title: The incomplete substitution of lipopolysaccharide with O-chain prevents the establishment of effective symbiosis between Mesorhizobium loti NZP2213.1 and Lotus corniculatus.
abstract: Mesorhizobium loti NZP2213.1 mutant obtained after random Tn5 mutagenesis of M. loti NZP2213 was inefficient in nitrogen fixation on Lotus corniculatus. The transposon insertion was located within an ORF with a sequence similarity to a putative glycosyl transferase from Caulobacter crescentus. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that the mutant produced LPS of the same O-chain length but only half of the entire smooth LPS, compared to that of the parental strain. A greater diversity of the anomeric region as determined by NMR spectroscopy, reflected structural differences in the mutant repeating units represented by 6-deoxytalose, 2-OAc-6-deoxytalose, and 2-OMe-6-deoxytalose. In contrast to the completely O-acetylated 6-deoxytalose in wild-type OPS only partial O-acetylation was found in the mutant. The decrease of the LPS species with O-chains seems to be correlated with 6-deoxytalose deficiency. Microscopic examination of the nodules induced by the mutant revealed disturbances in infection thread development and premature senescence of symbiosomes. The impairment of mutant-induced symbiosomes to sustain latter stages of symbiosis could be a consequence of the decreased ratio of the hydrophobic to the hydrophilic LPSs.
authors.affiliation: Department of General Microbiology, M. Curie-Skłodowska University, Akademicka, Lublin, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Turska-Szewczuk
authors.forename: Barbara
authors.initials: B
authors.lastname: Lotocka
authors.forename: Jolanta
authors.initials: J
authors.lastname: Kutkowska
authors.forename: Jarosław
authors.initials: J
authors.lastname: Król
authors.forename: Teresa
authors.initials: T
authors.lastname: Urbanik-Sypniewska
authors.forename: Ryszard
authors.initials: R
authors.lastname: Russa
mesh_terms: D020561:Alphaproteobacteria / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics; D003837:Deoxy Sugars / Q000378:metabolism; D016695:Glycosyltransferases / Q000235:genetics; D006601:Hexoses / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D000070116:Lotus / Q000382:microbiology / Q000502:physiology*; D016254:Mutagenesis, Insertional; D053204:Root Nodules, Plant / Q000382:microbiology / Q000502:physiology; D013559:Symbiosis
chemical_list: D001426:Bacterial Proteins; D003837:Deoxy Sugars; D006601:Hexoses; D008070:Lipopolysaccharides; C011754:6-deoxytalose; D016695:Glycosyltransferases