A4 The role of fungal Argonautes and other types of RNA-binding proteins in Botrytis-plant cross-kingdom RNAi
Dr. Arne Weiberg
Ludwigs-Maximilians-Universität München (LMU)
Grosshaderner Str. 2-4
Tel.: +49 (0)89 / 2180-74731
Botrytis cinerea is an aggressive fungal plant pathogen. For successful infection, B. cinerea secretes cross-kingdom small RNAs (sRNA) into plant cells that hijack the plant Argonaute/RNA-induced silencing complex (AGO/RISC) to suppress important host defence genes. This virulence strategy based on a fascinating mechanism that is called cross-kingdom RNA interference (ckRNAi). The Arabidopsis thaliana host plant of Botrytis transfers ck-sRNAs into the fungus to suppress pathogen genes, too. The role of the four Botrytis AGOs in this bidirectional cross-kingdom RNAi is not explored. On the one hand, plant hosts might have evolved ck-sRNAs that can load into Botrytis AGOs to achieve pathogen gene silencing. On the other hand, Botrytis AGOs might be important players not only in fungal endogenous RNAi, but also in small RNA sorting into secretory pathways for extracellular RNA transport. Extracellular vesicles (EVs) are produced by plants and Botrytis, and it has been uncovered that plant and Botrytis EVs contain ck-sRNAs. Thus, EVs are proposed to play pivotal roles in fungal-plant interactions by transporting small RNAs that induce ckRNAi. In a current study, we have identified putative RNA-binding proteins (RBPs) in Botrytis EVs, which might be important for the ck-sRNA transport process. In this subproject, we aim at revealing the functions of the Botrytis AGOs and other types of fungal EV-RBPs. These discoveries will not only improve our understanding of the ckRNAi mechanism, but also promise to deliver valuable information to translate into innovative RNA-based plant protection strategies.