Syngenta comes to the rescue to keep the transgenic treadmill going Prof. Joe Cummins
One major impact of crops genetically modified (GM) for insect resistance is that the Bacillus thuringiensis (Bt) Cry toxins conferring insect resistance are specific for particular pests. After the Bt crops have been planted for several years, the target pest is usually diminished, leaving an ecological niche into which another insect pest species may invade. This has already happened with Bt cotton in India  (Mealy Bug Plagues Bt Cotton in India and Pakistan, SiS 45) and in the United Stated, where the tarnished plant bug has emerged as the major pest in the cotton belt  (GM Crops Facing Meltdown in the USA, SiS 46).
Now Christoph Then of Test Biotech, an independent German research group, reports on the spread of the western bean cutworm (Striacosta albicosta) and the massive damage inflicted on Bt maize in the United States : “The infestation has been observed since the year 2000.…. This cutworm has historically been confined to very limited regions and did not cause any major problems in maize crops. For several years now the pest has been spreading into more and more regions within the US Corn Belt and causing substantial economic damage. In 2009, maize plants affected by the western bean cutworm were even found in Canada for the first time. According to scientific publications, this new pest has been caused by the large-scale cultivation of genetically engineered plants expressing Cry1Ab such as MON810. It is seen as a case of 'pest replacement', often found where there is extensive use of pesticides in industrial agriculture. Pest replacement means that new ecological niches open up which other competitors then occupy. In this case, a naturally occurring competitor of the western bean cutworm has been intentionally suppressed by the extensive cultivation of Bt maize plants, thus allowing the new pest to spread on a large scale and heavily infest the crop. A whole arsenal of insecticides - some of them highly toxic - and genetically engineered multi-stacked maize are recommended for controlling the pest.”
For the most part, the pesticides used to combat new pests are toxic, expensive and leave residues on food and feed. The Bt Cry toxins available for genetic modification have not proven sufficiently effective against the newly emerged pest. Syngenta Corporation was quick to fill the pesticide gap by introducing a maize line called Agrisure Viptera to control western bean cutworm. That GM maize line is derived from event MIR162 incorporating a Bt vegetative insecticidal protein, VIP3Aa . VIP toxins are produced in growing Bt cells as distinct from the Cry toxins that are produced as crystals in stationary stage sporulating Bt cells. Agrisure Viptera was cleared for commercial release by USDA/APHIS and USEPA in time for the growing season in 2010.
Event MIR162’s Bt insecticidal vegetative protein gene vip3Aa20 is driven by a maize polyubiquitin promoter with the CaMV 35S 3’ polyadenylation termination signal. A selectable marker pmi encoding mannose-6-phosphate isomerise from E. coli, also driven by the maize polyubiquitin promoter, with Agrobacterium nopaline synthase terminator. The phosphomannose-isomerase converts mannose-6-phosphate to fructose-6-phosphate. Only transformed cells are capable of utilizing mannose as a carbon source. Transgenic plants regenerated from selected transformed immature embryo-derived calli contained the pmi gene and the gene was transmitted to the progeny in ‘Mendelian’ fashion . (This is based on the statistical misuse of failure to depart from ‘Mendelian ratios’ as evidence of transgene stability, as pointed out by ISIS  GM Rice Unstable (isisnews 9/10). The Syngenta petition for non-regulated status of MIR162 maize was an extensive document describing the construction of the transgenic maize line and its field testing for productivity and resistance to pests. VIP3Aa20 produces pores in the gut cell membrane of insect pests that caused the cells to burst; its target cell proteins are different from those of the Cry proteins. The impact of MIR163 on non target organisms were examined, but only with the VIP3Aa20 protein produced in the bacterium E coli, which is different from that expressed in the transgenic maize. The latter is transcribed from a DNA sequence that had been altered to optimise production of VIP3Aa20 protein in maize, differing by several amino acids, but assumed, unjustifiably, to be insignificant .
In 2005, USDA/APHIS determined that Syngenta Corporation cotton event COT102 with transgene VIP3A was no longer regulated, and is now used to control a number of Lepidopteron pests [8, 9].
