The natural transformation of the soil bacteria Pseudomonas stutzeri and Acinetobacter sp by transgenic plant DNA strictly depends on homologous sequences in the recipient cells

The npt11(+) gene present in the genome of transgenic potato plants transfo rms naturally competent cells of the soil bacteria Pseudomonas stutzeri and Acinetobacter BD413 (both harboring a plasmid with an nptII gene containin g a small deletion) with the same high efficiency as nptII(+) genes on plas mid DNA (3 x 10(-50)-1 x 10(-4) transformants per nptII(+)) despite the pre sence of a more than 10(6)-fold excess of plant DNA. However. in the absenc e of homologous sequences in the recipient cells the transformation by nptI I(+) dropped by at least about 10(8)-fold in P. stutzeri and 10(9)-fold in Acinetobacter resulting in the latter strain in less than or equal to 1 x 1 0(-1)? transformants per nptII(+). This indicated a very low probability of non-homologous DNA fragments to be integrated by illegitimate recombinatio n events during transformation. (C) 2001 Federation of European Microbiolog ical Societies. Published by Elsevier Science B.V. All rights reserved.