title: Physical organization of phytobeneficial genes nifH and ipdC in the plant growth-promoting rhizobacterium Azospirillum lipoferum 4VI.
abstract: The physical organization of phytobeneficial genes was investigated in the plant growth-promoting rhizobacterium Azospirillum lipoferum 4VI by hybridization screening of a bacterial artificial chromosome (BAC) library. Pulsed-field gel electrophoresis gave an estimated 5.7-Mb genome size for strain 4VI and a coverage level of 9 for the BAC library. The phytobeneficial genes nifH (associative nitrogen fixation) and ipdC (synthesis of the phytohormone indoleacetic acid) are chromosomal, but no BAC clone containing both genes was found, pointing to the absence of any genetic island containing nifH and ipdC. A 11.8-kb fragment containing nifH was analyzed. Neighboring genes implicated in nitrogen fixation (nifH, draT, draG) or not (arsC, yafJ and acpD) were organized as in A. brasilense. In contrast, the region located downstream of acpD contained four housekeeping genes (i.e. genes encoding DapF-, MiaB- and FtsY-like proteins, as well as gene amn) and differed totally from the one found in A. brasilense.
authors.affiliation: UMR CNRS 5557 Ecologie Microbienne, Université Claude Bernard (Lyon 1), 43 bd du 11 Novembre, 69622 Villeurbanne cedex, France.
authors.forename: Didier
authors.initials: D
authors.lastname: Blaha
authors.forename: Hervé
authors.initials: H
authors.lastname: Sanguin
authors.forename: Patrick
authors.initials: P
authors.lastname: Robe
authors.forename: Renaud
authors.initials: R
authors.lastname: Nalin
authors.forename: René
authors.initials: R
authors.lastname: Bally
authors.forename: Yvan
authors.initials: Y
authors.lastname: Moënne-Loccoz
mesh_terms: D042081:Azospirillum lipoferum / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D015723:Gene Library; D005798:Genes, Bacterial; D016680:Genome, Bacterial; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics; D010088:Oxidoreductases / Q000235:genetics; D063245:Plant Development; D010937:Plant Growth Regulators / Q000378:metabolism; D010944:Plants / Q000382:microbiology*; D012093:Replicon
chemical_list: D004269:DNA, Bacterial; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; C030737:indoleacetic acid; D010088:Oxidoreductases; C029130:nitrogenase reductase