Exogenous dsRNAs against chitin synthase and glucan synthase genes suppress the virulence of the pathogenic fungus Botrytis cinerea

Botrytis cinerea, the causative agent of the gray mold disease, causes crop failures of many economically important crops worldwide and its control is usually difficult. This study aims to evaluate the effectiveness of RNA interference (RNAi)-based control strategy to suppress the growth of B. cinerea, through exogenous application of double-strand RNA (dsRNA) targeting single and multiple genes encoding crucial enzymes for the fungal cell wall development. The dsRNA molecules were designed to target three single chitin synthase (BcCHSI, BcCHSIIIa, BcCHSVI) and two glucan synthase (alpha-1, 3-glucan synthase (Bcags), β-1, 3-glucan synthase (Bcbgs)), genes. Furthermore, two dsRNA chimeras targeting multiple Chitin synthase (BcCHSI/IIIa/VI) and Glucan synthase genes (Bcags/bgs) have been produced to inhibit Botrytis infection. Here we show that the dsRNAs treatments strongly affect the virulence of the fungus and result in the downregulation of BcCHSI, BcCHSIIIa, BcCHSVI, Bcags, and Bcbgs genes. Overall, our data indicate that exogenous application of dsRNAs can compromise the virulence of B. cinerea and that RNAi-based strategy targeting genes important for B. cinerea cell wall synthesis may provide an effective means to halt the growth of B. cinerea and consequently limit the infection.