By Asher M. Wright
All across the United States stands of Alfalfa in different stages of growth are reaching to the sky; putting on their spring growth and preparing for a productive season. Some stands are dealing with weevils, others with low pH or insufficient micronturients, but for the first time in history, much of this acreage is not dealing with weed pressure. As many of you know, the U.S. has recently approved Roundup® Ready Alfalfa. This article will attempt to clarify the issue by discussing the transgenic technology of RR alfalfa as well as other political and socioeconomic issues surrounding the crop.
Alfalfa (Medicago sativa) is a broadleaf perennial legume in the Pea family (Fabaceae) and is the most widely cultivated forage legume in the world; in 2006 the FAO estimated 456-million tons were used globally. Alfalfa is primarily cut for hay production, but can be grazed or used as a cover crop as well. The United States is the largest producer worldwide and the only country where Roundup® Ready (RR) Alfalfa has been approved for cultivation (For the purpose of this paper, all values will refer to U.S. production only). Alfalfa is the nation’s third most valuable crop occupying more than 22-million acres (8.9 million ha); it is the premier feed for the dairy industry and is commonly used in beef, sheep, and horse operations as well (Van Deynze, A., et al., 2004). Alfalfa is a very valuable forage crop for a number of agronomic reasons, and like many other types of forages, is at its highest risk for failure during seedling establishment. Compared to the other RR crops however; alfalfa is actually not that difficult to establish and grow. It is a hardy, deep-rooted perennial that actually competes well with weeds (Hall, M. H., et al., 2004). So why do farmers even need RR alfalfa? Well the truth is, it depends on who is asked. This paper will attempt to clarify the issue by discussing the transgenic technology of RR alfalfa as well as other political and socioeconomic issues surrounding the crop.
Alfalfa is not the first U.S. crop that has been modified to exhibit resistance to glyphosate, the active ingredient of Roundup® that actually kills the plant. In fact, soybean, maize, sorghum, canola, sugar beat, and cotton are all RR crops. Glyphosate is a broad-spectrum herbicide first patented by Monsanto Company in 1970 and marketed as Roundup. The patent expired in 2000, and today glyphosate is the most widely spread herbicide in the U.S. with an estimated 94,000 tons (not including alfalfa) used annually, according to the 2007 Pesticide Industry Sales and Usage Report. Compared to its predecessor’s 2,4-D and Atrazine, glyphosate has been hailed as a savior for lower mobility rates in the soil, and a shorter persistence time in aquatic environments (Shipitalo M.J., et al., 2008). Though a number of third party studies have shown glyphosate to have adverse effects on animals, there has been little published research on the effects of glyphosate on humans, and almost no regulation within the U.S.
So how exactly does this compound work?
Glyphosate (N-[phosphonomethyl]glycine) is “undoubtedly the most effective non-selective foliar herbicide available” according to Steve Orloff’s progress report on RR alfalfa (Orloff, S., et al., 2003). It works on dozens of annual and perennial broad-leaf weeds by irreversibly binding to the active site of the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). EPSPS is the initial catalyst to two reactions that ultimately result in the synthesis of chorismate, an essential precursor in plants for the aromatic amino acids: phenylalanine, tyrosine, tryptophan. Without these essential amino acids, the plant cannot function and will soon die. The biochemical pathway of glyphosate is approximately the same in all plants and therefore the method for genetically engineering the “immunity” is approximately the same as well.
The first papers on Recombinant DNA technology began to appear in 1972 and the technology was patented in 1980, with human insulin as the first product released on the market. Monsanto Company quickly took notice and began some research and development of their own. They discovered that a certain soil bacteria known as Agrobacterium sp. strain CP4 produced a glyphosate-tolerant form of the enzyme EPSPS which was designated CP4-EPSPS (Monsanto, 2005). When the CP4-EPSPS gene is incorporated into a plant’s DNA, the resistant enzymes created will ultimately lead to a resistant plant. The resistance stems from the fact that there are extra copies of the novel CP4-EPSPS gene thus extra copies of the novel enzyme; CP4-EPSPS does not replace the EPSPS gene. This is the basic premise for all RR crops and the mechanism used by Monsanto to create immunity; but how does the gene get into the DNA?
Biolistic particle delivery systems also known as gene guns or biolistics are devices that have the ability to inject cells with genetic information. The bullet or payload is a heavy metal coated with Plasmid DNA. Plasmids, often found in bacteria, are double stranded DNA rings that have the ability to replicate independently of standard cellular DNA replication mechanisms. When used in genetic engineering a plasmid is known as a “vector”. Through breeding technology, microbiologists and geneticists are essentially able to insert the desired plasmid into a new bacteria cell, after the cell replicates they can ID the “incorporated” cells with antibodies, and thus isolate the desired plasmid. Once the plasmid has been isolated and replicated, it can be injected into any plant cell with biolistic technology. Monsanto Company used the Agrobacterium sp. plasmid PV-MSHT4 (Figure 2.0) as a vector and incorporated the CP4-EPSPS gene into the DNA of alfalfa. In reality, this was only the beginning, and was actually the easy part.
