CROP GENE EXPERIMENTS `COULD BREED
SUPERWEEDS'
PA 08.09.98 13:08
Copyright 1998 PA News. Copying, storing, redistribution, retransmission, publication,
transfer or commerical exploitation of this information is expressly forbidden.
By John von Radowitz, PA News
Careless genetic tampering with crop plants to defend them against viruses raises a real
risk of producing "superweeds", a scientist advising the government warned
today.
New research by Professor Alan Gray suggests that making plants resistant to viruses has a
much bigger effect on their survivability than had previously been realised.
Viruses thought to live in peaceful harmony with their plant hosts could actually be
killing them, said Professor Gray.
If such plants were made immune to viral attack there was a danger of them turning into
uncontrollable weeds.
Professor Gray is a member of Acre, the Advisory Committee on Releases to the Environment,
which guides government policy on genetically modified organisms.
His team at the Institute of Terrestrial Ecology at Furzebrook research station, Wareham,
Dorset, discovered a surprising range of viruses in wild cabbages.
Young wild cabbages grown from seed were infected with two of these viruses and planted on
a cliff in Dorset. One called turnip yellow mosaic virus increased the death rate of the
cabbages, and both viruses reduced their reproductive performance.
Professor Gray said the findings challenged the view that plant populations were generally
not greatly affected by viruses. This mistake may have arisen because whole populations
have been wiped out by viruses and were therefore missed by scientists.
Speaking at the British Association Festival of Science at Cardiff University, Professor
Gray said: "The potential is there to end up with a superweed. We've had trials of
virus-resistant plants in the UK."
He said in the United States a virus-resistant squash had already been deregulated and
released into the environment.
Professor Gray said the whole debate about GMOs had been too generalised. He called for
more focus on factual details such as virus resistance.
Professor Gray said: "The question is, is there something in natural populations of
plants that is keeping their abundance down? What I'm saying is in lots of cases we don't
know what the factors are that suppress plants and prevent them becoming weeds.
"The major causes of mortality in various populations are very different for
different plants and different wild species which could get new genes.
"We can't do generic risk assessment for these sorts of genes because we have a long
way to go to understand the role of viruses and other pathogens in regulating plant
populations.
"All of these genes need to be looked at individually and separately. The problem
with this debate is that it's all on a general level and I'm appealing for us to look very
carefully at each example as it comes along."