SUMMARY
Verticillium wilt, caused by soil-borne fungi of the genus Verticillium, is an economically important disease that affects a wide range of host plants. Unfortunately, host resistance against Verticillium wilts is not available for many plant species, and the disease is notoriously difficult to combat. Host-induced gene silencing (HIGS) is an RNA interference (RNAi) based process in which small RNAs are produced by the host plant to target parasite transcripts. HIGS has emerged as a promising strategy for improving plant resistance against pathogens by silencing genes that are essential for these pathogens. Here, we assessed whether HIGS can be utilized to suppress Verticillium wilt disease by silencing previously identified virulence genes of V. dahliae through the host plants tomato and Arabidopsis. In transient assays, tomato plants were agroinfiltrated with Tobacco rattle virus (TRV) constructs to target V. dahliae transcripts. Subsequent V. dahliae inoculation revealed suppression of Verticillium wilt disease in some, but not all, cases. Next, expression of RNAi constructs targeting V. dahliae transcripts was pursued in stable transgenic Arabidopsis thaliana plants. Also in this host, V. dahliae inoculation revealed reduced Verticillium wilt disease in some cases. Thus, our study suggests that, depending on the target gene chosen, HIGS against V. dahliae is operational in tomato and A. thaliana plants and may act as a plant protection approach that may be used in Verticillium wilt-susceptible crops.
