 6,831 DEGs and their expression profiles at different time points after infection. Knockdown of , one of the hub genes related to the lignin biosynthesis pathway, by virus-induced gene silencing, led to a decreased content of flavonoids, lignin, and S monomer but an increased content of G monomer, G/S lignin monomer, caffeic acid, and ferulic acid, and enhanced cotton resistance to . These results suggest that is a key gene modulating the outputs of different branches of the lignin biosynthesis pathway, and provide new insights into cotton resistance to .[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.