title: Isolation of N2 -fixing rhizobacteria from Lolium perenne and evaluating their plant growth promoting traits.
abstract: Twenty one dinitrogen (N2 )-fixing bacteria were isolated from the rhizosphere of Lolium perenne grown for more than 10 years without N-fertilization. The nearly complete sequence of the 16S rRNA gene of each strain and pairwise alignments among globally aligned sequences of the 16S rRNA genes clustered them into nine different groups. Out of the 21 strains, 11 were members of genus Bacillus, 3 belonged to each one of genera Paenibacillus and Pseudoxanthomonas, and the remaining 2 strains to each one of genera Burkholderia and Staphylococcus, respectively. A representative strain from each group contained the nifH gene and fixed atmospheric N2 as determined by the acetylene-dependent ethylene production assay (acetylene reduction activity, ARA). The nine selected strains were also examined to behave as plant growth promoting bacteria (PGPRs) including their ability to act as a biocontrol agent. The nine representative strains produced indol acetic acid (IAA) and solubilized calcium triphosphate, five of them, strains C2, C3, C12, C15, and C16, had ACC deaminase activity, and strains C2, C3, C4, C12, C16, and C17 produced siderophores. Strains C13, C16, and C17 had the capability to control growth of the pathogen Fusarium oxysporum mycelial growth in vitro. PCA analysis of determined PGPR properties showed that ARA, ACC deaminase activity, and siderophore production were the most valuable as they had the maximal contribution to the total variance.
authors.affiliation: Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Granada, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Castellano-Hinojosa
authors.affiliation: Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Granada, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Correa-Galeote
authors.affiliation: Professional Sportsverd Football S.L., Badalona, Spain.
authors.forename: Josep
authors.initials: J
authors.lastname: Palau
authors.affiliation: Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín, Granada, Spain.
authors.forename: Eulogio J
authors.initials: EJ
authors.lastname: Bedmar
mesh_terms: D000114:Acetylene / Q000378:metabolism; D000598:Amino Acids, Cyclic / Q000378:metabolism; D000935:Antifungal Agents / Q000494:pharmacology; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000378:metabolism; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D005670:Fusarium / Q000187:drug effects / Q000472:pathogenicity; D007210:Indoleacetic Acids / Q000378:metabolism; D008129:Lolium / Q000382:microbiology*; D005810:Multigene Family; D009586:Nitrogen Fixation / Q000235:genetics*; D010088:Oxidoreductases / Q000235:genetics; D010802:Phylogeny; D063245:Plant Development; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D058441:Rhizosphere; D017262:Siderophores / Q000096:biosynthesis; D012988:Soil Microbiology
chemical_list: D000598:Amino Acids, Cyclic; D000935:Antifungal Agents; D001426:Bacterial Proteins; D007210:Indoleacetic Acids; D010937:Plant Growth Regulators; D012336:RNA, Ribosomal, 16S; D017262:Siderophores; C023863:1-aminocyclopropane-1-carboxylic acid; D010088:Oxidoreductases; C029130:nitrogenase reductase; D000114:Acetylene
keywords: 16S rRNA gene; PGPRs; Phylogenetic tree; Ryegrass; nifH gene