Widespread Bradyrhizobium distribution of diverse Type III effectors that trigger legume nodulation in the absence of Nod factor.

The establishment of the rhizobium-legume symbiosis is generally based on plant perception of Nod factors (NFs) synthesized by the bacteria. However, some Bradyrhizobium strains can nodulate certain legume species, such as Aeschynomene spp. or Glycine max, independently of NFs, and via two different processes that are distinguished by the necessity or not of a type III secretion system (T3SS).

Type III effector provides a novel symbiotic pathway in legume-rhizobia symbiosis.

Rhizobia form nodules on the roots of legumes and fix atmospheric nitrogen into ammonia, thus supplying it to host legumes. In return, plants supply photosynthetic products to maintain rhizobial activities. In most cases, rhizobial Nod factors (NFs) and their leguminous receptors (NFRs) are essential for the establishment of symbiosis.

Multiple Domains in the Rhizobial Type III Effector Bel2-5 Determine Symbiotic Efficiency With Soybean.

utilizes the type III effector Bel2-5 for nodulation in host plants in the absence of Nod factors (NFs). In soybean plants carrying the allele, however, Bel2-5 causes restriction of nodulation by triggering immune responses. Bel2-5 shows similarity with XopD of the phytopathogen pv.

Rhizobia use a pathogenic-like effector to hijack leguminous nodulation signalling.

Legume plants form a root-nodule symbiosis with rhizobia. This symbiosis establishment generally relies on rhizobium-produced Nod factors (NFs) and their perception by leguminous receptors (NFRs) that trigger nodulation. However, certain rhizobia hijack leguminous nodulation signalling via their type III secretion system, which functions in pathogenic bacteria to deliver effector proteins into host cells.