title: Nitrogen fixation genetics and regulation in a Pseudomonas stutzeri strain associated with rice.
abstract: The Pseudomonas stutzeri strain A1501 (formerly known as Alcaligenes faecalis) fixes nitrogen under microaerobic conditions in the free-living state and colonizes rice endophytically. The authors characterized a region in strain A1501, corresponding to most of the nif genes and the rnf genes, involved in electron transport to nitrogenase in Rhodobacter capsulatus. The region contained three groups of genes arranged in the same order as in Azotobacter vinelandii: (1) nifB fdx ORF3 nifQ ORF5 ORF6; (2) nifLA-rnfABCDGEF-nifY2/nafY; (3) ORF13 ORF12-nifHDK-nifTY ORF1 ORF2-nifEN. Unlike in A. vinelandii, where these genes are not contiguous on the chromosome, but broken into two regions of the genome, the genes characterized here in P. stutzeri are contiguous and present on a 30 kb region in the genome of this organism. Insertion mutagenesis confirmed that most of the nif and the rnf genes in A1501 were essential for nitrogen fixation. Using lacZ fusions it was found that nif and rnf gene expression was under the control of ntrBC, nifLA and rpoN and that the rnf gene products were involved in the regulation of the nitrogen fixation process.
authors.affiliation: Microbiologie et Environnement, CNRS URA D2172, Institut Pasteur, Paris, France.
authors.forename: Nicole
authors.initials: N
authors.lastname: Desnoues
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, PR China.
authors.forename: Min
authors.initials: M
authors.lastname: Lin
authors.affiliation: Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico.|Microbiologie et Environnement, CNRS URA D2172, Institut Pasteur, Paris, France.
authors.forename: Xianwu
authors.initials: X
authors.lastname: Guo
authors.affiliation: Microbiologie et Environnement, CNRS URA D2172, Institut Pasteur, Paris, France.
authors.forename: Luyan
authors.initials: L
authors.lastname: Ma
authors.affiliation: Microbiologie et Environnement, CNRS URA D2172, Institut Pasteur, Paris, France.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Carreño-Lopez
authors.affiliation: Institut des Sciences du Végétal, CNRS UPR 2355, Bâtiment 23, Avenue de la Terrasse, 91198 Gif sur Yvette, France.|Microbiologie et Environnement, CNRS URA D2172, Institut Pasteur, Paris, France.
authors.forename: Claudine
authors.initials: C
authors.lastname: Elmerich
mesh_terms: D000641:Ammonia / Q000494:pharmacology; D001483:Base Sequence; D002874:Chromosome Mapping; D004269:DNA, Bacterial / Q000235:genetics; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics*; D012275:Oryza / Q000382:microbiology; D010100:Oxygen / Q000494:pharmacology; D010957:Plasmids / Q000235:genetics; D011549:Pseudomonas / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D000641:Ammonia; D010100:Oxygen