'Frankenfood' Revolution Stalls

by Peter N. Spotts
The Christian Science Monitor August 15, 2005

It's the kind of breakthrough scientists often dream about.

They have unraveled the complete genetic blueprint for rice — the staple for more than half of the world's population. The development — a key to future genetic blueprints for other cereals and grains — should make it far easier to engineer better, more nutritious crops that could trigger a second "green revolution," whose predecessor — using more traditional farming and breeding approaches — is said to be running out of gas.

There's just one problem. It's not clear the world is ready for another food revolution if it involves splicing foreign genes into crops.

"The initial expectation that this technology would be rapidly adopted turned out to be a bit optimistic," says Michael Rodemeyer, executive director of the Pew Initiative on Food and Biotechnology. "We're in a stall in the development of new GM foods."

To be sure, farmers are producing more bioengineered crops every year. Farmers have found many of these genetically modified crops quite useful. GM soybeans are cheaper to grow; GM papaya has saved Hawaiian growers from a virus that had made their traditional crop unmarketable. But these remain first-generation GM varieties with only indirect consumer benefits.

The next generation — offering consumers better-tasting, more nutritious, or longer-lasting food — is taking longer than the industry's optimists expected, Rodemeyer adds.

The reasons are legion, analysts say.

Outside the United States, public reluctance and activist campaigns citing everything from environmental concerns to the extensive clout of multinational corporations have slowed the introduction of GM crops. This resistance led Monsanto last year to shelve the first commercially available genetically engineered wheat. U.S. wheat growers worried that GM-wary global customers would buy elsewhere.

Within the U.S., where farmers plant more than 167 million acres of GM crops, public unease has been less evident. But some analysts expect that to change as companies genetically engineer crops to make them more nutritious or harness crops to produce compounds for drugs.

Second-generation GM crops also pose a tougher scientific challenge than the first-generation did. The traits researchers want to enhance are likely to involve several genes and complex interactions between the plant and its environment.

In this political and scientific environment, rice is poised to become the latest "crop célèbre" in the ongoing debate over conventional and genetic-engineering approaches to feeding the world.

The new rice genome, pulled together by researchers worldwide under the umbrella of the International Rice Genome Sequencing Project, was completed three years ahead of schedule. Researchers say much of the credit for the speed goes to Monsanto for making available the rice data it had. Scientists picked rice as the first cereal crop to sequence because of its genome's relative simplicity. Other, more complex cereals share rice's genes, often in the same positions in long DNA assemblies known as chromosomes. Thus, rice has the potential to become a Rosetta stone for reading other key cereal genomes.

"That's one of the exciting aspects" about having the rice genome in hand, says Sally Leong, a research chemist with the U.S. Department of Agriculture's Agricultural Research Service lab in Madison, Wis. And the international nature of the project has helped build capabilities within some key developing countries.

Now comes the tricky part, scientifically associating the genes or gene combinations with specific plant traits and processes. As that information becomes available, traditional breeders can use it to identify useful genes and then trace their movement through several generations. By using seedlings alone, researchers speed up traditional breeding. Rice genetically engineered by inserting foreign genes, however, may face a tougher challenge.

Several charitable foundations and international research institutes are working to enhance the level of "micro- nutrients" — trace minerals such as zinc and iron — as well as vitamin A in rice. The enhanced rice could help in the fight against malnutrition.

Yet golden rice so far has languished, partly because of environmental concerns. Some of the countries that could most benefit have imposed regulatory barriers that are too costly for the public project, says Jorge Mayer, golden-rice project manager at the University of Freiburg, Germany.

In the U.S., meanwhile, a California biotech company proposing to grow GM rice on a 200-acre plot in Missouri was sent packing in April. The rice had been modified to produce two synthetic human proteins for pharmaceuticals. Anheuser-Busch, worried about contamination of conventional rice, threatened to boycott all Missouri-grown rice used in its brewing activities if the project was approved.

In the quest to ease global malnutrition, too much emphasis is being placed on genetic engineering without a sufficient look at the risks and alternatives, says Doreen Stabinsky, a geneticist by training who serves as a science adviser to Greenpeace. "We need a realistic assessment of what the technology can and can't do."

