Targeting microbial pathogens

One of the most important challenges in agricultural production is to safeguard crops from pathogen infection. Uncovering the molecular mechanisms governing plant-microbe interactions can provide new strategies by which to sustainably intensify agriculture and can additionally contribute to our broader understanding of interspecies interactions (1). On page 1126 of this issue, Cai et al. (2) report that plant hosts secrete extracellular vesicles containing small RNA (sRNA), which are taken up by, and lead to silencing of, fungal virulence–related genes during infection (see the figure). These findings address the previously unknown phenomenon by which host sRNA can alter gene expression in other organisms, highlighting the role of extracellular vesicle–mediated transport as a key element of cross-kingdom RNA interference (RNAi). This could be exploited in the development of RNAi-based pathogen control strategies to protect crops.