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In nature, herbicide resistance could confer advantages to plants.

ラウンドアップ 安全性 Credit: Xiao Yang
The use of genetic modification of crops to make them resistant to herbicides has been extensively employed to create advantages for weedy rice varieties. These findings suggest that such modifications may have a wide variety of impacts that extend beyond farms, and even in the wild.

A variety of crops have been genetically modified to be intolerant to the herbicide glyphosate. It was initially marketed under the brand name Roundup. This resistance to glyphosate allows farmers to eradicate the majority of plants without harming their crop.

Glyphosate is a deterrent to the growth of plants. It blocks an enzyme known EPSP synthase. This enzyme plays a role in the creation of specific amino acids as well as other molecules. These substances can account for up to 35% of a plant’s mass. Genetic modification, which is used by Monsanto’s Roundup Ready crops, which are based in St Louis (Missouri), typically involves inserting genes into a crop’s DNA to increase EPSP synthase production. ラウンドアップ 原理 Genes are typically obtained from bacteria that infects the crops.

The plant is able to resist the effects glyphosate thanks to the extra EPSP synthase. ラウンドアップ Biotechnology labs have also attempted to make use of plants’ genes instead of bacteria to boost the production of EPSP synthase and, in turn, to take advantage of the loophole in US law that allows regulatory approval of organisms carrying transgenes not made from bacterial pests.

Few studies have investigated the possibility that transgenes, such as glyphosate-resistant ones could — after introduction to weedy or wild plants by cross-pollination — enhance the competition of plants in reproduction, survival and growth. Norman Ellstrand of University of California Riverside declares, “The conventional expectation is that any transgene that is found in nature will confer disadvantage if there’s no selection pressure because the extra machinery could reduce the health.”

ラウンドアップ 影響 Lu Baorong is an ecologist at Fudan University Shanghai. His study shows that resistance to glyphosate offers a significant health benefit even when it’s not applied.

Lu and his coworkers modified the cultivars of rice to make more EPSP synthase. They also crossed the modified rice with a weedy-related. Their work was published in NewPhytologist 1.

The team allowed the offspring of cross-breeding to cross-breed to create second generation hybrids. They were identical genetically with the exception of the amount of EPSP synthase genes they had. The ones with more copies expressed greater amounts of the enzyme, and produced more of the amino acid tryptophan than their non-modified counterparts.

Researchers also found that transgenic hybrids were photogenic, had more seeds per plant and had 48-125% higher yields of seeds than the non-transgenic varieties.

Lu believes that making weedy invasive rice more competitive may make it harder for farmers to repair the damage caused by this insect.

“If the EPSP-synthase gene is introduced in the wild rice plant, their genetic diversity, which is really vital to preserve, could be threatened because the transgene’s genetic make-up could outcompete natural species” Brian Ford-Lloyd, a plant geneticist at the University of Birmingham, UK. This is among the most evident examples of plausible harmful effects [of GM crop] on the environment.”

The public has a perception that genetically engineered crops with more copies or microorganisms’ genes are more secure than those that only contain their own genes. Lu says that the study “shows that this isn’t always true”.

Researchers have concluded that these findings should prompt a reconsideration of the way that genetically modified crops will be controlled in the near future. Ellstrand says that “some people believe that biosafety regulation could be relaxed since we have a an incredibly comfortable relationship with genetic engineering for two decades.” “But the research shows that novel products still need an unbiased evaluation.” ラウンドアップ