title: Phylogenetic assignment and mechanism of action of a crop growth promoting Rhizobium radiobacter strain used as a biofertiliser on graminaceous crops in Russia.
abstract: The taxonomic position of "Agrobacterium radiobacter strain 204," used in Russia as a cereal crop growth promoting inoculant, was derived by a polyphasic approach. The phenotypic analyses gave very similar biochemical profiles for strain 204, Rhizobium radiobacter NCIMB 9042 (formerly the A. radiobacter type strain) and R. radiobacter NCIMB 13307 (formerly the Agrobacterium tumefaciens type strain). High percentage similarities, above the species separation level, were observed between the 16S rRNA, fusA and rpoB housekeeping gene sequences of these three strains, and the genomic DNA-DNA hybridisation of strain 204 against the type strain of R. radiobacter NCIMB 9042 was over 70%. Strain 204 is not phytopathogenic and it does not fix atmospheric N2 or form a physical association with the roots of barley. Strain 204 culture and culture supernatant stimulated the rate of mobilisation of seed reserves of barley in darkness and promoted its shoot growth in the light. Gibberellic acid (GA) concentration was 1.3 microM but indole acetic acid was undetectable (< 50 nM) in cultures of strain 204. It is concluded that strain 204 is phenotypically and genotypically very similar to the current R. radiobacter type strain and that the mechanism of its effect on growth of cereals is via the production of plant growth promoting substances. GA is likely to play an important role in the strain 204 stimulation of early growth of barley.
authors.affiliation: Department of Biology, University of York, P.O. Box 373, University Road, Heslington, York, UK.
authors.forename: David R
authors.initials: DR
authors.lastname: Humphry
authors.forename: Mitchell
authors.initials: M
authors.lastname: Andrews
authors.forename: Scott R
authors.initials: SR
authors.lastname: Santos
authors.forename: Euan K
authors.initials: EK
authors.lastname: James
authors.forename: Lioubov V
authors.initials: LV
authors.lastname: Vinogradova
authors.forename: Liamara
authors.initials: L
authors.lastname: Perin
authors.forename: Veronica M
authors.initials: VM
authors.lastname: Reis
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Cummings
mesh_terms: D016960:Agrobacterium tumefaciens / Q000145:classification* / Q000235:genetics / Q000502:physiology*; D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D018556:Crops, Agricultural / Q000254:growth & development / Q000382:microbiology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D020459:Genes, rRNA; D005875:Gibberellins / Q000096:biosynthesis; D001467:Hordeum / Q000254:growth & development / Q000382:microbiology; D007210:Indoleacetic Acids / Q000378:metabolism; D008969:Molecular Sequence Data; D009586:Nitrogen Fixation / Q000235:genetics; D009693:Nucleic Acid Hybridization; D010088:Oxidoreductases / Q000235:genetics; D020653:Peptide Elongation Factor G / Q000235:genetics; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology; D018520:Plant Shoots / Q000254:growth & development; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012426:Russia; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D011198:Solanum tuberosum / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005875:Gibberellins; D007210:Indoleacetic Acids; D020653:Peptide Elongation Factor G; D012336:RNA, Ribosomal, 16S; C030737:indoleacetic acid; C007842:gibberellic acid; D010088:Oxidoreductases; C029130:nitrogenase reductase; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit