Identification of sugar transporter genes and their roles in the pathogenicity of on cotton.

INTRODUCTION

Verticillium wilt (VW) caused by is a soil-borne vascular fungal disease that severely affects cotton yield and fiber quality. Sugar metabolism plays an important role in the growth and pathogenicity of . However, limited information is known about the sugar transporter genes and their roles in the growth and pathogenicity of .

METHOD

In this study, genome-wide identification of sugar transporter genes in was conducted and the expression profiles of these genes in response to root exudates from cotton varieties susceptible or resistant to were investigated based on RNA-seq data. Tobacco Rattle Virus-based host-induced gene silencing (TRV-based HIGS) and artificial small interfering RNAs (asiRNAs) were applied to investigate the function of candidate genes involved in the growth and pathogenic process of .

RESULTS

A total of 65 putative sugar transporter genes were identified and clustered into 8 Clades. Of the 65 sugar transporter genes, 9 were found to be induced only by root exudates from the susceptible variety, including and that were selected for further functional study. Silencing of or in host plants by TRV-based HIGS reduced fungal biomass and enhanced cotton resistance against . Additionally, silencing of and by feeding asiRNAs targeting (asiR815 or asiR1436) and (asiR201 or asiR1238) inhibited fungal growth, exhibiting significant reduction in hyphae and colony diameter, with a more significant effect observed for the asiRNAs targeting . The inhibitory effect of asiRNAs on the growth of was enhanced with the increasing concentration of asiRNAs. Silencing of by feeding asiR815+asiR1436 significantly decreased the pathogenicity of .

DISCUSSION

The results suggest that and are sugar transporter genes required for growth and pathogenicity of and that asiRNA is a valuable tool for functional characterization of genes.