Alfalfa is a perennial, autotetrapolid with four sets of eight chromosomes (n=8 and 4×8=32 chromosomes). This means alfalfa contains four copies of all gene loci, a key feature to the success of the program. Alfalfa also exhibits genetic self-incompatibility or self-sterility, and is affected very negatively by inbreeding. Because of this trait and the inability to achieve “high trait purity” through self-crossing, a strategy was needed to minimize inbreeding depression. Forage Genetics International (FGI) in partnership with Monsanto Company developed a complex breeding system to prevent “inbreeding depression” and after 5+ years of subsequent field trials they had produced a viable seed. (Figure 1.0) The research found plants to have anywhere from 1-8 copies of the CP4-EPSPS gene, and that the RR phenotype was exhibited in the plant, no matter how many copies of the gene it had. Roundup Ready alfalfa was finally ready for the market (Monsanto, 2005).
The U.S. Animal and Plant Health Inspection Service (APHIS) requires field trials and Ecological Impact Studies (EIS) for all new biotechnology crops, and in 2001 and 2002 an EIS study, funded by Monsanto have you, was conducted on 940 roadside sites of 47 counties in California, Idaho, Pennsylvania, South Dakota, and Wisconsin. Approximately 22% of the sites contained populations of “feral” alfalfa, the at risk species for gene transfer. Monsanto’s 2001 and 2002 EIS concluded: “Proximity of feral populations to cultivated alfalfa suggests that gene flow will occur between these populations. Gene flow in seed production regions, however, may be limited by the management practices used by seed producers to control feral populations and to ensure varietal genetic purity. In forage production systems, pollen flow from cultivated alfalfa is minimized by continual harvest of the forage at early bloom throughout the growing season. The consequences of gene flow from cultivated Roundup Ready alfalfa to feral alfalfa, in terms of increased pest potential, are low because (1) phenotypic evaluations concluded that the introduction of the Roundup Ready trait does not increase the fitness of alfalfa, (2) feral populations are not typically controlled using herbicides, and (3) where controlled, glyphosate is not the only herbicide used as other more, effective herbicides are available “ (Kendrick, 2001). After the EIS and other field trials in California, researches stated, “These results clearly demonstrate [that] there is a fit for Roundup Ready alfalfa in California.” Their conclusion did not come without a disclaimer however: RR alfalfa is not a “panacea” and weed resistance will still present problems in alfalfa production systems.
As initial research and development of RR alfalfa came to a close in 2004, APHIS granted ‘non-regulated’ planting status to the crop, which was quickly followed by a lawsuit from concerned citizens putting a moratorium on the non-regulated status in 2005. At this point the case bounced around the California courts and in 2007 a government required, APHIS-managed EIS was implemented. In 2010, APHIS released the final version of the EIS, and held a number of public forums to allow for comments and concerns. In 2011 after the proceedings, they stated that RR alfalfa would be granted non-regulated status. They made their decision after conducting a “thorough and transparent examination of alfalfa through a multi-alternative EIS and several public comment opportunities, and determining that RR alfalfa does not pose a plant pest risk” (APHIS History, 2012). To many this was a blessing, and to others a curse, but what exactly are the pros and cons?
From a production standpoint there are obvious benefits to a Roundup system. Weeds prevent successful seedling establishment, diminish overall yield, and bring a lower value to hay when present in the bales. Why wouldn’t a manager want to spray a field of alfalfa a couple of times a year to ensure a higher quality, higher yielding, “less headache” of a crop? Well the answer is fairly simple, but the reality is there is little transparent, peer-reviewed, third party (meaning not funded by Monsanto) research on the subject. There are few U.S. scientists willing to lay their heads on Monsanto’s chopping block. One scientist doing research on the “other-side-of-the-fence” is Purdue University’s plant scientist and pathologist Dr. Don Huber. As a leading expert in the field, he believed that there needs to be further research on RR alfalfa before release, and lead a petition of concerned U.S. citizens with a well-crafted letter to Secretary of Agriculture Tom Vilsack, urging him to halt the non-regulated status of this crop. He was denied, and the first non-regulated seeds were planted in 2011.
The main downsides of glyphosate, according to an interview with Dr. Don Huber in December of 2011, is that glyphosate, like many other herbicides and pesticides is a metal chelator (Mercola, D., 2011). Chelation is the formation of a coordinated compound, which is essentially a larger multiple bonded molecule (glyphosate), wrapped around a central metal (micronutrient). Plants have been shown to have difficulty taking up chelated form of the micronutrient (Huber, D. W. 2007). This poses a threat because the transition metal cations that serve as micronutrients (Fe, Mn, Cu, Zn) will show up in the soil test but are unavailable to plants (Huber, D. W. 2007). Though this initial problem with glyphosate is a large one, it is not the entire story.
