title: A pyrF auxotrophic mutant of Sinorhizobium fredii HH103 impaired in its symbiotic interactions with soybean and other legumes.
abstract: Transposon Tn5-Mob mutagenesis allowed the selection of a Sinorhizobium fredii HH103 mutant derivative (SVQ 292) that requires the presence of uracil to grow in minimal media. The mutated gene, pyrF, codes for an orotidine-5 - monophosphate decarboxylase (EC 4.1.1.23). Mutant SVQ 292 and its parental prototrophic mutant HH103 showed similar Nod-factor and lipopolysaccharide profiles. The symbiotic properties of mutant SVQ 292 were severely impaired with all legumes tested. Mutant SVQ 292 formed small ineffective nodules on Cajanus cajan and abnormal nodules (pseudonodules) unable to fix nitrogen on Glycine max (soybean), Macroptitlium atropurpureum, Indigofera tinctoria, and Desmodium canadense. It also did not induce any macroscopic response in Macrotyloma axillare roots. The symbiotic capacity of SVQ 292 with soybean was not enhanced by the addition of uracil to the plant nutritive solution.
authors: Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain.
authors: Juan C
authors: JC
authors: Crespo-Rivas
authors: Isabel
authors: I
authors: Margaret
authors: Francisco
authors: F
authors: Pérez-Montaño
authors: Francisco J
authors: FJ
authors: López-Baena
authors: José M
authors: JM
authors: Vinardell
authors: Francisco J
authors: FJ
authors: Ollero
authors: Javier
authors: J
authors: Moreno
authors: José E
authors: JE
authors: Ruiz-Sainz
authors: Ana M
authors: AM
authors: Buendía-Clavería
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D007887:Fabaceae / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D009964:Orotidine-5'-Phosphate Decarboxylase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D042181:Sinorhizobium fredii / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D013025:Glycine max / Q000382:microbiology*; D013559:Symbiosis / Q000235:genetics; D014498:Uracil / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D014498:Uracil; D009964:Orotidine-5'-Phosphate Decarboxylase