The typA gene is required for stress adaptation as well as for symbiosis of Sinorhizobium meliloti 1021 with certain Medicago truncatula lines.
In this article, we describe the typA gene of Sinorhizobium meliloti, the orthologue of typA/bipA genes found in a wide range of bacteria. We found that typA was required for survival of S. meliloti under certain stress conditions, such as growth at low temperature or low pH and in the presence of sodium dodecyl sulfate (SDS). The cold-sensitive phenotype of both Escherichia coli bipA and S. meliloti typA mutants were cross-complemented, indicating that the two genes are functionally equivalent. typA was indispensable for symbiosis on Medicago truncatula Jemalong and F83005.5 and contributes to the full efficiency of symbiosis on other host plant lines such as DZA315.16 or several cultivars of M. sativa. Hence, the symbiotic requirement for typA is host dependent. Interestingly, the symbiotic defect was different on Jemalong and F83005.5 plants, thus indicating that typA is required at a different stage of the symbiotic interaction.
Laboratoire des Interactions Plantes Microorganismes, Centre National de la Recherche Scientifique (UMR 2594), Institut National de la Recherche Agronomique (UMR 441), BP27, 31326 Castanet, Tolosan cedex, France.
Ernö
E
Kiss
Thierry
T
Huguet
Véréna
V
Poinsot
Jacques
J
Batut
D000222:Adaptation, Physiological / Q000235:genetics* / Q000502:physiology; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003080:Cold Temperature; D017124:Conserved Sequence / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D020558:GTP Phosphohydrolases / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D018506:Gene Expression Regulation, Plant; D005798:Genes, Bacterial; D005816:Genetic Complementation Test; D006863:Hydrogen-Ion Concentration; D008070:Lipopolysaccharides / Q000378:metabolism; D029902:Medicago / Q000235:genetics* / Q000382:microbiology / Q000502:physiology; D008969:Molecular Sequence Data; D009154:Mutation; D009586:Nitrogen Fixation / Q000235:genetics* / Q000502:physiology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000382:microbiology / Q000502:physiology; D017386:Sequence Homology, Amino Acid; D016962:Sinorhizobium meliloti / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013559:Symbiosis / Q000235:genetics* / Q000502:physiology
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008070:Lipopolysaccharides; D010750:Phosphoproteins; D012967:Sodium Dodecyl Sulfate; D020558:GTP Phosphohydrolases; C408370:typA protein, E coli