title: Polymorphic infection and organogenesis patterns induced by a Rhizobium leguminosarum isolate from Lotus root nodules are determined by the host genotype.
abstract: To sample the natural variation in genes controlling compatibility in the legume-rhizobium symbiosis, we isolated rhizobia from nodules of endemic Lotus species from 21 sites across Europe. The majority of isolates were identified as Mesorhizobium- or Bradyrhizobium-related and formed nitrogen-fixing root nodules on Lotus corniculatus and L. pendunculatus, respectively, thus confirming previously defined cross-inoculation groups. Rhizobium leguminosarum (Rl) strain Norway, isolated from L. corniculatus nodules, displayed an exceptional phenotypic variation on different Lotus genotypes. On L. burttii, Rl Norway formed infected nodules, whereas tumors and elongated infected swellings were induced on L. glaber and L. japonicus ecotype Nepal, respectively. A symbiosis- and Nod-factor-responsive promoter:uidA fusion was strongly and rapidly induced in L. japonicus Gifu, but infection threads or signs of nodule organogenesis were absent. This complex phenotypic pattern was not mimicked by either of three engineered R. leguminosarum bv viciae strains producing different Nod-factor variants. Intriguingly, Rl Norway formed infection threads on Pisum sativum cv Sparkle, but failed to induce organogenesis. Rl Norway thus uncovered variation in symbiotic capabilities among diploid Lotus species and ecotypes that are obscured by optimally adapted M. loti strains. These contrasting infection and organogenesis phenotypes reveal recent diversification of recognition determinants in Lotus.
authors.affiliation: Faculty of Biology, Genetics, University of Munich (LMU), Grosshaderner Strasse 2-4, 82152 , Martinsried, Germany.
authors.forename: Jasmin A
authors.initials: JA
authors.lastname: Gossmann
authors.affiliation: Faculty of Biology, Genetics, University of Munich (LMU), Grosshaderner Strasse 2-4, 82152 , Martinsried, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Markmann
authors.affiliation: Faculty of Biology, Genetics, University of Munich (LMU), Grosshaderner Strasse 2-4, 82152 , Martinsried, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Brachmann
authors.affiliation: Faculty of Biology, Evolutionary Biology, University of Munich (LMU), Grosshaderner Strasse 2-4, 82152, Martinsried, Germany.
authors.forename: Laura E
authors.initials: LE
authors.lastname: Rose
authors.affiliation: Faculty of Biology, Genetics, University of Munich (LMU), Grosshaderner Strasse 2-4, 82152 , Martinsried, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Parniske
mesh_terms: D020369:Bradyrhizobium / Q000302:isolation & purification; D005060:Europe; D005838:Genotype; D005966:Glucuronidase / Q000235:genetics; D054884:Host-Pathogen Interactions / Q000235:genetics*; D000070116:Lotus / Q000235:genetics* / Q000382:microbiology; D059128:Mesorhizobium / Q000302:isolation & purification; D038081:Organogenesis / Q000235:genetics*; D010641:Phenotype; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology*; D055170:Plant Root Nodulation / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D015203:Reproducibility of Results; D016961:Rhizobium leguminosarum / Q000302:isolation & purification*; D053204:Root Nodules, Plant / Q000235:genetics / Q000382:microbiology*; D013559:Symbiosis / Q000235:genetics; D015533:Transcriptional Activation
chemical_list: D005966:Glucuronidase