RCGM Witness Brief Neil Macgregor

Publications & Resources

Witness Brief Royal Commission on Genetic Modification

1. Contact Information: A Neil Macgregor, Institute of Natural Resources, Private Bag, Massey University, Palmerston North.

4. Name of Witness: My name is Neil Macgregor, a biological scientist with primary expertise in soil biology and biochemistry, soil microbial ecology, and microbial genetics. I graduated BSc and MSc from the University of Otago (NZ) and PhD from Cornell University (USA). I have relevant research experience in soil biological processes in land-use systems including nitrogen fixation in both terrestrial and aquatic natural environments, land disposal of rural and urban waste streams, soil and water quality, and the experimental use of reporter genes in microbial ecology studies. I am author/co-author of 70 refereed publications and conference papers. I have held both teaching and/or research positions at Cornell University, University of Arizona (Tucson), University of Wisconsin (Madison), International Atomic Energy Agency (Austria), Institut National de la Recherche Agronomique (France), and Massey University (Palmerston North campus). Recently, I contributed a chapter (“Footprints of Genetic Engineering in Agriculture”) to Designer Genes and have frequently been invited to speak to community groups on effects of GE-crops on soil biology, and future soil research in the organic and vermiculture industries.

5. Name of “Interested Person” (on behalf of whom the Witness will appear): Physicians and Scientists for Responsible Genetics - Charitable Trust (PSRG)

6. Witness Brief Executive Summary

Summary: An important and persistently neglected component of natural and farming-systems inevitably reflecting the effects of farming transgenic forms of plants, animals, and microrganisms, is the soil. For harvested ecosystems, such as agriculture, horticulture, and forestry, soil is not only the very medium supporting production but also the repository of both urban and rural wastes and residues which may influence the sustainability of future land-use activities. The persistent recitations of those in support of continued development and access to the biotechnology of genetic engineering commonly show that any implications there may be of GE-technology for soil and land-use remain largely unrecognised and therefore unevaluated.

Most land-use systems are acknowledged as exerting considerable environmental influence resulting from the production methodologies that are employed. In New Zealand, for example, the effect of forest and bush clearance on erosion of sensitive landscapes has been visually obvious for almost a century. Further environmental influences firmly linked to global land-use methodologies now include nitrate contamination of groundwater, nutrient enrichment of natural waterways, endocrine disruption in animals from agrichemicals and their residues, the role of antibiotics in livestock-feed and the rise of antibiotic-resistant bacterial pathogens in disease therapy, to name a few. The Sierra Club’s recently reported position vis-à-vis GE developments is pertinent:

“Genetic technology, like all other production technologies, will produce its own type of industrial pollution” (“Washington Post”, November 21, 2000).

Genetic contamination (or more properly, pollution) of farm products entering the forage and food-streams of livestock and humans is now becoming well documented. The most recent example receiving wide publicity is the detection of an unapproved trans-genetic insecticidal protein ( from Starlink seed) in corn for the human food stream. While the press emphasis was placed primarily on the contaminant protein in foodstuff, a most serious acknowledgement is that the mechanism of transfer is, surprisingly, unknown. Below ground, information about the effects of GE-plants and animals is growing but still rare and extremely fragmented. There is sufficient evidence to suggest that even in fragmentary form, that biological mechanisms in soil will likely play a crucial role in the overview how GE and other production technologies should be developed, if at all.

This submission focuses primarily on soil DNA and horizontal gene transfer (section B(b)), and soil sorption and ecological effects of transgene products like insecticidal proteins of plant origin (section B(j) ).

References:

Khachatourians, G. C. 1998. Agricultural use of antibiotics and the evolution and transfer of antibiotic-resistant bacteria. Canadian Medical Association Journal, 159:1129-36.

Estrogenicity and Endocrine Disruption. Issue Paper No 16, Council for Agricultural Science and Technology (CAST), Ames, Iowa. July 2000.

Section B (b)

B (b) the evidence (including the scientific evidence), and the level of uncertainty, about the present and possible future use, in New Zealand, of genetic modification, genetically modified organisms, and products

Section B (b) Summary

Assessment of the possible genetic pollution of the soil environment is being ignored in the rush to develop and field test in containment GE plants and animals. Horizontal gene transfer among soil organisms is probably common and the acquisition and transfer of novel DNA-constructs will in all likelihood become part of the gene-flow in the soil biosphere.

B (b) Horizontal gene transfers in the soil biosphere can be ecologically insignificant events.

1. Soil, as an essential component of natural soil-plant-animal systems, receives and processes a constant flow of animal and plant debris and bi-products from land-use systems. This includes the genomic DNA present in each cell.

2. Upon release from animal and plant residues, some of the DNA is then decomposed into its constituent components, but a proportion is able to be readily sorbed onto the clay and organic matter surfaces of soil material. In this state, it can be protected from further enzymatic soil decomposition for extended periods of time lasting up to several months.

3. Extracellular DNA in soil also consists of DNA originating from a huge diversity of indigenous soil organisms as well as plants and animals in the farmed ecosystem. Using a combination of soil extraction and polymerase-chain-reaction (PCR) methodologies,

DNA segments with sufficient size to carry genetic information can therefore remain intact in the soil for several months.

4. The microbial uptake of soil DNA (a condition known as DNAtransformation) is enhanced by its sorption to soil particles, and even though laboratory DNA-transformations are conducted in nutrientrich cultures, nutrient-poor conditions, such as those prevailing in normal soil, have been able to actually enhance gene transfer over laboratory conditions. Even sand-sorbed DNA has been shown to increase the frequency of gene transfer to specific soil bacteria 50-fold over standard culture conditions.

