A pyrF auxotrophic mutant of Sinorhizobium fredii HH103 impaired in its symbiotic interactions with soybean and other legumes.
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.
Crespo-Rivas
Juan C
JC
Department of Microbiology, Faculty of Biology, University of Sevilla, Sevilla, Spain.
Margaret
Isabel
I
Pérez-Montaño
Francisco
F
López-Baena
Francisco J
FJ
Vinardell
José M
JM
Ollero
Francisco J
FJ
Moreno
Javier
J
Ruiz-Sainz
José E
JE
Buendía-Clavería
Ana M
AM
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
D001426:Bacterial Proteins; D014498:Uracil; D009964:Orotidine-5'-Phosphate Decarboxylase