Executive Summary : | This project aims to understand the signaling involved in the formation of the nitrogen-fixing symbiosis between legumes and rhizobia bacteria. The interaction requires a mutual exchange of signals between the plant and its endosymbiotic partner, leading to chronic intracellular infection. The study uses legume Medicago truncatula and Gram negative bacteria Sinorhizobium meliloti as a model system. Infection of M. truncatula with S. meliloti leads to the formation of nodules in the roots, where S. meliloti differentiates into enlarged, highly polyploid, nitrogen-fixing bacteroids. This differentiation is driven by host defensin-like Nodule-Specific Cysteine-Rich (NCR) peptides, which orchestrate the adaptation of free-living bacteria into intracellular residents. The researchers are applying biochemical and molecular approaches to understand the role of these peptides in intracellular lifestyle adaptation of S. meliloti within the nodule of Medicago plants. They are investigating how bacteria can survive inside host cells and how diverse physiological, biochemical, and genetic changes help bacteria to sustain within host cells.
The intensively studied NCR247 peptide is chosen to address the issue of how NCR peptide governs the molecular mechanism leading to bacteroids inside the nodules. NCR peptides have signaling functions and some possess bactericidal activities, making them attractive prototypes for developing antibiotics. The research offers new insights into the complex interaction between a bacterium and a eukaryotic host, where the bacterium establishes a chronic intracellular infection. |