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The wild plants could have an herbicide resistance advantage.

ラウンドアップ Credit Xiao Yang
A common technique for genetic modification of crops to make them resistant to herbicides has been found to give advantages to weedy varieties of rice, even when herbicide is not present. This finding suggests that the modifications could affect the environment beyond farms.

ラウンドアップ 撒き方 Many crops are created genetically to be resistant to glyphosate. ラウンドアップ This herbicide, first called Roundup it was released on the market in the year 1996 under the tradename Roundup. This allows farmers to remove the majority of weeds from their fields without harming their crops.

Glyphosate can inhibit plant growth by inhibiting EPSP synase which is an enzyme involved in the production amino acids and other chemicals that make up about 35% of plants’ mass. The genetic-modification technique — utilized, for instance, in the Roundup Ready crops made by the biotech giant Monsanto, based in St Louis, Missouri -usually includes inserting genes into a crop’s genome to boost EPSP-synthase production. The genes are often derived from bacteria that has affected the plants.

The added EPSP synthase helps the plant resist the effects of glyphosate. Biotechnology labs have also attempted to use plants’ genes to increase EPSP-synthase, partly to take advantage of a loophole in the American system that permits regulatory approval of transgenes that are not derived from bacteria-based pests. A few studies have explored the possibility that transgenes, like those that confer resistance to glyphosate, could increase the resilience of plants to surviving and reproduce once they cross-pollinate with weedy or wild species. ラウンドアップ Norman Ellstrand of University of California Riverside states, “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 fitness.”

Lu Baorong (an ecologist at Fudan University, Shanghai) has now questioned that opinion. ラウンドアップ It has shown that glyphosate resistance can give a significant fitness boost to the weedy rice crop called Oryza sativa even when it is not in use.

In the study which was published this month in New Phytologist 1, Lu and his coworkers genetically altered the rice cultivar to enhance its own EPSP synthase. They also crossed-bred the modified rice with a weedy ancestor.

The researchers allowed offspring of cross-breeding to mix with one another, resulting in second-generation hybrids genetically identical to each other except for the amount of copies of the gene encoding EPSP synase. The team found that those with greater copies of the gene that codes for EPSP synthase expressed more enzymes and also produced more tryptophan as expected.

Researchers also discovered that transgenic hybrids produced between 48-125% more seeds per plant, had greater rates of photosynthesis and more shoots than those that were not transgenic.

Lu suggests that making the weedy rice more competitive may increase the risk for the farmers around the world who’s fields are infested with the pest.

Brian Ford-Lloyd is Brian Ford-Lloyd is a UK plant geneticist who says, “If the EPSP synthase gene gets in the wild rice varieties their genetic diversity will be at risk, which is significant because the genotype with transgene has a higher level of competition than the standard species.” “This is one the most evident instances of extremely plausible negative effects [of GM crops] on the natural environment.”

The public has a perception that genetically engineered crops with more copies or microorganisms’ genes are less risky than those that only contain their own genes. “Our study suggests that this isn’t always the case,” says Lu.

The findings call for a reconsideration of the future regulation of genetically modified crops, some researchers suggest. Ellstrand claims that some people believe biosafety regulations can be relaxed given the past over two years of genetic engineering. “But the research shows that the new technologies require an unbiased examination.”