Fungal Argonaute proteins act in bidirectional cross-kingdom RNA interference during plant infection

Argonaute (AGO) proteins bind to small RNAs to induce RNA interference (RNAi), a conserved gene regulatory mechanism in animal, plant, and fungal kingdoms. Small RNAs of the fungal plant pathogen Botrytis cinerea were previously shown to translocate into plant cells and bound to the host AGO, which induced cross-kingdom RNAi to promote infection. However, the role of pathogen AGOs during host infection stayed elusive. In this study, we revealed that members of fungal plant pathogen Botrytis cinerea BcAGO family contribute to plant infection and act in bidirectional cross-kingdom RNAi, from fungus to plant and vice versa. Providing these new mechanistic insights of pathogen AGOs promise to improve RNAi-based crop protection strategies.