The project focusses on how interactions between plant roots and neighboring organisms positively influence plant growth. The emphasis is on the symbiosis between legumes and rhizobia, resulting in the formation of new root organs, the nodules, in which the rhizobia reside and fix atmospheric nitrogen for the plant making plant growth independent of nitrogen fertilizers. Medicago truncatula and soybean are the main plants of interest. Additionally, plants engage in numerous interactions with both beneficial and harmful soil organisms. These can be bacteria and fungi but also other plants, such as Orobanchaceae sp.. It is thus of great importance for plants to attract friends and repel foes. This intra- and interkingdom communication occurs through molecular signaling pathways involving the secretion and sensing of various metabolites and proteins. The project will combine root microbiome analysis with proteomics, transcriptomics, genetic approaches and high throughput phenotyping to elucidate the mechanisms by which microbes communicate with plants roots resulting in beneficial effects for the plants.