title: Assessing the bioconfinement potential of a Nicotiana hybrid platform for use in plant molecular farming applications.
abstract: BACKGROUND
  The introduction of pharmaceutical traits in tobacco for commercial production could benefit from the utilization of a transgene bioconfinement system. It has been observed that interspecific F1Nicotiana hybrids (Nicotiana tabacum × Nicotiana glauca) are sterile and thus proposed that hybrids could be suitable bioconfined hosts for biomanufacturing. We genetically tagged hybrids with green fluorescent protein (GFP), which was used as a visual marker to enable gene flow tracking and quantification for field and greenhouse studies. GFP was used as a useful proxy for pharmaceutical transgenes.
  
  
  RESULTS
  Analysis of DNA content revealed significant genomic downsizing of the hybrid relative to that of N. tabacum. Hybrid pollen was capable of germination in vitro, albeit with a very low frequency and with significant differences between plants. In two field experiments, one each in Tennessee and Kentucky, we detected outcrossing at only one location (Tennessee) at 1.4%. Additionally, from 50 hybrid plants at each field site, formation of 84 and 16 seed was observed, respectively. Similar conclusions about hybrid fertility were drawn from greenhouse crosses. In terms of above-ground biomass, the hybrid yield was not significantly different than that of N. tabacum in the field.
  
  
  CONCLUSIONS
  N. tabacum × N. glauca hybrids show potential to contribute to a bioconfinement- and biomanufacturing host system. Hybrids exhibit extremely low fertility with no difference of green biomass yields relative to N. tabacum. In addition, hybrids are morphologically distinguishable from tobacco allowing for identity preservation. This hybrid system for biomanufacturing would optimally be used where N. glauca is not present and in physical isolation of N. tabacum production to provide total bioconfinement.
authors.affiliation: Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996, USA.
authors.forename: J Hollis
authors.initials: JH
authors.lastname: Rice
authors.forename: Richard E
authors.initials: RE
authors.lastname: Mundell
authors.forename: Reginald J
authors.initials: RJ
authors.lastname: Millwood
authors.forename: Orlando D
authors.initials: OD
authors.lastname: Chambers
authors.forename: C Neal
authors.initials: CN
authors.lastname: Stewart
authors.forename: H Maelor
authors.initials: HM
authors.lastname: Davies
mesh_terms: D002678:Chimera / Q000235:genetics; D018744:DNA, Plant / Q000235:genetics; D051456:Gene Flow; D005838:Genotype; D018525:Germination; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000235:genetics; D006824:Hybridization, Genetic; D058634:Molecular Farming / Q000379:methods*; D010641:Phenotype; D030821:Plants, Genetically Modified / Q000737:chemistry / Q000235:genetics; D011058:Pollen / Q000502:physiology; D014026:Nicotiana / Q000737:chemistry* / Q000235:genetics*; D019076:Transgenes
chemical_list: D018744:DNA, Plant; D049452:Green Fluorescent Proteins
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