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Wild plants might be able to resist herbicides.

Weedy rice may take on transgenes from genetically modified rice through cross-pollination. Credit: Xiao Yang
A method of genetic modification used extensively to make crops herbicide resistant has been shown to confer advantages on a weedy form of rice even in absence of herbicide. The findings suggest that this modifications could have positive effects on wild rice varieties, as well as the crops.

Many varieties of crops have been genetically altered to be resistive to the glyphosate. Roundup was the first herbicide that was marketed. ラウンドアップ Farmers can eradicate most the weeds that grow in their fields by using this glyphosate resistance , without causing damage to their crops.

Glyphosate acts as an inhibitor of plant growth. It blocks an enzyme known as EPSP synthase. This enzyme is responsible for the production of certain amino acids and other molecules. These compounds could make up as much as 35% of a plant’s mass. The genetic modification technique that is employed by Monsanto’s Roundup Ready crops, which are located in St Louis (Missouri), typically involves inserting genes in a crop’s DNA to increase EPSP synthase production. The genes are typically derived from bacteria that have been infected by plants.

The plant can withstand the effects of glyphosate because of the extra EPSP synthase. ラウンドアップ Biotechnology labs have tried using plant genes to boost EPSP synthase activity. This was done in part to exploit a loophole within US law that allows regulatory approval of organisms containing transgenes which have not come from pests of bacteria.

There aren’t many studies that have examined whether transgenes , such as those that confer glyphosate resistance could — after they become wild or weedy relatives via cross-pollination — make those plants more competitive in survival and reproduction. “The traditional expectation is that any transgene can cause disadvantages in the wild, in the absence of any selection pressure because the additional machinery could lower the fitness,” says Norman Ellstrand an expert in plant genetics at the University of California in Riverside.

Lu Baorong of Fudan University in Shanghai is now challenging that view.ラウンドアップ/?dispNo=&codeSearch=0&searchFirst=1 The study shows that glyphosate resistance even when not applied to a weedy type of rice crop can give a significant health boost.

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

The group then allowed the offspring of cross-breeding to cross-breed with one other to produce second-generation hybrids. They were identical genetically apart from the number of EPSP synthase genes they had. The researchers found that the hybrids that had greater than one copy 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 Researchers also found that transgenics had higher rates of flowering, more flowers and 48 to 125 percent more seeds per plant than nontransgenics.

Lu believes that making the weedy rice more competitive may cause more problems for farmers across the world whose fields are infested with the pest.

Brian Ford-Lloyd is Brian Ford-Lloyd is a UK plant geneticist who states, “If the EPSP synthase gene gets in the wild rice species, their genetic diversity would be at risk, which is crucial because the genotype that has transgene has a higher level of competition than the standard species.” “This is one of the clearest examples of extremely plausible damaging consequences [of GM crops on the environment.”

The public belief that genetically-modified crops that contain additional copies of their genes are safer is questioned by this study. Lu states that the study “shows that this isn’t always the case”.

Some researchers believe this finding needs to be reviewed in light of future regulation of crops that have been genetically modified. Ellstrand believes that biosafety laws may be relaxed because we have a great level of satisfaction from the two decades of genetic engineering. “But the study proved that the new technologies still require careful evaluation.”