dsRNA as a novel tool to fight Verticillium diseases - from basics to future application

With a growing knowledge about the inherent activities of double-stranded (ds)RNA, it could become an effective tool in targeting crucial virulence genes in fungi and other plant pathogens, which in turn would give an edge for plants in the continuous fight against invading pathogens. The non-GMO dsRNA application – spray-induced gene silencing (SIGS) – faces many challenges, including the various biological barriers on the plant side, and many environmental factors that could degrade dsRNA in field settings. To tackle such challenges, chemical formulations are being developed for more efficient and sustained delivery of selected dsRNAs via SIGS. In this study, we developed a pathosystem with the model dicot plant Arabidopsis thaliana and the ascomycete Verticillium longisporum, a root pathogen that targets Brassica napus and causes considerable economic losses wordwide. We present data on dsRNA uptake in liquid fungal cultures and down-regulation of target genes in V. longisporum, as a function of the length of dsRNA molecules and delivery methods. The ability to limit fungal virulence was studied in a hydroponic system, which allows for better access to root tissues and fungal biomass quantification after treatment with non-formulated vs. formulated dsRNA. The study aims to provide insights into the capability of dsRNA application in limiting fungal diseases, by means of RNA interference mechanism present in the vast majority of eukaryotic cells, and to provide a reliable system for evaluating uptake, processing and efficacy of dsRNA as a novel natural compound with disease limiting activity. Finanzierung: SusCrop - ERA-NET FACCE-JPI, DFG