Hosted by: Dr. John Shanklin

Small RNAs (sRNAs) are short non-coding RNAs that mediate gene silencing in a sequence-specific manner. We discovered that some sRNAs from eukaryotic pathogens, such as Botrytis cinerea, can be transported into host plant cells and suppress host immunity genes for successful infection (Weiberg et al., Science 2013). We further demonstrated that such cross-kingdom RNAi is bi-directional. Plants can also send sRNAs into pathogens using extracellular vesicles to silence fungal virulence genes as part of its immune responses (Cai et al., Science 2018). We found that plants have multiple classes of extracellular vesicles, and exosome is the major class responsible for sRNA delivery. Furthermore, we also discovered that many fungal pathogens can take up double-stranded RNAs (dsRNAs) and sRNAs from the environment. Applying sRNAs or dsRNAs that target Botrytis Dicer genes on the surface of fruits, vegetables and flowers significantly inhibits grey mold disease (Wang et al,, Nature Plants, 2016). Such pathogen gene-targeting RNAs represent a new generation of fungicides that are durable and eco-friendly.