title: Involvement of the syrM and nodD3 genes of Rhizobium meliloti in nod gene activation and in optimal nodulation of the plant host.
abstract: We identified and sequenced the regulatory syrM and nodD3 genes of Rhizobium meliloti 41. Both genes were shown to contribute to optimal nodulation of alfalfa. In R. meliloti strains carrying syrM and nodD3 on plasmid, the nod genes are expressed constitutively, resulting in host-range extension to siratro. This is due to the presence of multiple syrM copies, suggesting that SyrM participates directly in nod gene activation. NodD3 activates nod genes in conjunction with flavonoids and enhances syrM expression, which is controlled also by its own product, NodD2, and two putative trans-acting factors. nodD3 is regulated by SyrM, NodD1, nodD3, the repressor NoIR, and two putative factors.
authors.affiliation: Centre National de la Recherche Scientifique, Institut des Sciences Végétales, Gif-sur-Yvette, France.
authors.forename: E
authors.initials: E
authors.lastname: Kondorosi
authors.forename: M
authors.initials: M
authors.lastname: Buiré
authors.forename: M
authors.initials: M
authors.lastname: Cren
authors.forename: N
authors.initials: N
authors.lastname: Iyer
authors.forename: B
authors.initials: B
authors.lastname: Hoffmann
authors.forename: A
authors.initials: A
authors.lastname: Kondorosi
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D001483:Base Sequence; D002874:Chromosome Mapping; D004268:DNA-Binding Proteins; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D005809:Genes, Regulator / Q000235:genetics*; D006790:Host-Parasite Interactions / Q000235:genetics; D000455:Medicago sativa / Q000382:microbiology*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D017351:N-Acetylglucosaminyltransferases; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D012231:Rhizobium / Q000235:genetics*; D013559:Symbiosis / Q000235:genetics*; D015534:Trans-Activators; D014157:Transcription Factors; D015533:Transcriptional Activation
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D005419:Flavonoids; C061268:NodD3 protein, Sinorhizobium meliloti; D011993:Recombinant Fusion Proteins; C064814:SyrM protein, Rhizobium meliloti; D015534:Trans-Activators; D014157:Transcription Factors; D017351:N-Acetylglucosaminyltransferases; C060771:NodC protein, Rhizobiales