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In the wild, herbicide resistance could confer advantages to plants.

Credit Xiao Yang
A technique of genetic modification widely used to make crops herbicide resistant has been found to give advantages to a weedy form of rice even in absence of the herbicide. The finding suggests that the benefits of such modification could extend beyond the confines of farms into the wild.

Several types of crops have been genetically modified to be resistant to glyphosate, an herbicide first sold under the brand name Roundup. Farmers can eliminate the majority of herbicides from their fields using this glyphosate-resistant crop without damaging their crops.

Glyphosate blocks the enzyme EPSP synthase that is responsible for the creation of specific amino acids and other molecules. It can also inhibit the growth of plants. The genetic-modification technique — used, for instance in the Roundup Ready crops made by the biotechnology giant Monsanto located in St Louis, Missouri — typically includes inserting genes into a crop’s genome to increase EPSP-synthase’s production. Genes typically come from bacteria that cause disease to plants.

This extra EPSP synthase allows plants to resist the effects of glyphosate. Biotechnology labs are also attempting to utilize genes from plants rather than bacteria to increase EPSP synthase. This is partly because the US law permits regulatory approval that allows organisms that carry transgenes to get approved.

Few studies have explored the possibility that transgenes that confer tolerance could — after they become weedy or wild relatives via cross-pollinating -can boost the plant’s survival and reproduce. ラウンドアップ Norman Ellstrand of University of California Riverside declares, “The conventional expectation is that any type of transgene found in the wild could cause disadvantages if there is no selection pressure because the extra machinery could lower the fitness.”

ラウンドアップ Lu Baorong is an Ecologist in Fudan University Shanghai. His study shows that glyphosate resistance is a major fitness benefit, even though it’s not used.

Lu and coworkers modified the cultivars of rice to improve its EPSP synthase. The modified rice was crossed with a wild relative.

ラウンドアップ,2084008038,2084034075&rewrite_ok_wand_re_search=1 The team then allowed breeding offspring that were cross-bred together to produce second-generation hybrids. These were genetically identical with the exception of the number and copy count of EPSP synthase gene. Like one might expect, the more copies produced higher levels of enzyme, and also more tryptophan, than their counterparts that were not modified.

Researchers also discovered that the hybrids with transgenic genes had higher rates of photosynthesis. They also produced more flowers and shoots and produced 48-125% more seeds than the non-transgenic hybrids -without the use of the chemical glyphosate.

Making weedy rice more competitive can increase the issues it creates for farmers across the globe whose plots are invaded by pests, Lu says.

Brian Ford-Lloyd, a UK plant geneticist and says, “If the EPSP synthase gene gets in the wild rice species their genetic diversity could be endangered, which is important because the genotype with transgene outcompetes the normal species.” “This is an illustration of the most probable and damaging effects of GM crops on the environment.”

The general public believes that genetically modified plants containing more copies of their own genes than those from microorganisms are safe. This is however questioned by this study. Lu declares that “our study is not proving this to be the case.”

Certain researchers believe that this finding requires a review of the future regulation of crops that have been genetically modified. Ellstrand states “Some people believe that biosafety regulation should be relaxed.” Ellstrand adds: The study found that any new products must be evaluated carefully.