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Wild plants could be able to resist herbicides.

ラウンドアップ 互換 Credit: Xiao Yang
The use of genetic modification to make crops resistant to herbicides has been extensively utilized to provide advantages to species of rice that are weedy. These findings suggest that such modifications may have a wide range of effects beyond the farms, and possibly into the wild.

ラウンドアップ ラウンドアップ ラウンドアップ Many varieties of crops have been genetically altered to be resistive to glyphosate. Roundup was the first herbicide that was marketed. The resistance to glyphosate enables farmers to eliminate weeds without causing any damage to their crop.

ラウンドアップ Glyphosate inhibits growth of plants by blocking EPSP synthase (an enzyme involved in the production of specific amino acids as well as other molecules). This enzyme can make up as much as 35% or more of a plant’s total mass. Genetic modification is used in, for instance, Roundup Ready plants made by Monsanto Biotechnology Inc., a biotech firm that is headquartered in St Louis, Missouri. ラウンドアップ It involves inserting genes into the genome of a crop to boost EPSP synthase-synthase-production. Genes are usually derived from bacteria that cause disease to the crops.

The extra EPSP synthase helps the plant be resistant to the effects of glyphosate. Biotechnology labs are also trying to utilize genes that come from plants instead of bacteria to increase EPSP synthase. This is partly because the US law allows for regulatory approval that allows organisms with transgenes to be approved.

There aren't many studies that have examined whether transgenes that confer glyphosate tolerance could — after they become weedy or wild relatives via cross-pollinating — increase the plants' survival and reproduce. Norman Ellstrand of the University of California, Riverside, stated that the conventional expectation was that any transgene will cause disadvantage in nature when there was no pressure to select. This is due to the fact that any additional machinery could reduce the performance of the.

Lu Baorong, an ecologist from Fudan University in Shanghai has rewritten that view. He has discovered that resistance to glyphosate provides significant fitness benefits to the weedy variant of the standard rice plant Oryza Sativa.

Lu and his associates modified cultivated rice varieties to make more EPSP synthase. They also crossed the modified rice with a weedy related. Their findings were published in NewPhytologist 1.

The researchers allowed offspring of crossbreeding to crossbreed with each other, resulting in second-generation hybrids that are genetically identical to one another, except for the amount of copies the gene encodes EPSP synase. As one would expect, the higher number of copies resulted in higher levels of enzyme as well as more tryptophan than the unmodified counterparts.

Researchers also found that transgenic hybrids grew between 48-125percent more seeds per plant. They also had higher photosynthesis rates and produced more shoots than the non-transgenic varieties.

Lu believes that making weedy Rice more competitive could increase the risk for farmers across the world whose fields are being ravaged by the pest.

Brian Ford-Lloyd (a UK plant geneticist) says that if the EPSP-synthase genes are introduced into wild rice species, their genetic diversity that is essential to protect could be endangered. The transgene will outcompete normal species. This is one of the most clear examples of likely negative effects of GM crop on the environment."

The public believes that genetically modified plants containing more copies of their own genes than microorganisms are safer. This belief is however questioned by the study. "Our study shows that this is not necessarily the case," says Lu.

Researchers believe this discovery requires review of the regulations for the future on the use of genetically modified plants. Ellstrand believes that biosafety regulations may be relaxed because we benefit from a high degree of comfort from two decades worth of genetic engineering. "But this study has shown that novel products still need to be evaluated with care."