Genetically modified microbes are widely deployed in North America

Most of the focus of debate about the widespread and rapid deployment of genetically modified (GM) crops in North America emphasizes the major crops corn, cotton, soy bean, canola and potato. The widespread deployment of GM microbes has been going on for at least six years with little or no public awareness and input into the reviews on environmental impact. The widely deployed GM microbes include the following: Sinorhizobium meliloti a bacterium which is added to soil or used as a seed innoculant to enhance nodulation and nitrogen fixation in legumes, it has seen wide application since its release for commercial production in 1997. The other commercial GM microbes are designated to be biopesticides. These include GM Agrobacterium radiobacter k1026 that is used to treat fruit and vegetable plants to prevent crown gall tumors from appearing. The bacterium Pseudomonas flourescens has been modified with a number of different Cry delta-endotoxin genes from different subspecies of Bacillus thruingiensis (Bt) the resulting biopestide is produced by killing modified P. flouresens, the modified P. flourescns provides a persistent biopesticide that degrades much slower in sunlight than Bt used to control insect pests of fruits and vegetables. Information indicating that the commercial microbial preparations are genetically modified is not widely recognized by those selling or using the preparations and the preparations can easily be employed by organic farmers.

The legume symbiont , Sinorhizobium meliloti, is tremendously important in fixing nitrogen from the air into plants and soil. Legumes signals the bacterium by exuding flavonoids from its roots, activating expression of nodulation genes in the bacterium resulting in the production of Nod factors that regulate formation of nitrogen fixing root nodules (1). The sequence of S.meliloti has been fully determined, the bacterial genome is unusual in that it contains three chromosomes (or a chromosome and two very large plasmids), all three of the bacterial replicons contribute to symbiosis (2). The genetically modified commercial strain (RMBPC-2) has added genes that regulate nitrogenase enzyme (for nitrogen fixation) along with genes that increase the organic acid delivered from the plant to the nodule bacterium and finally the antibiotic resistance to streptomycin and spectomycin are added to the commercial bacterium(3). The commercial release was permitted in spite of concerns about the impact of the GM microbe on the environment. Evidence supporting the initial concerns has accumulated but has not deterred the spread of the GM microbe. For example , a recent review showed that GM S. meliloti strains persisted in the soil for six years , even in the absence of legume hosts. Horizontal gene transfer to other soil bacteria and microevolution of plasmids was observed (4). Other studies showed that a soil micro arthropod ingested S. meliloti and rescience in the arthropod gut facilitated gene transfer to a range of bacteria (5). There is little doubt that the antibiotic markers of GM S. meliloti, streptomycin and spectomycin will be transfer to soil bacteria from which they can be transferred to a range of animal pathogens. For example, the resistance genes for streptomysin and spectomysin were found to be transferred from their insertion as transgenes in plant chloroplast into the infecting bacterium Actinobacter sp. (6) so the mobility of the transgnes are well established. It is clear that the antibiotics , spectinomycin and streptomycin , are used extensively in human and animal medicine. For example spectinomycin is used to treat human gonnnorhea (7) and bovine pneumonia (8) Streptomycin is used to treat human tubeculosis(9) and Meniere’s disease (10) and it is used as a pesticide on fruits and vegetables (11). In conclusion, the commercial release of GM Sinorhizobium meliloti resulted in the soil establishment of the GM microbe in millions of acres of cropland and spread antibiotic resistance genes for antibiotics used extensively in medicine and agriculture.

Agrobacterium radiobacter k1026 (12) is a biopesticide derived from A. radiobacter k84 a natural bacterium used to control the crown gall disease of fruits and ornamental trees and shrubs. It is used to treat germinating seeds or roots and stems of the plants. Crown gall disease is caused by the bacterium Agrobacterium tumefaciens that causes tumors to form on the plant stems (the bacterium is the one used in genetic engineering). GM Agrobacterium radiobacter is used a great deal to control crown gall disease in fruits and ornamental trees. The GM A. radiobacter releases a chemical warfare agent against disease causing A. tumefaciens, the chemical is called bacteriocin ( agrocin )a novel nucleic acid derivative that prevents the crowwn ball tumors from forming in crop plants.The GM A. radiobacter has an engineered deletion in the genes controlling plasmid transfer so that the male bacterium cannot transfer its plasmid but can act as a female to receive a plasmid transfer.The strain is used a great deal to treat fruits and ornamental shrubs and trees, the bacterium appears to be very stable and persist for years in the soil around treated plants.

The other GM biopestides commercially released include a number of Pseudomonas flourescens strains that have been modified with Cry delta endotoxin genes from Bacillus thuringiensis then the transformed P. flourescens strains are killed before being marketed (13). The killed GM bacteria are more persistent used as foliar sprays than are the B. thuringiensis sprays. The main fallacy in the approval of these biopesticides is the fact that bacteria enjoy sex after death. Soil bacteria are easily transformed with cell lysates (squashed dead cells)and function in soil microcosms (14). P. flourescens and A. tumefacians both are transformed in soi(15)l. The soil Pseudomonas and Actinobacter also easlly take up genes from transgenic plants (16) so that combination of transgenic crops and GM biopesticides can create genetic combinations cabable of devastating the soil microflora and microfauna.

In conclusion, GM microbes have begun to be a ubiquitous contributor to the biosphere of North America. This massive commercial invasion took place with little or no public input or knowledge and with very little monitoring to measure the impact of the invasion. The environmental evaluations of the commercial microbes were rudimentary and frequently erroneous , the regulating bureaucrats will certainly maintain that the evaluations were science based and complete , but that is certainly a view that is far from reality.

References are available on request , please state the name of the paper