title: Inactivation of the Sinorhizobium fredii HH103 rhcJ gene abolishes nodulation outer proteins (Nops) secretion and decreases the symbiotic capacity with soybean.
abstract: It has been postulated that nodulation outer proteins (Nops) avoid effective nodulation of Sinorhizobium fredii USDA257 to nodulate with American soybeans. S. fredii HH103 naturally nodulates with both Asiatic (non-commercial) and American (commercial) soybeans. Inactivation of the S. fredii HH103 gene rhcJ, which belongs to the tts (type III secretion) cluster, abolished Nop secretion and decreased its symbiotic capacity with the two varieties of soybeans. S. fredii strains HH103 and USDA257, that only nodulates with Asian soybeans, showed different SDS-PAGE Nop profiles, indicating that these strains secrete different sets of Nops. In coinoculation experiments, the presence of strain USDA257 provoked a clear reduction of the nodulation ability of strain HH103 with the American soybean cultivar Williams. These results suggest that S. fredii Nops can act as either detrimental or beneficial symbiotic factors in a strain-cultivar-dependent manner. Differences in the flavonoid-mediated expression of rhcJ with respect to nodA were also detected. In addition, one of the Nops secreted by strain HH103 was identified as NopA.
authors.affiliation: Department of Microbiology, Faculty of Biology, University of Sevilla, Spain.
authors.forename: Maria do C C P
authors.initials: Mdo C
authors.lastname: de Lyra
authors.forename: F Javier
authors.initials: FJ
authors.lastname: Lopez-Baena
authors.forename: Nuria
authors.initials: N
authors.lastname: Madinabeitia
authors.forename: Jośe María
authors.initials: JM
authors.lastname: Vinardell
authors.forename: Maria del Rosario
authors.initials: Mdel R
authors.lastname: Espuny
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Cubo
authors.forename: Ramón Andrés
authors.initials: RA
authors.lastname: Belloguin
authors.forename: Jośe Enrique
authors.initials: JE
authors.lastname: Ruiz-Sainz
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Ollero
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D020868:Gene Silencing; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D042181:Sinorhizobium fredii / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D013025:Glycine max / Q000254:growth & development / Q000382:microbiology*; D013559:Symbiosis
chemical_list: D001426:Bacterial Proteins