When UC Berkeley’s Ignacio Chapela and David Quist discovered evidence that genes from commercially engineered crops had invaded native maize strains in the Mexican heartland where native peoples have first bred the grass-like teosinte into modern corn, Monsanto began a smear campaign that cost Chapela his professorship. [Previously, and here’s a story I wrote at the time.]
It took a lawsuit to win Chapela tenure at Cal, but the corporate muscle displayed by the Big Agra nearly destroyed a promising career and sent a powerful message to other researchers about the dangers of challenging Monsanto’s hunger to control the world’s crops.
Subsequent research has confirmed the migration of engineered genes into a variety of crops — including Mexican maize strains.
And now researchers are gaining an understanding of one way those genes may jump between genetically engineered varieties and across species barriers.
Here’s the announcement of the discovery by British researchers:
Scientists at the University of Bristol have discovered a previously unknown route by which GM genes may escape into the natural environment.
By studying plant-fungi-bacteria interactions at plant wound sites, the team have identified a natural process stimulated by a hormone released by the wounded plant that would allow synthetic genes to move across organisms and out into the wild.
The bacterium Agrobacterium tumefaciens transforms plant tissue as part of its infection process. This natural process provides an important toolbox for scientists to genetically manipulate many species of plants. Recently this technology has been developed for non-plant organisms including fungi by the Bailey & Foster Group in Bristol’s School of Biological Sciences.
Their success has come from adding the plant wound hormone acetosyringone, which triggers Agrobacterium transformation mechanisms and allows foreign genes to modify cells (genetic transformation). In the natural environment Agrobacterium and fungi likely encounter each other at plant wound sites where acetosyringone is present, raising the possibility of natural gene transfer from bacterium to fungus.
Professor Gary Foster and colleagues tested whether transformation of fungi by Agrobacterium can occur in nature on plants. Their results clearly demonstrate that when placed together on damaged plant tissue, Agrobacterium readily transforms associated fungi. “This suggests a previously unknown route for horizontal gene transfer in nature,” said Professor Foster.
These results may have implications for the risk assessment of GM plants generated via Agrobacterium-mediated transformation. Agrobacterium can survive within plant tissue following artificial transformation in tissue culture, and can be detected within regenerated transgenic plants. This research shows that these bacteria have the potential to move the same genetic modifications to fungi in a natural environment.
Prior to release of a GM plant, elimination of Agrobacterium following modern genetic modification is a key concern of geneticists and policy makers as it is essential to prevent later escape of synthesised gene from Agrobacterium to other organisms.
Professor Foster said: “This study suggests that the encounter between Agrobacterium and a fungus on the plant surface may lead to gene flow in a previously overlooked way, potentially leaking GM genes into the natural world.”
Chapela hails findings as ‘a major landmark’
Writing at GM Watch, Chapela commented on the findings:
The careful and understated presentation, beginning with the title, belies research results that I think should be considered a major landmark in the growing evidence demonstrating how little we know about the ecological consequences of transgenesis, in particular the potential for horizontal gene transfer in real field situations. It also shows a definite and probably very important source of concern, the real possibility that DNA vectored into plants could move out, with full reproductive capacity, via a microbial route into the genomic environment far and beyond the immediate space and phylogeny of the host plant. Any environmental evaluation of field releases should now be required to seriously consider this possibility.
The research for this paper is carefully conceived and conducted, using various sources of confirmatory evidence. The frequency of “spontaneous” transformations out of the bacterium and into the fungus (2 out of 17, 1 out of 15, 10 out of 31 and 14 out of 42 trials in various repetitions) is exceedingly high. Although the paper demonstrates the transfer “only” from whole bacterial cells onto fungal spores (or hyphae), a precautionary approach should dictate that the possibility be also considered that transfers could occur through back- transformation, since much of the Agrobacterium wherewithal necessary to accomplish it is present in the transgenic plant. It is also known that whole Agrobacterium can “hide” through the process of regeneration of plants out of callus in the transgenesis process, providing accessible cells for the transformation, and of course encounters of Agrobacterium and different fungi (and other organisms?) at a plant-wound site must be considered common in the field.
Finally, the authors minimize the possible importance of their findings (perhaps appropriately so, especially to avoid a firestorm over their heads) by suggesting that there should be no biological consequences to the transformation unless the transferred DNA provides some measurable advantage to the carrier fungus. I disagree: We know that there are (a) many examples of apparently “silent” DNA that nevertheless has very important consequences, and (b) many functions of transgenic DNA that may not be predicted by the designs of the people doing the original transformations. DNA does not necessarily need to give an advantage to the carrier; all it needs to do is survive and reproduce. It is unwarranted arrogance to suggest that we know what its functions may be or indeed may become downwind, downtime and down across the phylogenetic landscape.
The full paper, “Investigating Agrobacterium-Mediated Transformation of Verticillium albo-atrum on Plant Surfaces,” is available online here.
More bad news for Monsanto
Much of Monsanto’s efforts have focused on development of crops that are highly resistant to pesticides, especially its own house brand, Roundup.
Some researchers cautioned that widescale use of the herbicide would inevitably lead to the rise of “superweeds,” plants that could thrive where others died and present a whole new level of threat to the company’s genetically engineered crops.
Well, guess what?
From Charles Margulis at Generation Green:
There’s been much recent news about Monsanto paying farmers to use its competitors’ herbicides, in what many see as a last ditch effort to address the spread of superweeds created by the company’s “Roundup Ready” (RR) GMO crops.
Environmental scientists warned even before Monsanto’s “herbicide tolerant” GMO crops were approved that they would hasten the evolution of resistant weeds. For these scientists, the issue was obvious: introduction of high doses of a single chemical year after year would result in the exact conditions needed to breed resistance: weeds with resistance genes would be the only weeds that could survive and breed, leading to superweeds that are unaffected even by massive herbicide spraying.
Of course, Monsanto denied these early warnings. In a 1997 paper, Monsanto scientists claimed that weed resistance was such a complex genetic phenomena that RR crops would be unlikely to lead to resistant weeds. What’s even more troubling, though, is that Monsanto continued to ignore the spread of superweeds for years, and worked to persuade and threaten farmers against strategies to avoid resistance – since those strategies would have cut into the company’s sales of Roundup and RR crops.
For example, in a 2003 report, a Monsanto “Roundup technical manager” advised against crop rotation and warned farmers that using chemicals other than Roundup with RR crops would only add an unnecessary expense. Farmers have been growing Roundup Ready soy continuously for eight years, he said, without any resistance problems. Weeds were not resistant, he said, but were exhibiting “differential tolerance.”
Which means, he said, farmers should simply use more Roundup to kill resistant weeds, because “if it’s a dead weed, it won’t produce seed.”
Which is funny, because two years earlier, scientists in Delaware reported that ten times the recommended amount of Roundup was ineffective on a resistant weed strain (perhaps they should have tried 100 times the label amount).
In fact, Monsanto was spreading their “use more Roundup, because dead weeds don’t seed” line far and wide. In a 2003 pamphlet on “managing weed resistance” it sent to thousands of farmers, the company advised the growers to use maximum doses of Roundup and warned that switching to rotations with non-GMO crops would cost farmers money.
The Monsanto propaganda was so offensive to weed scientists that one inducted the company’s flyer into his “Herbicide Ad Hall of Shame,” stating that “Almost all weed scientists agree that the evolution of resistant biotypes is inevitable with the current use pattern of glyphosate. Increased adoption of rotations relying solely on RR crops will greatly enhance the rate that resistance evolves.”
eats shoots 'n leaves 