Proteomic approaches of Trichoderma hamatum to control Ralstonia solanacearum causing pepper bacterial wilt

Abstract

Hunan province has the largest pepper cultivation and highest pepper consumption in China. In recent years, peppers (Capsicum frutescens l.) cultivated in Hunan province have been infected by Ralstonia solanacearum, causing bacterial wilt thus inducing vast economic losses. Twenty-two strains of Trichoderma were isolated from soil samples near the pepper cultivation area in LiLing, Hunan province, PR China. Phylogenetic analysis based on the ITS region of the isolated strains detected three species including Trichoderma hamatum, T. asperellum, and T. virens. An antimicrobial test showed that T. hamatum strain yyH13 had the greatest antimicrobial activity against the bacterial wilt pathogen and that proteins in the liquid metabolites played a major role in this activity. A 1D-shotgun proteomics approach, in conjunction with LC-MS/MS, identified 125 different secreted proteins. Most of the antimicrobial proteins contain several specific chitinases that play an important role as hydrolytic enzymes during cell wall degradation.