title: Mutation in the pssA gene involved in exopolysaccharide synthesis leads to several physiological and symbiotic defects in Rhizobium leguminosarum bv. trifolii.
abstract: The symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum bv. trifolii 24.2 secretes large amounts of acidic exopolysaccharide (EPS), which plays a crucial role in establishment of effective symbiosis with clover. The biosynthesis of this heteropolymer is conducted by a multi-enzymatic complex located in the bacterial inner membrane. PssA protein, responsible for the addition of glucose-1-phosphate to a polyprenyl phosphate carrier, is involved in the first step of EPS synthesis. In this work, we characterize R. leguminosarum bv. trifolii strain Rt270 containing a mini-Tn5 transposon insertion located in the 3'-end of the pssA gene. It has been established that a mutation in this gene causes a pleiotropic effect in rhizobial cells. This is confirmed by the phenotype of the mutant strain Rt270, which exhibits several physiological and symbiotic defects such as a deficiency in EPS synthesis, decreased motility and utilization of some nutrients, decreased sensitivity to several antibiotics, an altered extracellular protein profile, and failed host plant infection. The data of this study indicate that the protein product of the pssA gene is not only involved in EPS synthesis, but also required for proper functioning of Rhizobium leguminosarum bv. trifolii cells.
authors: Department of Genetics and Microbiology, Institute of Microbiology and Biotechnology, Maria Curie-Sklodowska University, Akademicka 19 st., Lublin 20-033, Poland. mon.jan@poczta.umcs.lublin.pl.
authors: Monika
authors: M
authors: Janczarek
authors: Kamila
authors: K
authors: Rachwał
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D003902:Detergents / Q000494:pharmacology; D000431:Ethanol / Q000494:pharmacology; D016680:Genome, Bacterial; D016695:Glycosyltransferases / Q000235:genetics* / Q000378:metabolism; D029902:Medicago / Q000382:microbiology; D055442:Metabolome; D008826:Microbial Sensitivity Tests; D016296:Mutagenesis; D010641:Phenotype; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D016961:Rhizobium leguminosarum / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D013559:Symbiosis
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003902:Detergents; D011135:Polysaccharides, Bacterial; D000431:Ethanol; D016695:Glycosyltransferases; C412464:PssA protein, Rhizobium leguminosarum