Syngenta corporation, producer of chemical and biological pesticides, has patented the vip genes for use in transgenic crop plants and microbes . The patent provided evidence that Vip3A toxin produces apoptotic cell death, a series of cytological changes including the production of membrane bound apoptotic bodies and activation of endonuclease enzymes that cleave chromatin into discrete fragments. Apoptosis (meaning petals falling from a flower) or programmed cell death, is common to all cells with discrete nuclei. Apoptosis is a part of normal development, but that induced by VIPp3A toxin is not. In order to function fully in the plant cells the vip3A gene is modified in its coding sequence, and is given additional extraneous sequences: a strong promoter to drive transcription, an intron to facilitate transfer of the pre-messenger RNA from nucleus to cytoplasm, a transcription terminator, and signal for polyA addition. The insect VIP3A receptor was identified and its ‘death domain’ recognition sequence characterized. Organisms whose cells have nuclei generally have families of receptors with ‘death domain’ recognition sequences, just as the insect VIP3A receptor is a unique member of a family of receptors [11, 12]. The death domain of VIP proteins is a 60 to 70 amino-acid motif, that is present in many proteins and phylogenetically conserved, as I pointed out previously  (Death Domains in New Bio-pesticides, SiS 26). The effects of VIP proteins on non-target organisms need to be very thoroughly investigated. USDA /APHIS finding of no significant impact (FONSI) has allowed the unconfined cultivation and use of COT102. The environmental assessment responded to public comment about apoptosis, but did not discuss the topic extensively .
Syngnta seems to have quickly turned adversity into opportunity. Nevertheless, once the western bean cutworm occupied niche is subdued, another resistant pest will appear to provide further opportunity for enriching biotech corporations in the endless transgenic treadmill  (see Glyphosate Resistance in Weeds - The Transgenic Treadmill, SiS 46).
The only escape from the transgenic meltdown may well be organic cropping .
Article first published 14/04/10
Got something to say about this page? Comment
There are 3 comments on this article so far. Add your comment above.
joe cummins Comment left 16th April 2010 05:05:05
In reply to the comments from Karen Midwood: Your questions and answer are welcome. However, we still nave voices that will be heard and have good impact on governments.Organic food is an answer so long as we demand that the food be kept clean of gene pollution from GM crops, GM bio pharmacueticals and and industrial chemicals produced in food crops.
Dr. I.S. Perlingieri Comment left 18th April 2010 14:02:56
17 April 2010 The corporate-controlled mass media continues routinely to given US citizens Orwellian doublespeak. In a New York Times article (in the business section) this week, Andrew Pollack wrote an article called "Study Finds Benefits in Genetically Modified Crops But Warns of Overuse" [April 14, 2010 page B3]. The newspaper also posted it online [in their Business/Energy & Environment section] at: http://www.nytimes.com/2010/04/14/business/energy-environment/14crop.html?scp=1&sq=study%20finds%20benefits%20in%20genetically%20modified%20crops&st=cse Any opposition to the continued poisoning of crops, the soil, and all living animals (with humans at the top of a toxic food chain) is discredited or ignored. The corporate history of deliberate environmental contamination is long and sordid. Independent US scientists are rare. The only way this global poisoning can stop is by a concerted grassroots movement of consumers refusing to purchase any GM products. The buck really does stop at the cash register. Our well being and safety are not part of the corporate bottom line. The only things about which they are concerned are their greed and out-of-control profits --at any and all cost. We continue to be expendable for their bottom line. I applaud ISIS for continuing its urgently needed and invaluable international role in alerting us to the on-going extreme dangers of GM crops and foods. Dr. I.S. Perlingieri author: "The Uterine Crisis"
Karen Midwood Comment left 15th April 2010 05:05:14
What a nightmare! How do we stop these insame mad scientists from further polluting our food chain. And what exactly will prevent a chemical that cause cells to die from affecting humans? I take it they are no longer required to do testing to answer this question because of the lame FDA's GRAS list here in the USA and the equiv. government agencys in the UK etc. Next they will come after the individual citizens right to grow and consume organically grown produce. Where will it end? Is there anyway to stop them. Between the evil Monsanto and the FDA irridation of more and more foods...AND owning the organic lable right. I fear that humanity is not going to go into the future in good health. It's an all out assult on our right to choose. And these evildoers and just the puppets of the real powers that be. The WHO, United Nations and the shadow people controlling them want us to die. So more will be left for them. Are they really so arogant as to believe that they will be able to contain the franken foods they are creating? Guess I just answered my own question. How very sad.