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[SANET-MG] vistive soy



October 9, 2004

Prof. Joe cummins

“Vistive soybeans with low linolinic oil”

In Sept. 2004 Monsanto announced that Vistive soybean with reduced
linolenic (low linolenic or LL) acid content will be available for
planting in the 2005 season. Vistive includes genes reducing the oil
content of linolenic acid and transgenes conferring roundup ready trait.
Vistive soy does not appear to have been approved by the procedure
employed with transgenic crops because the reduced linolenic acid
content was achieved using traditional selection and breeding. It
appears that government regulators assumed that the roundup ready trait
acts independently of the LL trait and for that reason the two kinds of
traits could be joined by crossing two strains. Certainly the there is
no precedent for reviewing and approving crops produced by conventional
breeding but if the LL trait interacts with the roundup ready
(glyphosate resistance) trait the Vistive strain should be re-reviewed
as an alteration in the original roundup ready trait. There is a clear
indication that the use of glyphosate on the soybean crop will result in
an impact on fatty acid metabolism through the breakdown products of the
herbicide and that process will be discussed after a fuller description
of the Vistive trait is provided.

Vistive soybeans with the roundup ready trait are claimed to contain
less than 3% linolenic oil, in contrast to the 8% linolenic content for
conventional soy oil. Low linolenic oil is more stable, with a better
flavor and requires less hydrogenation. Trans fatty acids are produced
in the hydrogenation process , the trans fatty acids are linked to hear
disease because they lower HDL (good) cholesterol while raising LDL
(bad) cholesterol (1). Ironically, trans fats labeling is to begin in
2006 in the United States even though labeling of products containing
transgenes is resisted by industry and regulators in the United States.

In plants fatty acids are produced in the chloroplasts. Two molecules
are crucial for fatty acid synthesis these are acetyl-CoA and
malonly-CoA (acetyl-CoA with an added carbon dioxide molecule).The
number of carbon atoms in the long fatty acid chain is always even the
carbon molecules are added two at a time. The newly synthesized fatty
acids may be altered in mitochondria or endoplasmic reticulum or stored
in membrane bound lipid vesicles. Catabolism of the fats is undertaken
in organelles called glyoxysomes where the fatty acids are degraded two
carbon at a time by a process called beta oxidation (2). Fatty acids are
modified in organelles and endoplasmic reticulum by the lipoxygenase
pathway to produce plant defense and signaling compounds such as
jasmonates (3). Glyoxysomes carry on the glyoxylate cycle a modification
of the tricarboxylic acid cycle that is found in plants and microbes as
well as beta oxidation (4). Fatty acid metabolism is crucial to energy
maintenance in plants but as well contributes to cell structure and to
signaling and defence.

The transgenic parent of Vistive soybean was the soybean line GTS40-3-2
(event MON-04032-6) resistant to glyphosate. The strain was released to
the environment in the United States in 1994,Canada 1995,Japan
1996,Aregentina 1996,Uruguay 1997,Mexico 1998,Brazil 1998 and South
Africa 2001(5). The construction includes a synthetic approximation
EPSPS gene from Agrobacterium for tolerance to glyphosate, sequence of
the EPSPS gene was adjusted for the codon preference of the crop. The
EPSPS gene was driven by the enhanced 35s cauliflower mosaic virus
promoter, the sequence included a chloroplast transit protein from
petunia and a nopaline synthesis terminator from Agrobacterium. (5,6).
Six years after roundup ready soy was released to the environment
Monsanto acknowledged that “inactive” 75 base pair fragment and a 250
base pair fragment of the EPSPS gene were inserted outside the open
reading frame of the EPSPS protein (those inserts were over 20% the size
of the EPSPS gene (7). The origin of the gene fragments and their
possible activity was curtly dismissed without fuller explanation. The
evident instability of these and other crop transgenes has been
discussed by MaeWan Ho (8,9).

Returning to the possible interaction between the LL and roundup ready
genes of Vistive soy , the crop will certainly be sprayed with
glyphosate. The herbicide would accumulate to levels toxic to animals
and humans if it was not broken down in the plant cell. In plants
glyphosate is broken down by glyphosate oxidase enzyme (presumably an
enzyme present to digest natural products). Glyphosate oxidase (GOX)
enzyme accelerates the breakdown of the herbicide glyphosate into two
compounds, aminomethylphosphonic acid (AMPA) and glyoxylate. Glyoxylate
is commonly found in plant cells and is broken down by the glyoxylic
pathway for lipid metabolism. The rush of glyoxylate would certainly
disrupt the metabolism of fatty acids. Glyphosate exposure of herbicide
tolerant groundnut was observed to glyoxylase enzyme (10). Presently it
is not possible to predict the nature and extent of disruption of fatty
acid metabolism nor the impact on LL function. The point, here, is that
there is a clear link between roundup ready and LL traits that should be
explored fully before the Vistive crop reaches general distribution. It
seem very thoughtless of regulators to allow release of the crop. Every
transgenic release should be reassessed after it has been crossed with a
derived from selection that has a clear metabolic association with the
transgene.There should be a rule to insure that careful reassessment is
done.

Finally, it may be needless to say that the burden of proving releases
such as Vistive to be safe rests with the proponent, experiments must be
done to insure that the roundup ready genes and the LL genes are truly
independent of each other.

References

1.Monsanto Monsanto Launches VISTIVE™ Soybeans; Will Provide a Trans
Fats Solution for the Food Industry 2004
http://www.monsanto.com/monsanto/layout/media/

2, Botany on line: Basic Metabolism-Biosynthesis-Lipids Lipids 2004

http://www.biologie.uni-hamburg.de/b-online/e19/19i.htm

3.Feusner,I and Wasternack,C The lipogenase pathway 2002 Ann Rev Plant
Biol 53,275-97

4. vanden Bosch,H,Schutgens,R,Wanders,R. And Tager,J. Biochemistry of
peroxisomes 1992 Ann Rev Biochem 61,157-97

5. Agbios data base Soybean MON-04032-6 (GTS40-3-2) 2004

http://www.agbios.com/dbase.php?action=ShowProd&data=GTS+40-3-2&frmat=LONG
<http://www.agbios.com/dbase.php?action=ShowProd&data=GTS+40-3-2&frmat=LONG>

6. United States Department of Agriculture/APHIS 93-258-01p Soybean

USDA/APHIS Availability of determination of non-regulated status of
Monsanto genetically engineered soybean line 40-3-2 1994
http://www.aphis.usda.gov/brs/aphisdocs2/93_25801p_com.pdf

7.Monsanto Company Updated Molecular Characterization and Safety
Assessment of Roundup Ready Soybean Event 40-3-2 2000 Confidential
Report MSL-16712 pp1-20

8. Ho,M. Transgenic lines proven unstable 2003 http://www.i-sis.org.uk/

9. Ho,M. Unstable transgenic lines illegal 2003 http://www.i-sis.org.uk/

10. Jain,M,Choudry,D,Kale,R. and Bhalla-Sarin,N. Salt and glyphosate
induced increasers in glyoxylase 1 activity in cell lines of ground nut
(Arachis hypogea) 2002 Physiologia Planterum 1154,499-509

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