title: Signal molecules in the peanut-bradyrhizobia interaction.
abstract: Main nodulation signal molecules in the peanut-bradyrhizobia interaction were examined. Flavonoids exuded by Arachis hypogaea L. cultivar Tegua were genistein, daidzein and chrysin, the latest being released in lower quantities. Thin layer chromatography analysis from genistein-induced bacterial cultures of three peanut bradyrhizobia resulted in an identical Nod factor pattern, suggesting low variability in genes involved in the synthesis of these molecules. Structural study of Nod factor by mass spectrometry and NMR analysis revealed that it shares a variety of substituents with the broad-host-range Rhizobium sp. NGR234 and Bradyrhizobium spp. Nodulation assays in legumes nodulated by these rhizobia demonstrated differences between them and the three peanut bradyrhizobia. The three isolates were classified as Bradyrhizobium sp. Their fixation gene nifD and the common nodulation genes nodD and nodA were also analyzed.
authors.affiliation: Departamento de Ciencias Naturales, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Enlace Rutas 8 y 36 Km 601, 5800, Río Cuarto, Córdoba, Argentina.
authors.forename: Tania
authors.initials: T
authors.lastname: Taurian
authors.forename: Belén
authors.initials: B
authors.lastname: Morón
authors.forename: María E
authors.initials: ME
authors.lastname: Soria-Díaz
authors.forename: Jorge G
authors.initials: JG
authors.lastname: Angelini
authors.forename: Pilar
authors.initials: P
authors.lastname: Tejero-Mateo
authors.forename: Antonio
authors.initials: A
authors.lastname: Gil-Serrano
authors.forename: Manuel
authors.initials: M
authors.lastname: Megías
authors.forename: Adriana
authors.initials: A
authors.lastname: Fabra
mesh_terms: D010367:Arachis / Q000737:chemistry* / Q000382:microbiology* / Q000502:physiology; D020369:Bradyrhizobium / Q000737:chemistry* / Q000145:classification / Q000235:genetics / Q000502:physiology; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D005419:Flavonoids / Q000737:chemistry / Q000378:metabolism; D008070:Lipopolysaccharides / Q000737:chemistry / Q000378:metabolism; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D053204:Root Nodules, Plant / Q000737:chemistry / Q000378:metabolism / Q000382:microbiology; D017422:Sequence Analysis, DNA; D012988:Soil Microbiology; D013045:Species Specificity; D013559:Symbiosis
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005419:Flavonoids; D008070:Lipopolysaccharides; D012336:RNA, Ribosomal, 16S