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2-Plants: GE sugarbeet seeds spread further than expected

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                                  PART I
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TITLE:  GM seeds could beet isolation zones - but they need our help
SOURCE: The Royal Society, UK, Press Release
DATE:   June 18, 2003

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GM seeds could beet isolation zones - but they need our help

One of the potential risks associated with the wider release of genetically
modified crops and their use in mainstream agriculture is the hybridisation
of transgenic plants with their wild relatives. Previous studies on mechanisms
for the escape of transgenic material into the wild population has focused
on pollen dispersal as the main route, but new work by scientists at the
Université de Lille in France to be published in Proceedings B, a Royal Society
scientific journal, highlights the role of seed dispersal - inadvertently
assisted by human activity - in the potential wide scale dispersal of transgenic
material with major implications for the siting of transgenic crops.

Sugar beet

 “Gene flow and interbreeding from cultivated to wild plant populations has
important evolutionary and ecological consequences,” says Dr. Jean-François
Arnaud of the Laboratoire de Génétique et Evolution des Populations Végétales
of Lille University. “This requires detailed investigation to assess the risk
of transgene escapes into natural ecosystems.”

Sugar beets are of particular interest because they are cross compatible
with their wild relatives, for example the sea beet, and crop-to-wild gene flow
is likely to occur via ‘weedy’ hybrid plants locally infesting fields.

“In our study we investigated the potential for ‘escape’ of transgenic
material by analysing a set of molecular markers in a population of weed beets
within a field crop of commercially grown sugar beet, a natural coastal
population of wild sea beet situated over 1.5 km away and a linking ‘contact zone’
along a river where a possible mixture of wild and weedy beets could exist,”
says Dr. Arnaud.

The experiment was conducted in the Wimereux area near Boulogne in Northern

Unexpected result

DNA from samples from plants harvested in the three areas was extracted and
purified and individuals genotyped using height molecular markers to
establish the extent of gene exchange. There was clear evidence of weedy beets
originating from the commercial crop field in the riverside ‘contact zone’ some 1.5
kms away from the field.

“Contrary to classical expectations we found that gene flow through pollen
was limited,” explains Dr. Arnaud. “However we found that weedy beets can act
as a crop-to-wild bridge by escaping from commercial beet fields to wild
populations via accidental seed flow. Our results highlight the likelihood for
transgene escape resulting from seed dispersal events.”

Human culprits

Dr. Arnaud believes that the main mechanisms for seed flow in the studied
area are human activities. “Accidental transport of seeds within soils carried
on motor vehicles, or by other normal agricultural activities is the best
explanation,” says Dr. Arnaud. “Our finding are consistent with the hypothesis
of human-mediated long-distance dispersal.”

“Once wild and weedy beets have been brought close together by seed
dispersal hybridization can occur by subsequent pollen dispersal,” continues Dr.

Two important implications arise from this work. “Firstly it reinforces the
agricultural economic issues caused by increased invasiveness of any future
transgenic weed beets within the agricultural system - originally highlighted
by Benoit Desplanque and colleagues - and secondly it implies that we must be
very cautious regarding the location of transgenic commercial sugar beet
field,” concludes Dr. Arnaud. “If GMO sugar beets are established in regions
where populations of the wild form also occur, then gene flow between wild and
cultivated relatives is almost inevitable.”

 For further information contact:
For more details on this paper, including how to obtain a full copy of the
paper and contact details for the paper’s author, Dr. Jean-Francois Arnaud,
please contact:

Tim Reynolds on tel: or +44 (0) 7711 942974 or +32 (0)2640 3226,

Or email: or

                                  PART II
------------------------------- GENET-news -------------------------------

TITLE:  Humans may spread GM seeds
DATE:   June 18, 2003

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Humans may spread GM seeds

Study suggests intrepid beet weed seeds could spread crop genes into wild

Hitch-hiking on farm machinery, the seeds of sugar-beet weeds can travel
more than a kilometre from the field where they were born. In theory, such seeds
could spread genes from genetically modified (GM) crops into their wild

But the finding, some of the first evidence of gene flow from crops through
seeds, rather than pollen, should not increase worries over the environmental
impact of growing GM foods, researchers say.

"You can't contain genes," says ecologist Alan Gray of the Centre for
Ecology and Hydrology in Dorset, UK. "The concern is to identify possible hazards
from gene flow - we must be very careful about the sort of genes we put in."
Gray chairs the UK government's Advisory Committee on Releases to the
Environment. The study suggests that, in managing GM crops, farming practices will be
as important as technology. To minimize gene flow, domestic and wild beets
need to be well separated, and fields must be carefully weeded.

Cross check

The problem is neither the crops nor the wild plants themselves, but crosses
between the two. Domestic sugar beet breeds with its wild relative, sea beet
(Beta vulgaris ssp. maritima). The resulting hybrids are potent weeds,
producing thousands of seeds in their first year.

These weedy beets' seeds get around, Joel Cuguen of the University of Lille
in France and colleagues have found1. Once the weeds are alongside their wild
relatives, they breed with the wild plants. The researchers DNA
fingerprinted weeds in a sugar-beet field in northern France, and those growing alongside
a river 1.5 kilometres away, where sea beet also grows.

The river weeds were descended from those in the field. They must have been
transported there as seeds - in soil on agricultural equipment, for example,
says Cuguen. "Gene flow through seeds is too often underestimated." "If you
grow beets near the coast, escape is possible," agrees ecologist Detlef
Bartsch of the Robert Koch Institute, Berlin. Gene escape is even more likely in
southern Europe, where the crop is grown for seed, he warns. The
herbicide-tolerant beet varieties being grown in the United States and on trial in Europe
will have no advantage over wild plants - although herbicide-resistant weeds
might give farmers a problem.

But possible future varieties, such as insect- or disease-resistant strains,
might cause environmental damage. "Gene escape will take place - the
question is what the genes are," says Bartsch 


Arnaud, J.-F., Viard, F., Delescluse, M. & Cuguen, J. Evidence for gene flow
via seed dispersal from crop to wild relatives in Beta vulgaris
(Chenopodiaceae): consequences for the release of genetically modified crop species with
weedy lineages. Proceedings of the Royal Society B, published online,
doi:10.1098/rspb.2003.2407 (2003). |Article|



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