Student - November 8, 2007

Bacteria don’t like gm potato genes

The chance that new genes in potato or tomato plants ‘leak’ into other organisms is virtually nil, researchers from Plant Research International (PRI) have concluded. They published the results of their study of more than five hundred bacteria in Environmental Biosafety Research.

Opponents of genetic modification fear that synthetic genes in crops may be taken up by bacteria that live on modified plants. The introduction of new genes in bacteria could lead to ecological and medical dangers. ‘There are bacteria that absorb DNA out of their environment,’ says Dr Leo van Overbeek of PRI. ‘We don’t yet know why they do this, but we know that they absorb DNA from members of the same species more easily than DNA of plants. Bacteria usually break down alien genetic material.’

There are a few bacteria, however, that in theory could absorb genetic material from gm plants. To determine whether these are also found on tomato and potato plants, Overbeek and his colleagues used an EU grant to examine 552 bacteria, all of which at some time have been found on potatoes or tomatoes, to see whether they could absorb alien DNA under laboratory conditions.

The researchers brought the bacteria in contact with genes that create resistance to antibiotics. ‘When we counted how many bacteria had become resistant to the antibiotics, we could only find two isolates that were capable of absorbing the genetic material,’ said Overbeek. Two bacteria out of 552 is very few, but not necessarily proof that new genes do not ‘leak’, says Overbeek. ‘There is a gap between the laboratory and the field. It is possible that something happens in nature which results in bacteria taking up alien DNA more easily.’

The result of his study is typical of research on the risks of gm crops, says Overbeek. ‘As a scientist you can say something about the risks involved in gentech. But to prove that gentech is a hundred percent safe is impossible.’

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