Scientists Warn of GM Superweed Risk

By Paul Brown
The Guardian
August 18, 2005

Scientists have identified 15 weed species that are resistant to a herbicide widely used on GM crops and are warning farmers they may become a serious problem unless a strategy for dealing with them is developed.

Some of the most common weed species, including types of ryegrass, bindweed and goosegrass either have some strains with a natural resistance to the widely used GM herbicide glyphosate or have developed one.

Writing in the journal Outlooks on Pest Management, four scientists argue there is a danger that by ignoring the threat these weeds pose, farmers may be giving them a huge advantage over other plants which are killed by glyphosate.

Even where they did not previously thrive on farmland or were in a minority of weeds, farmers may be creating a new niche for them among arable crops which would allow them to multiply rapidly.

The paper is published alongside an assessment of the three-year farm-scale trials of GM oilseed rape, sugar beet and maize in Britain. All three crops are glyphosate-resistant and, if the American researchers are right, would be troubled by glyphosate-resistant weeds if grown commercially in the UK.

Glyphosate has been used by farmers to kill off weeds for 30 years but since the 1990s, when GM crops were modified to resist glyphosate, its use has mushroomed.

The paper says that worldwide use has increased from 5,000 tonnes a year in 1995 to more than 30,000 tonnes in 2002, and has increased since.

However, intensive use of the herbicide combined with the non-rotation of glyphosate-resistant GM crops is expected to increase the problem and it will develop on "a global scale," the paper says.

The researchers, based at the State University and the Southern Weed Research Unit in Mississippi, are concerned that the widespread usefulness of an extremely efficient weedkiller will be lost if farmers do not take precautions.

"The problem of glyphosate-resistant weeds is real, and farmers have to realise that the continuous use of glyphosate without alternative strategies will likely result in the evolution of more glyphosate-resistant weeds.

"Even in the short term no one can predict the future loss of glyphosate efficiency due to weed species shifts and evolution of glyphosate resistance," says Vijay Nandula in the conclusion to the paper.

He advises farmers to treat land with additional herbicide to kill off the weeds before they multiply sufficiently to cause a problem.

Field-testing Bacterial Pathogens with Antibiotic Resistance Genes

By Prof. Joe Cummins
August 20, 2005

The University of Wisconsin is preparing to release genetically modified (GM) Erwinia carotovora bacteria containing antibiotic resistance marker genes in environmental field tests. The United States department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has prepared a docket with background information on the release and there is a public comment period ending 15 September 2005 [1]. The tests are to be conducted at the University of Wisconsin Experiment Station near Hancock, Wisconsin. The environmental release of bacterial strains each containing a different antibiotic should be a matter of grave concern and a strong public response is in order.

The purpose of the field trial seems to be simply experimental with no potential commercial application of the genetically modified bacteria. Erwinia carotovora causes a rot disease in potatoes. The experiment is designed to test the fitness of bacteria that have had genes known to be associated with pathogenesis that have been disrupted by inserting in those genes the antibiotic resistance genes. The antibiotic resistance genes not only eliminate the function of the pathogenesis gene but they also serve as selectable markers to identify the modified bacteria. The antibiotic resistance genes are precisely inserted into the target pathogenesis gene by adding short DNA tails to the resistance genes that are homologous to the target pathogenesis gene. The pathogenesis gene targeted is hrp, which controls secretion of virulence proteins into the host plant. Green fluorescence protein was inserted as a visual marker to identify potatoes with the modified bacteria [2].

The field test involves four GM mutant strains, WPP60, WPP198, WPP195 and WPP40. WPP60 was created by inserting the streptomycin/spectomycin genes into the hrpC, while WPP98 had chloramphenicol resistance gene inserted into hrpL. WPP195 was created by deleting the hrpN gene and inserting the choramphenicol resistance gene in its place. WPP40 has the kanamycin resistance gene inserted into the outD gene required for protein secretion, so it cannot secrete plant cell-wall degrading enzymes. Inserting antibiotic resistance genes into the hrp genes interferes with pathogenesis. However, only strain WPP40 that inactivates the outD gene is reduced in virulence in a direct assay, nevertheless, the researchers decided to carry out the field experiment [2].

