GM pea study discontinued after assessment failure
By Anthony Fletcher
21/11/2005- Research to genetically modify peas to resist insect attack
and reduce the use of chemical sprays has been discontinued after the failure
of a stringent risk assessment.
The
GM field peas, developed by the Commonwealth Scientific and Industrial Research
Organisation (CSIRO) to protect Australia's $100 million field pea industry
from the pea weevil Bruchus pisorum, which can cause yield losses of
up to 30 per cent each year if left uncontrolled, proved almost 100 per cent
effective against attacks.
However,
research led by immunologists Dr Simon Hogan and Professor Paul Foster at the
John Curtin School of Medical Research (JCSMR) showed that the GM peas caused
an immune response in mice.
Following discussions with the scientists conducting the study, CSIRO decided
not to progress development of these GM field peas.
"This work
strongly supports the need for case-by-case examination of plants developed using genetic
modification and the importance of decision-making
based on good science, " said deputy chief of CSIRO Plant Industry, Dr
TJ Higgins.
"Even though
this GM field pea research will not be progressed further, the technology is very valuable and we're
considering applying it to other research. "
Gm crops still divides opinion, nowhere more so than in Europe. The
Commission has, to date, asked EU members over ten times to vote on authorising
a GMO food or feed product, but in the large majority of cases, there was no
agreement or simple deadlock.
Countries including the US and Australia on the other hand have historically
been more receptive to the possibilities of genetically modified technology.
The CSIRO research team used a gene from beans to block the activity of alpha-amylase,
an enzyme important for digestion of starch. Weevil larvae feeding on starch in
the developing pea seed are unable to digest the starch and starve.
"We asked why
there was a reaction to
the GM peas and not beans, which also have the alpha-amylase inhibitor, and
which humans have been eating for many years without evidence of an
immune response, " said Foster.
The answer lay in subtle changes that occurred in the chemical structure of the
bean alpha-amylase inhibitor when it was made in the field pea.
"The change in structure is likely to be caused by a
natural and commonly occurring process called glycosylation, which
occurs when proteins
are made via a particular pathway in cells, " said Foster.
"CSIRO had informed us that unlike other GM insect resistant plants, to make the peas insect resistant
the introduced bean protein had to go through a pathway in cells where it
would undergo several processing steps including glycosylation.
"Because glycosylation is well documented and because it can differ
from organism to organism and even in different cell types within an
organism, we determined the structure of the pea protein, and
assessed whether it was likely to cause an immune response.
"
The findings were published in last week's Journal of Agricultural
and Food Chemistry. CSIRO is now finalising arrangements with the Office of
the Gene Technology Regulator for the disposal ofGM field peas produced during the
project.