5. Horizontal gene transfer (HGT) between bacteria is well documented. A relevant case in point is the reported transfer of the chromosomal symbiotic gene from inoculant rhizobia (involved in

symbiotic nitrogen fixation) to non-symbiotic rhizobia in soil. HGT may well be enhanced in microcosms of intense soil biological activity such as in the rhizosphere of plants roots, and the gut contents of small soil animals such as springtails (collembola) and earthworms.

6. Lastly, though transfer frequencies in the soil biosphere may appear to be low, each low frequency event could become one with striking ecological/ environmental implications depending on the nature of the selective forces involved.

References

1.Lorenz M.G. and W. Wackernagel. 1994. Bacterial gene transfer by natural genetic transformation in the environment. Microbiological Reviews,58: 563-602.

2.Lorenz M.G., B.W. Aardema and W. Wackernagel. 1988. Highly efficient genetic transformation of Bacillus subtilis attached to sand grains. Journal of General Microbiology, 134: 107-112. 2.

3. Sullivan J.T., H.N. Patrick, W.L.Lowther, D.B.Scott, and C.W.Ronson. 1995. Nodulating strains of Rhizobium loti arise through chromosomal symbiotic gene transfer in the environment. Proceedings of the National Academy of Sciences USA , 92: 8985-8989.3.

4. Nielsen, K.M, A.M. Bones, K. Smalla and J.D. van Elsas . 1998. Horizontal gene transfer from transgenic plants to terrestrial bacteria – a rare event? FEMS Microbiology Reviews 22: 79-103.

Section B (j)

B (j) the main areas of public interest in genetic modification, genetically modified organisms, and products, including those related to:

(i) human health (including biomedical, food safety, and consumer choice)

(ii) environmental matters (including biodiversity, biosecurity issues, and the health of ecosystems)

(iii) economic matters (including research and innovation, business development, primary production, and exports)

(iv) cultural and ethical concerns

Section B (j) Summary -animal production systems remains unevaluated.

Transgene products like the cry-insecticidal proteins are expressed constitutively by GE-plants, and pose unexplored and unanticipated implications for natural food webs in soil involving an array of interacting and interconnected indigenous soil organisms. These soil biosphere organisms may happen to be non-target organisms. The implications of any effect on natural nutrient-cycling in normally operating soil-plant-animal by transgenic products like the insecticidal proteins of Bt deserve close evaluation.

B (j)(ii) Transgenic products in the soil environment.

Transgenic crops such as maize, soybean, and cotton have been developed to produce their own insecticide as a means of plant protection. Bt-plants (i.e. those now containing the gene from the soil bacterium Bacillus thuringiensis) have been engineered to express an insecticidal protein active against specific plant pests.

1. Whereas the natural gene product is a non-toxic precursor form of the protein which becomes activated into its toxic form only in the gut of the insect, the transgenic gene product has been deliberately engineered to be produced by the plant in its actively toxic form, and it is produced in every cell of the transgenic plant. The insecticidal targets of such plants are the biting and chewing immature or adult forms of certain moths, butterflies, european corn borer, beetles, flies, and mosquitoes. Over 100 Bt-genes have been patented.

2. The amount of actual insecticidal protein produced by the transgenic crop over the entire growing season in, say, a corn crop estimated to have a fresh crop (above ground only) weight of 20 to 25 tonnes per hectare at harvest, is colossal. The toxic protein is present in the root exudate of the growing plant and enters the soil around each plant rooting system (the rhizosphere) throughout the entire plant development. At harvest, the stubble and above ground debris, together with the entire root system, begin biological decomposition and involving a huge orchestra of soil animals, fungi, and bacteria. Every biological component of the biosphere has now come into extensive contact with the toxic protein.

3. Contrary to claims, Bt-toxin can remain active in the soil long after crop removal. The reason for this relates to the soil’s capacity to rapidly and tightly this type of protein to the soil surfaces of clays and organic matter fractions. Soil binding of the Bt-protein reduces its susceptibility to degradation and to, in turn, retain its insecticidal activity. Not only does this create an ecological pressure that selects Bt-resistant pests, but it exerts pressure on non-target organisms within the extended cropping system that just happen to possess sensitivity to Bt-insecticidal proteins. The consequences of long-term exposure to Bt by non-target soil animals that are integral processors of crop wastes in nutrient turnover and recycling are largely unexplored.

4. A review of the Bt-effects on non-target species clearly shows that the current testing procedures commonly used are not capable of detecting realistic non-target effects. It appears self evident that the tools in the testing “tool-box” are not the ones now needed in evaluation studies involving transgenic products in the environment. Regrettably, there does not seem to be any forthcoming initiative to develop the sort of “tools” now required.

References

1. Saxena, D., S. Flores, and G. Stotzky . 1999. Insecticidal toxin in root exudates from Bt-corn. Nature 402: 480.

2. Stotzky, G. 2000. Persistence and biological activity in soil of insecticidal proteins from Bacillus thuringiensis and of bacterial DNA bound on clays and humic acids. Journal of Environmental Quality 29: 691-705.

3. Hilbeck, A., M.S. Meier and A. Raps. 2000. Review on non-target organisms and Bt-plants.

Report to Greenpeace International , Amsterdam. EcoStrat GmbH, Zurich, pp77.