They claim that the field tests are not expected to impact agricultural practice because "the test is solely for research purposes" even though Erwinia carotovora affects potato, cucumber, capsicum, turnip, brussel sprouts, carrots and celery, all of which are grown in the general area of the test site. Because the antibiotic resistance genes are not being selected by antibiotic application, they are not deemed to be a cause for concern, according to the applicants. The proposal believes that the antibiotic resistance genes cannot be transferred to bacteria affecting humans; justifying that position by referring to the US Food and Drug Administration’s judgment that antibiotic resistance is already prevalent in bacteria affecting humans and in soil-borne bacteria. Even though the soil is sandy and porous in the test site, the applicants claim that the spread of the GM bacteria is not expected, nor has it been tested for [2]. In general, the application focuses on the benefits of the experiments and ignores any evidence that might delay the experiment. Apart from the release of antibiotic resistance genes, the most obvious question is why release so many strains that are genetically modified as well as still virulent? That procedure provides high risk with little or no benefit.

The belief expressed in the proposal, that GM Erwinia carotovora would not transfer antibiotic resistance genes to other soil bacteria, is inconsistent with the scientific literature. Horizontal gene transfer is commonplace in Erwinia and Klebsiella and transfer could extend to Salmonella, Shigella and E. coli [3]. The GM bacteria contaminating surfaces of food crops may also transfer antibiotic resistance gene to enteric bacteria when ingested by humans or animals. Bacteria phage were found to transfer genes between Erwinia species [4]. Transposons capable of mobilizing antibiotic resistance genes have been identified in Erwinia carotovora [5]. There is thus clear evidence that Erwinia is capable of moving resistance genes among soil Erwinia species, between other soil bacterial species and among enteric bacteria.

A number of GM microbes bearing antibiotic resistance markers have been released commercially in the United States, these include Sinorhizobium, Agrobacterium and Psuedomonas [6]. Little effort appears to have been made to monitor the consequences of these releases. Mae-Wan Ho has discussed the hazards of horizontal gene transfer in some detail [7, 8].

The main problem with the proposed field test of GM Erwinia carotovara is the failure to monitor the spread of the modified bacteria and the horizontal spread of transgenes. The release of virulent GM Erwinia does not appear to provide any benefit that would justify the risks of spreading the antibiotic genes.

This article has been submitted to the US EPA on behalf of the Independent Science Panel. Please add your support by registering your opposition in the docket by referring to this article.

Reference

Field-testing GM Fungus

By Prof. Joe Cummins
August 20, 2005

The University of Kentucky has prepared Environmental Assessment for Field Tests of Genetically Engineered Neotyphodium, an endophyte fungus living inside ryegrass. USDA/APHIS has prepared a docket, which is available for comment until12 September 2005 [1]. Fungal endophytes live symbiotically inside plants without harming them. The fungus grows in or around plant cells in a cozy relationship whereby the plant feeds the fungus, which takes what it is given and no more to avoid becoming a parasite on the plant. The fungus Neotyphhodium provides rye grass with alkaloids that protect the plant from animal predators. The grass bearing the endophyte has a clear advantage over grass lacking the fungus. However, alkaloids such as the ergot family adversely affect grazing mammals. The fungus reproduces asexually in the grass and does not produce sexual spores. However, fungi have active mitotic recombination and somatic gene conversion in what is called a "para sexual cycle". The fungus is passed through the maternal tissue to the seed, and inoculation of a plant lacking the fungus is difficult.

The proposed release involves two different strains modified in different genes for alkaloid formation. One of the transgenic endophytes has a gene for dimethylallytryptophan synthase (dmaW) disrupted, the other has a gene for lysergyl peptide synthetase (IpsA) disrupted. The disrupted dmaW eliminated production of the alkaloid ergovaline and its precursors including lysergic acid. Disrupted lpsA eliminated ergovaline, but not lysergic acid. In that strain, lysergic acid increases markedly about twenty five times. Both transgenic strains were disrupted by introducing the hygomycin B phosphotransferase (hph) gene from a bacterium into the dmaW and lpsA genes. The hph confers antibiotic resistance and is driven by a promoter from the fungus Neurospora and a transcription terminator from the fungus Aspergillus. The hph genes are targeted specifically to disrupt the dmaW and lpsA genes by adding short DNA sequences from the target gene at both ends of the hph insert [2- 4].

