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In the wild, resistance to herbicides may confer advantages on plants.

Credit Xiao Yang
A method of genetic modification used extensively to make crops herbicide resistant has been shown to confer advantages on the weedy rice, even in absence of the herbicide. This suggests that the modifications could affect the environment beyond farm.

A wide range of crop varieties have been genetically modified so that they are immune to Roundup herbicide glyphosate. This glyphosate-resistant crop allows farmers to eliminate the majority of weeds from the fields without causing damage to their crop.

Glyphosate slows the growth of plants by inhibiting EPSP synthase (an enzyme that is involved in the creation of certain amino acids and various other molecules). This enzyme could make up as much as 35 percent or more of a plant’s total mass. Genetic modification, which is used by Monsanto’s Roundup Ready crops, which are based in St Louis (Missouri), typically involves inserting genes into the DNA of the crop to increase EPSP synthase’s production. The genes are usually derived from bacteria that infect plants.

The plant is able to resist the effects of glyphosate because of the additional EPSP synthase. Biotechnology labs have also tried to use plants’ genes instead of bacteria to boost EPSP-synthase production and, in turn, to take advantage of an inconsistency within US law that facilitates approval by regulators of organisms that have transgenes that aren’t derived from bacterial pests.

There aren’t many studies that have examined whether transgenes that confer glyphosate tolerance may — once they become weedy or wild relatives via cross-pollinating — increase the plants’ longevity and reproductive. ラウンドアップ of University of California Riverside says, “The conventional expectation is that any transgene that is found in nature will cause disadvantages if there is no selection pressure because the extra machinery could lower the health.”

Lu Baorong, an ecologist from Fudan University in Shanghai has changed the way that he views this. He discovered that glyphosate resistance provides an impressive fitness boost to a weedy variant of the standard rice plant Oryza Sativa.

Their research was published in 1. Lu and his collaborators altered the genetics of cultivated rice to boost its EPSP synthase expression , and then crossed it with a weedy counterpart.

The group then allowed the offspring of cross-breeding to cross-breed to create second generation hybrids. ラウンドアップ were genetically identical apart from the number of EPSP synthase genes they carried. As expected, with more copies of the gene had greater levels of enzymes and produced an increased amount of amino acid tryptophan compared to their counterparts that were not modified.

Researchers also found that transgenic hybrids produced 48-125% more seeds per plant, and had higher photosynthesis rates and produced more shoots than non-transgenic ones.

Lu believes making weedy, aggressive rice more competitive could make it harder for farmers to repair the damage caused by this bug.

Brian Ford Lloyd, a UK plant scientist, said that the EPSP Synthase gene could get in wild rice varieties. This would threaten the genetic diversity of their species, which is very vital. This is among the most evident examples of likely negative effects of GM crop] on the environment.”

The public has a perception that genetically engineered crops with extra copies or microorganisms genes are safer than ones that only contain the genes of their owners. claims that the research does not contradict this notion.

Researchers believe this finding calls for rethinking the future regulation on genetically modified crops. ラウンドアップ says “Some people think that the biosafety regulations should be eased.” Ellstrand addsthat “But the study proved that novel products still require careful evaluation.”