Unsuccessful search for DNA transfer from transgenic plants to bacteria in the intestine of the tobacco horn worm, Manduca sexta.

DNA transfer from transgenic plants to native intestinal bacteria and introduced Acinetobacter BD413 was assessed in the gut of the tobacco horn worm (Manduca sexta). The marker was kanamycin resistance gene (nptll), and tobacco carrying the nptll gene in the chloroplasts served as the donor. We detected neither whole gene transfer to native bacteria, nor transfer of fragments of nptll to Acinetobacter, using a marker exchange assay. This negative result was attributed to a heat-labile activity that degraded DNA in the feces, probably DNAase. Nevertheless, a few intact leaf cells survived transit through the gut, and DNA extracted from feces did transform Acinetobacter, albeit at lower frequencies than DNA extracted from leaves.