title: Long-term persistence and bacterial transformation potential of transplastomic plant DNA in soil.
abstract: The long-term physical persistence and biological activity of transplastomic plant DNA (transgenes contained in the chloroplast genome) either purified and added to soil or naturally released by decaying tobacco leaves in soil was determined. Soil microcosms were amended with transplastomic tobacco leaves or purified plant DNA and incubated for up to 4 years. Total DNA was extracted from soil and the number of transgenes (aadA, which confers resistance to both spectinomycin and streptomycin) was quantified by quantitative PCR. The biological activity of these transgenes was assessed by transformation in the bacterial strain Acinetobacter sp. BD413(pBAB2) in vitro. While the proportion of transgenes recovered increased with the increasing amount of transplastomic DNA added, plant DNA was rapidly degraded over time. The number of transgenes recovered decreased about 10,000 fold within 2 weeks. Data reveal, however, that a small fraction of the plant DNA escaped degradation. Transgene sequences were still detected after 4 years and transformation assays showed that extracted DNA remained biologically active and could still transform competent cells of Acinetobacter sp. BD413(pBAB2). The approach presented here quantified the number of transgenes (based on quantitative PCR of 50% of the gene) released and persisting in the environment over time and provided new insights into the fate of transgenic plant DNA in soil.
authors.affiliation: Environmental Microbial Genomics Group, Laboratoire Ampère, Ecole Centrale de Lyon, Université de Lyon, 69134 Ecully, France.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pontiroli
authors.forename: Maria-Teresa
authors.initials: MT
authors.lastname: Ceccherini
authors.forename: John
authors.initials: J
authors.lastname: Poté
authors.forename: Walter
authors.initials: W
authors.lastname: Wildi
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Kay
authors.forename: Paolo
authors.initials: P
authors.lastname: Nannipieri
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Vogel
authors.forename: Pascal
authors.initials: P
authors.lastname: Simonet
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Monier
mesh_terms: D000150:Acinetobacter / Q000235:genetics / Q000378:metabolism; D001419:Bacteria / Q000235:genetics; D001483:Base Sequence; D002736:Chloroplasts / Q000235:genetics; D004247:DNA; D004269:DNA, Bacterial; D018742:DNA, Chloroplast / Q000235:genetics*; D022761:Gene Transfer, Horizontal; D054628:Genome, Chloroplast; D018515:Plant Leaves / Q000235:genetics; D030821:Plants, Genetically Modified / Q000235:genetics; D010957:Plasmids / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012987:Soil / Q000032:analysis; D012988:Soil Microbiology; D014026:Nicotiana / Q000235:genetics; D014169:Transformation, Bacterial; D019076:Transgenes
chemical_list: D004269:DNA, Bacterial; D018742:DNA, Chloroplast; D012987:Soil; D004247:DNA