title: Effect of Cry1Ab protein on rhizobacterial communities of Bt-maize over a four-year cultivation period.
abstract: BACKGROUND
  Bt-maize is a transgenic variety of maize expressing the Cry toxin from Bacillus turingiensis. The potential accumulation of the relative effect of the transgenic modification and the cry toxin on the rhizobacterial communities of Bt-maize has been monitored over a period of four years.
  
  
  RESULTS
  The accumulative effects of the cultivation of this transgenic plant have been monitored by means of high throughput DNA pyrosequencing of the bacterial DNA coding for the 16S rRNA hypervariable V6 region from rhizobacterial communities. The obtained sequences were subjected to taxonomic, phylogenetic and taxonomic-independent diversity studies. The results obtained were consistent, indicating that variations detected in the rhizobacterial community structure were possibly due to climatic factors rather than to the presence of the Bt-gene. No variations were observed in the diversity estimates between non-Bt and Bt-maize.
  
  
  CONCLUSIONS
  The cultivation of Bt-maize during the four-year period did not change the maize rhizobacterial communities when compared to those of the non-Bt maize. This is the first study to be conducted with Bt-maize during such a long cultivation period and the first evaluation of rhizobacterial communities to be performed in this transgenic plant using Next Generation Sequencing.
authors.affiliation: Centro Nacional de Biotecnología, CSIC, Campus de la Universidad Autónoma, Cantoblanco, Madrid, Spain.
authors.forename: Jorge
authors.initials: J
authors.lastname: Barriuso
authors.forename: José R
authors.initials: JR
authors.lastname: Valverde
authors.forename: Rafael P
authors.initials: RP
authors.lastname: Mellado
mesh_terms: D000083722:Bacillus thuringiensis Toxins; D001419:Bacteria / Q000235:genetics* / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D016000:Cluster Analysis; D004731:Endotoxins / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism / Q000382:microbiology*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000254:growth & development*; D017422:Sequence Analysis, DNA / Q000379:methods; D012988:Soil Microbiology; D003313:Zea mays / Q000235:genetics / Q000254:growth & development* / Q000382:microbiology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis