title: Culturable endophytic bacterial communities associated with field-grown soybean.
abstract: OBJECTIVE
  Assess the diversity of the culturable endophytic bacterial population associated with transgenic and nontransgenic soybean grown in field trial sites in Brazil and characterize them phenotypically and genotypically focusing on characteristics related to plant growth promotion.
  
  
  RESULTS
  Endophytic bacteria were isolated from roots, stems and leaves of soybean cultivars (nontransgenic (C) and glyphosate-resistant (GR) transgenic soybean), including the isogenic BRS133 and BRS245RR. Significant differences were observed in bacterial densities in relation to genotype and tissue from which the isolates were obtained. The highest number of bacteria was observed in roots and in GR soybean. Based on characteristics related to plant growth promotion, 54 strains were identified by partial 16S rRNA sequence analysis, with most of the isolates belonging to the species Enterobacter ludwigii and Variovorax paradoxus. Among the isolates, 44·4% were able to either produce indoleacetic acid (IAA) or solubilize phosphates, and 9·2% (all from GR soybean) presented both plant growth-promoting activities.
  
  
  CONCLUSIONS
  The results from this study indicate that the abundance of endophytic bacterial communities of soybean differs between cultivars and in general it was higher in the transgenic cultivars than in nontransgenic cultivars. BRS 245 RR exhibited no significant difference in abundance compared to nontransgenic BRS133. This suggests that the impact of the management used in the GR soybean fields was comparable with the impacts of some enviromental factors. However, the bacterial endophytes associated to GR and nontransgenic soybean were different. The soybean-associated bacteria showing characteristics related to plant growth promotion were identified as belonging to the species Pantoea agglomerans and Variovorax paradoxus.
  
  
  CONCLUSIONS
  Our study demonstrated differences concerning compostion of culturable endophytic bacterial population in nontransgenic and transgenic soybean.
authors.affiliation: Agronomy Department, Post Graduation Program in Agronomy, Londrina State University, Londrina, PR, Brazil.
authors.forename: K B
authors.initials: KB
authors.lastname: de Almeida Lopes
authors.affiliation: Embrapa Trigo, Passo Fundo, RS, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Carpentieri-Pipolo
authors.affiliation: Agronomy Department, Post Graduation Program in Agronomy, Londrina State University, Londrina, PR, Brazil.
authors.forename: T H
authors.initials: TH
authors.lastname: Oro
authors.affiliation: Agronomy Department, Post Graduation Program in Agronomy, Londrina State University, Londrina, PR, Brazil.
authors.forename: E
authors.initials: E
authors.lastname: Stefani Pagliosa
authors.affiliation: Industrial Biotechnology Group, International Center for Genetic Engineering and Biotechnology, Trieste, Italy.|IBioBA-ICGEB, Polo Cientifico Tecnologico, Buenos Aires, Argentina.
authors.forename: G
authors.initials: G
authors.lastname: Degrassi
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001938:Brazil; D060026:Endophytes / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D020636:Pantoea / Q000235:genetics; D018515:Plant Leaves / Q000382:microbiology; D018517:Plant Roots / Q000382:microbiology; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D013025:Glycine max / Q000254:growth & development / Q000382:microbiology*
chemical_list: D007210:Indoleacetic Acids; D012336:RNA, Ribosomal, 16S; C030737:indoleacetic acid
keywords: Bacteria-plant interaction; endophytic bacteria; exopolisaccharides; glyphosate-tolerant soybean; indoleacetic acid; motility; phosphate solubilization