title: Genetic, physiological and biochemical characterization of Bacillus sp. strain RMB7 exhibiting plant growth promoting and broad spectrum antifungal activities.
abstract: BACKGROUND
  Plant growth promoting rhizobacteria (PGPR) are functionally diverse group of bacteria having immense potential as biofertilizers and biopesticides. Depending upon their function, they may serve as partial replacements for chemical fertilizer or pesticides as an eco-friendly and cost-effective alternatives as compared to their synthetic counterparts. Therefore, isolation, characterization and practical evaluation of PGPRs having the aforementioned multifaceted beneficial characteristics, are essentially required. This study describes the detailed polyphasic characterization of Bacillus sp. strain RMB7 having profound broad spectrum antifungal activity and plant growth promoting potential.
  
  
  RESULTS
  Based on 16S rRNA gene sequencing, strain RMB7 was identified as Bacillus specie. This strain exhibited the production of 8 mg. L(-1)of indole-3-acetic acid (IAA) in tryptophan-supplemented medium. It was able to solubilize 50.6 mg. L(-1) tri-calcium phosphate, reduced 601ηmol acetylene h(-1)/vial and inhibited >70% growth of nine fungal phytopathogens tested in vitro. Under natural pathogen pressure, inoculation with strain RMB7 and RMB7-supernatant conferred resistance by arugula plant against Pythium irregulare with a concurrent growth improvement over non-inoculated plants. The T-RFLP analysis based on 16S rRNA gene showed that inoculation with RMB7 or its supernatant have a major impact on the indigenous rhizosphere bacterial population. Mass spectrometric analysis revealed the production of lipopeptide surfactins as well as iturin A presence in crude extract of RMB7. PCR-amplification further confirmed the presence of genes involved in the biosynthesis of these two bioactive lipopeptide compounds.
  
  
  CONCLUSIONS
  The data show that Bacillus sp. strain RMB7 has multifaceted beneficial characteristics. It may be an ideal plant growth promoting as well as biocontrol agent, for its integrated use in disease and nutrient management strategies.
authors.affiliation: National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, 38000, Pakistan. sairaali962@hotmail.com.|Department of Biology, University of Western Ontario, London, ON, Canada. sairaali962@hotmail.com.
authors.forename: Saira
authors.initials: S
authors.lastname: Ali
authors.affiliation: National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, 38000, Pakistan. shameed58@hotmail.com.
authors.forename: Sohail
authors.initials: S
authors.lastname: Hameed
authors.affiliation: National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, 38000, Pakistan. asmaaslam2001@yahoo.com.
authors.forename: Asma
authors.initials: A
authors.lastname: Imran
authors.affiliation: National Institute for Biotechnology and Genetic Engineering (NIBGE), P.O. Box 577, Jhang Road, Faisalabad, 38000, Pakistan. hamzamgondal@gmail.com.
authors.forename: Mazhar
authors.initials: M
authors.lastname: Iqbal
authors.affiliation: A&L Biologicals, Agroecology Research Service Centre, 2136 Jet stream Road, London, ON, N5V 3P5, Canada. lazarovitsg@alcanada.com.|Department of Biology, University of Western Ontario, London, ON, Canada. lazarovitsg@alcanada.com.
authors.forename: George
authors.initials: G
authors.lastname: Lazarovits
mesh_terms: D000114:Acetylene / Q000378:metabolism; D000935:Antifungal Agents / Q000378:metabolism; D001407:Bacillus / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D011775:Pythium / Q000254:growth & development / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D027343:Rhizome / Q000254:growth & development / Q000382:microbiology
chemical_list: D000935:Antifungal Agents; D007210:Indoleacetic Acids; D012336:RNA, Ribosomal, 16S; C030737:indoleacetic acid; D000114:Acetylene