Increased virulence in the locust-specific fungal pathogen Metarhizium acridum expressing dsRNAs targeting the host F1F0-ATPase subunit genes

BACKGROUND Metarhizium acridum is a host-specific fungal pathogen with great potential for locust control. However, the slow killing action of M. acridum has impeded its widespread application. To enhance fungal virulence, we constructed transgenic M. acridum strains that express double-stranded (ds)RNAs targeting the genes of the F1F0-ATP synthase alpha and beta subunits in Locusta migratoria. RESULTS The two host genes were transcriptionally suppressed in L. migratoria nymphs (instar V) infected by RNA interference (RNAi) strains targeting one or two subunit genes of the host ATP synthase, followed by reduced ATPase activity and ATP synthesis. Consequently, the RNAi strain targeting both subunit genes displayed high virulence that was 3.7-fold that in the wild-type strain. CONCLUSION Our results demonstrate that dsRNA expression in M. acridum can cause host RNA silencing during infection and greatly enhances the fungal virulence through interference with critical host genes, highlighting a new strategy for augmentation of fungal virulence against insect pests. (c) 2018 Society of Chemical Industry