Effects of the entomopathogenic fungus Clonostachys rosea on mortality rates and gene expression profiles in Diaphorina citri adults.

Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a serious pest of citrus. The insect also transmits Candidatus Liberibacter asiaticus, the pathogen of a devastating citrus disease called Huanglongbing. Clonostachys rosea is a versatile fungus that possesses nematicidal and insecticidal activities. The effect of C. rosea against D. citri remains unclear. Here we examined the pathogenicity of C. rosea against D. citri adults. A mortality rate of 46.67% was observed in adults treated with 1 × 108 conidia/mL spore suspension. Comparative transcriptomic analyses identified 259 differentially-expressed genes (DEGs) between controls and samples treated with fungi. Among the DEGs, 183 were up-regulated and 76 down-regulated. Genes with altered expression included those involved in immunity, apoptosis and cuticle formation. Our preliminary observation indicated that C. rosea is virulent against ACP adults and has the potential as a biological control agent for ACP management in the field.