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 plants can also send sRNAs into pathogens, mainly using extracellular vesicles, mostly exosomes, to silence fungal virulence genes as part of its immune responses (Cai et al., Science 2018). We identified a group of RNA binding proteins that contribute to the selective sRNA loading into extracellular vesicles (He et al., Nature Plants, 2021). Furthermore, we recently demonstrate that B. cinerea also utilizes extracellular vesicles to secrete sRNAs, which are then enter plant cells through clathrin-mediated endocytosis (He et al., Nature Communications, 2023). Thus, extracellular vesicles play an important role in cross-kingdom RNA trafficking between plants and fungal pathogens.

In addition, we discovered that environmental RNAi is present in many fungal pathogens, which can take up RNAs from the environment efficiently (Wang et al,, Nature Plants, 2016; Qiao et al., Plant Biotechnology Journal 2021). Applying small RNAs or double-stranded RNAs that target fungal virulence-related genes on plants can effectively inhibit fungal diseases. Innovative pathogen gene-targeting RNA-based antifungal solutions using nanotechnologies represent a new generation of fungicides that are durable and eco-friendly (Qiao et al., Plant Biotechnology Journal, 2023; Niño-Sánchez et al., Journal of Integrative Plant Biology 2023).