title: Sinorhizobium                      fredii HH103 does not strictly require KPS and/or EPS to nodulate Glycyrrhiza uralensis, an indeterminate nodule-forming legume.
abstract: The Sinorhizobium fredii HH103 rkp-1 region, which is involved in capsular polysaccharide (KPS) biosynthesis, is constituted by the rkpU,                         rkpAGHIJ, and kpsF3 genes. Two mutants in this region affecting the rkpA (SVQ536) and rkpI (SVQ538) genes were constructed. Polyacrylamide gel electrophoresis and (1)H-NMR analyses did not detect KPS in these mutants. RT-PCR experiments indicated that, most probably, the rkpAGHI genes are cotranscribed. Glycine max cultivars (cvs.) Williams and Peking inoculated with mutants SVQ536 and SVQ538 showed reduced nodulation and symptoms of nitrogen starvation. Many pseudonodules were also formed on the American cv. Williams but not on the Asiatic cv. Peking, suggesting that in the determinate nodule-forming S. fredii-soybean symbiosis, bacterial KPS might be involved in determining cultivar-strain specificity. S. fredii HH103 mutants unable to produce KPS or exopolysaccharide (EPS) also showed reduced symbiotic capacity with Glycyrrhiza uralensis, an indeterminate nodule-forming legume. A HH103 exoA-rkpH double mutant unable to produce KPS and EPS was still able to form some nitrogen-fixing nodules on G. uralensis. Thus, here we describe for the first time a Sinorhizobium mutant strain, which produces neither KPS nor EPS is able to induce the formation of functional nodules in an indeterminate nodule-forming legume.
authors.affiliation: Departamento de Microbiología, Universidad de Sevilla, Avda. Reina Mercedes 6, 41012 Sevilla, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Margaret-Oliver
authors.forename: Wang
authors.initials: W
authors.lastname: Lei
authors.forename: Maribel
authors.initials: M
authors.lastname: Parada
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Rodríguez-Carvajal
authors.forename: Juan C
authors.initials: JC
authors.lastname: Crespo-Rivas
authors.forename: Ángeles
authors.initials: Á
authors.lastname: Hidalgo
authors.forename: Antonio
authors.initials: A
authors.lastname: Gil-Serrano
authors.forename: Javier
authors.initials: J
authors.lastname: Moreno
authors.forename: Dulce N
authors.initials: DN
authors.lastname: Rodríguez-Navarro
authors.forename: Ana
authors.initials: A
authors.lastname: Buendía-Clavería
authors.forename: Javier
authors.initials: J
authors.lastname: Ollero
authors.forename: José E
authors.initials: JE
authors.lastname: Ruiz-Sainz
authors.forename: José M
authors.initials: JM
authors.lastname: Vinardell
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D005419:Flavonoids / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D005798:Genes, Bacterial / Q000235:genetics; D005816:Genetic Complementation Test; D029882:Glycyrrhiza uralensis / Q000378:metabolism / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D009154:Mutation; D009586:Nitrogen Fixation / Q000235:genetics; D011135:Polysaccharides, Bacterial / Q000235:genetics / Q000378:metabolism*; D053204:Root Nodules, Plant / Q000378:metabolism; D020579:Sinorhizobium / Q000235:genetics / Q000378:metabolism; D042181:Sinorhizobium fredii / Q000235:genetics / Q000378:metabolism*; D013025:Glycine max / Q000235:genetics / Q000378:metabolism / Q000382:microbiology; D013559:Symbiosis / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D005419:Flavonoids; D011135:Polysaccharides, Bacterial; C105275:RkpI protein, Rhizobium