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In the wild, plants can be treated with herbicides.

Credit Xiao Yang
It has been proven that a genetic modification technique that is used extensively to create crops that are herbicide-resistant confers advantages on an invasive variety of rice. The results suggest that the benefits of such modification have the potential to extend beyond the confines of farms into the wild.

ラウンドアップ Several types of crops are genetically modified to resist glyphosate, a herbicide that was first sold under the brand name Roundup. Farmers are able to eliminate herbicides from their fields by using glyphosate without harming their crops because of this resistance.

Glyphosate may hinder the growth of plants by inhibiting EPSP synase which is an enzyme that plays a role in the creation of amino acids as well as other chemicals that make up about 35% of the plant’s mass. The technique of genetic modification, which is used by Monsanto’s Roundup Ready crops, which are based in St Louis (Missouri), typically involves inserting genes in the DNA of the crop to increase EPSP synthase production. The genes typically come from bacteria that are infected with plants.

The plant is able to endure the negative effects of glyphosate since it has an extra EPSP-synthase. Biotechnology labs also have tried to create EPSP synthase with more plant-based components than bacteria using genes that come from plants. This was partially done to exploit a loophole found in US law that allows the approval of regulatory authorities for organisms which aren’t the result of bacterial parasites.

Few studies have investigated the possibility that transgenes like glyphosate-resistant genes can — once introduced to wild or weedy plants by cross-pollination — increase the competitiveness of these plants in reproduction, survival and growth. “The conventional belief is that any transgene will confer disadvantage in the wild, in the absence of pressure to select, due to the fact that any additional machinery will reduce the fitness,” says Norman Ellstrand, a plant geneticist at the University of California in Riverside.

But now a study led by Lu Baorong, an ecologist at Fudan University in Shanghai, disproves that belief: it shows that the weedy version of the popular rice crop, Oryza sativa, gets a significant fitness boost from the resistance to glyphosate even when glyphosate isn’t applied.

Lu and colleagues altered cultivars of rice to improve its EPSP synthase. The modified rice was crossed with a wild ancestor.

ラウンドアップ グリホサート The group allowed the offspring of crossbreeding to crossbreed with one another, resulting in second-generation hybrids that are genetically identical to each other except for the amount of copies the gene encodes EPSP synase. ラウンドアップ 稲 The team found that those who had more copies of the gene encoding EPSP synthase expressed more enzymes and produced more tryptophan, in line with what was expected.

ラウンドアップ 風 Researchers also found that transgenics had higher rates, more flowers, and 48-125percent more seeds/plant than nontransgenics.

Lu believes that making rice that is weedy less competitive might make it harder for farmers who have their land infested by the pest.

“If the EPSP-synthase gene is introduced in the wild rice species their genetic diversity, which is really vital to preserve may be at risk as the transgene’s genotype will outcompete the natural species” Brian Ford-Lloyd an expert in plant genetics at the University of Birmingham, UK. ラウンドアップ “This is one of the clearest examples of extremely plausible damaging effects of GM crops] on the environment.”

Many people believe that genetically modified plants containing more copies of their own genes than those from microorganisms are safer. This belief is not supported by the study. Lu says that Lu’s research does not contradict this view.

ラウンドアップ Researchers believe that these findings should prompt a rethinking of the way that genetically modified crops are regulated in the near future. Ellstrand believes that biosafety rules can be relaxed since we can benefit from a high degree of comfort from two decades worth of genetic engineering. “But the study still shows that novel products require careful evaluation.”