When plants are suffering from a micronutrient deficiency, and in some cases plants showed 80-90% reduction in Mn and Zn, they are more susceptible to pests and disease. According to Johl and Huber’s research in the European Journal of Agronomy, “Extended use of glyphosate can signiﬁcantly increase the severity of various diseases by impacting all four of the interacting components of the “plant disease diamond” comprised of the plant, abiotic and biotic environments, and pathogens. Reduced growth, impaired defenses, impaired uptake and translocation of nutrients, and altered physiology of plants by glyphosate can affect susceptibility or tolerance to various diseases (Johal, G. S., Huber, D. W. 2009). Glyphosate not only affects plants, but also soil biota. It is detrimental to the health of bacteria and has been shown to be playing a major roll in the microbial population shifts seen today. For example, toxic botulism was rarely seen in dairy cows, and today through selection pressure from glyphosate, is a favored bacterium that is having negative effects on the dairy industry (Mercola, D., 2011). Overall there are apparent positives and negatives to the use of glyphosate, but is it really sustainable?
Based on the research reviewed, it is clear that the data can go both ways. The issue of RR alfalfa, like other GE crops, quickly becomes a philosophical debate based on one’s ideals of conservation, biodiversity, and human health. There are obvious are pros and cons to RR alfalfa and glyphosate. But the truth is, from an Ecological and Social Equity standpoint (66% of the sustainability triangle) the cons far outweigh the pros. There are a number of studies that have linked glyphosate to the development of “Super Weeds”, resistant to the herbicide (Orloff, S., et al., 2003). There are also a number of studies that link Roundup (the mixture of glyphosate and other chemical stabilizers to aid in cellular delivery of the herbicide) to cancers, and irregular livery and kidney function. In research glyphosate actually shows little damage to animals; it is the “stabilizing” compounds that are in Roundup® that are truly the issue (Seralini, G.E., et al., 2011). One final issue is the risk of transgenic gene flow, and it’s impact on Organic producers or other farmers that choose not to plant RR alfalfa. The Supreme Court has recently ruled in favor of Monsanto; any farmer possessing a plant with the patented genes will be held accountable. With an environmental impact study that showed gene flow from RR alfalfa to other varieties as being possible, this is an atrocity and a violation of civil liberties. The only real sense that RR alfalfa makes is economic, and it is a fairly one-sided economic benefit. So what happens now?
Assume that half of the 22 million acres (8.9 ha) of alfalfa in the U.S. are planted to Monsanto’s patented RR variety, and that 1, 50-lb bag of seed, under proper planting, will
cover 2.5 acres. At a price of 4$/lb. of seed, one bag equals $200.00 U.S. dollars (this price will fluctuate depending on state). So 11-million acres divided by 2.5/acres/bag is 4.4 million acres at $200.00/bag is an 880 million dollar a year industry, with the majority of the profits funneling into the pocket of Monsanto Company. So the next time someone asks why the U.S. is planting so many acres of GE crops, it will be obvious why. Until the economics fail or the employees of Monsanto Company and otherlarge agribusiness firms become less integrated with the U.S. regulatory system(Figure 3.0), RR alfalfa and other crops will continue to be planted at the expense of ecological integrity and social equity. No herbicide or pesticide can ever replace good management; so it’s time to put down the crutch, and start using the brain.
APHIS History. (2012) http://www.aphis.usda.gov/biotechnology/alfalfa_history.shtml
Johal, G. S., & Huber, D. W. (2009). Glyphosate effects on diseases of plants. European Journal of Agronomy, 144-152.
Kendrick, D., et al., (2005). Biogeographic survey of feral alfalfa populations in the U.S. during 2001 and 2002 as a component of an ecological risk assessment of roundup ready alfalfa®. Proceedings, The ASA-CSSA-SSSA International Annual Meetings.
FAOSTAT Faostat.fao.org. FAO, 2006.
Hall, M. H., et al., (2004). Alfalfa establishment guide. Plant Management Network International.
Huber, D. W. (2007). What about glyphosate-induced manganese deficiency? Fluid Journal, 20-22.
Mercola, D., (2011). The hidden epidemic killing your gut flora [Television series episode]. In Mercola, D. (Executive Producer), Mercola: Take Control of Your Health. etrieved from http://articles.mercola.com/sites/articles/archive/2011/12/10/dr-don-huber-interview-part-1.aspx.
Monsanto. (2005). Safety assessment of roundup ready alfalfa events J101 and J163. Executive Summary, 1-32.
Orloff, S., et al., (2003). Progress in roundup ready alfalfa. Proceedings, California Alfalfa Symposium, 18-26.
Shipitalo, M.J., et al. (2008). Impact of Glyphosate-Tolerant Soybean and Glufosinate-Tolerant Corn Production on Herbicide Losses in Surface Runoff. Journal of Environment Quality 37 (2): 401–8.