Soybean is one of the most important plant-based protein sources for food and feed. This legume acts as a natural nitrogen fertilizer by establishing a symbiotic relationship with nitrogen-fixing rhizobia in a process called nodulation. As nodulation is energetically costly, the number of formed nodules is tightly regulated through a systemic pathway called autoregulation of nodulation (AON). The key component acting at the final stages of AON is TOO MUCH LOVE (TML), a root factor inhibiting nodule formation. TML is a Kelch repeat F-box containing protein, hence predicted to mediate AON signaling via ubiquitination of still unknown target proteins. Despite long-lasting research efforts, the TML targets and interactors as well as the complete control mechanism remain elusive. The goal of my project is to identify interactors and ubiquitination targets of TML using ubiquitinomics, shotgun proteomics and interactomics. Novel TML signaling components will be functionally characterized to unravel their mode-of-action during AON. This project will advance our knowledge on the molecular mechanisms by which TML regulates nodulation in response to rhizobia, which will guide future research towards an optimized nodulation control to face increased food demands and minimize the use of nitrogen fertilizers.