Manipulation of plant metabolism by pathogen effectors: more than just food

To successfully infect plants, pathogens secrete effector proteins to the plant apoplast or inside plant cells, where they suppress plant immunity or interfere with other cellular processes to facilitate infection. Plant metabolism is crucial for most cellular processes and plays a key role in defense against pathogens, making it a major target for pathogen effectors. Effector proteins manipulate host metabolism to provide the pathogen with nutrients or to indirectly suppress plant chemical defense responses. Recent studies have shown that pathogens also utilize effectors to shape the microbiota composition by altering the concentration of certain plant metabolites. Here, we summarize current knowledge on the manipulation of plant metabolism by pathogen effectors. We also discuss what remains unknown regarding the manipulation of host metabolism by pathogen effectors.