In the proposal, the inserted antibiotic resistance gene is assumed to have no impact on the growth of the endophyte in the absence of antibiotic treatment, but evidence in support of that assumption was not provided. Furthermore, gene disruption leads to "pop out" in some fungi - an intra-chromosomal homologous recombination that splices out the inserted gene, mobilizing the excised insert as a circular DNA unit and restoring the disrupted gene to full activity. This possibility seems not to have been considered in the proposal.

The proposal claims that the fungal endophyte and its antibiotic resistance gene will be stable and not be transmitted horizontally. There was little or no discussion of the potential impact of the protein produced by the antibiotic resistance gene, hygromycin B phosphotransferase, other than to note the United States Environmental Protection agency had granted it an exemption from tolerance. Exemption from tolerance means that any level of the exempt protein is deemed to be safe and acceptable and allowed in food and feed. The toxicity and allergenicity of the protein does not appear to have been considered in the proposal. The proposal argues that there will be little or no horizontal transfer of the resistance marker but does not allow for the fact that the grass carrying the transgenic endophyte is bound to breakdown. In that eventuality, antibiotic resistance gene will be released to the soil environment where it may transform soil bacteria. Furthermore, transformation of gut bacteria may also occur during digestion of the grass by the pasture animals.

GM endophytes have previously been tested. A bacterial endophyte of yellow lupine was modified with genes for degrading an organic pollutant along with genes for antibiotic and nickel resistance. The bacterial enodphyte turned out to be a pathogen for humans! As in the present proposal, little concern was given to the spread of antibiotic genes in the environment [5].

The proposal to field test GM endophyte modified pasture grass should have been preceded by feeding experiment with the modified grass. The animals should be examined by a full necropsy to study the impact of the grass. The fate of the introduced antibiotic resistance gene in decaying and fed modified grass should be examined. All those experiments should at least be undertaken before open field tests are contemplated.

This article has been submitted to the USDA/APHIS on behalf of the Independent Science Panel. Please add your support by registering your opposition in the docket by referring to this article.

References

Bt Maize Inferior Yield

By B.L. Ma and K.D. Subedi
Field Crops Research 93: 199*211
August 18, 2005

Development, yield, grain moisture and nitrogen uptake of Bt corn hybrids and their conventional near-isolines.

ABSTRACT

There are concerns over the economic benefits of corn (Zea mays L.) hybrids with the Bt trait transferred from Bacillus thuringiensis. A field experiment including three to seven pairs of commercial hybrids and their transgenic Bt near-isolines were grown side-by-side for three consecutive years in Ottawa, Canada (458170N, 758450W; 93 m above sea level) to determine (i) which hybrid had the highest yielding potential, (ii) if there was a differential response of Bt and non-Bt hybrids to N application, and (iii) under natural infestation of European corn borer (ECB), whether there was a yield advantage of Bt over non-Bt hybrids to justify their cost.

We found that some of the Bt hybrids took 2*3 additional days to reach silking and maturity, and produced a similar or up to 12% lower grain yields with 3*5% higher grain moisture at maturity, in comparison with their non-Bt counterpart.

Although N application increased grain yield and N uptake in 2 of the 3 years, there was no N-by-hybrid interaction on yield or other agronomic traits. Most Bt hybrids had similar to or lower total N content in grain with higher N in stover than their respective non-Bt near-isolines. Under extreme weather conditions (e.g. cool air temperature at planting and severe drought during the development), some of the hybrids (both Bt and non-Bt) required up to 400 additional crop heat units (CHU) to reach physiological maturity than indicated by the supplying companies. Our data suggest that within the same maturity group, it was the superior hybrids (non-Bt trait) that led to the greatest N accumulation, and the highest grain yield. Under the conditions tested, there was no yield advantage of Bt hybrids in comparison with their conventional counterparts when stalk lodging and breakage of the non-Bt counterpart by ECB was low to moderate.

http://www.gmwatch.org/archive2.asp?arcid=5620

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