Int'l Research Team Finds New Receptor Used in Symbiosis between Legumes and Rhizobia

An international team of experts from Denmark, Italy, France, and Japan identified a new receptor involved in symbiosis between legumes and nitrogen-fixing rhizobia. The results are published in eLife journal.

To start symbiosis, the legumes use certain receptor proteins that can recognize the Nod factor proteins produced by bacteria which are crucial in establishing the host-nonhost link between legumes and rhizobia. The presence of two well-known Nod factor receptors (NFR1 and NFR5) belonging to a large family of so-called LysM receptor kinase proteins implies that other similar receptors may be involved in Nod factor signaling as well. Thus, the researchers identified the role of another LysM receptor kinase called NRFe by studying a model legume species, Lotus japonicus.

Their findings showed that NFRe and NFR1 share similar and distinct biochemical and molecular characteristics. NRFe is expressed primarily in the cells located in a specific area on the surface of the roots. Compared to NFR1, NFRe has a restricted signaling capacity restricted to the outer root cell layer. When NRFe was mutated, less Nod factor signaling was activated inside the root and fewer nodules were formed.

NFR1-type receptors have also been found to be present in other plants that do not form a symbiotic relationship with rhizobial bacteria. This finding could provide a basis for new biotechnological targets in non-symbiotic crops, to enhance their growth in nutrient-limiting conditions.

Read the news release from Aarhus University.