Auto Draft

The wild plants could have the advantage of resistance to herbicides.

Credit: Xiao Yang
One common genetic-modification method used to make crops more resistant to herbicides has been shown to be superior over the weedy varieties of rice. This suggests that the genetic modification may also have potential to have an impact on wild animals.

A variety of crops has been modified genetically so that they become resistant to Roundup herbicide glyphosate. This resistance to glyphosate allows farmers to eradicate the majority of plants without harming their crop.

Glyphosate slows the growth of plants by inhibiting EPSP synthase (an enzyme that is involved in the production of specific amino acids, and other molecules). This enzyme can make up as much as 35 percent or more of the plant’s total mass. The technique of genetic modification is employed, for example, in Roundup Ready plants made by Monsanto, a biotechnology company located in St Louis, Missouri. It involves inserting genes into the genome of a crop to boost EPSP synthase synthase synthase production. ラウンドアップ Genes are usually derived from bacteria that infect crops.

The extra EPSP synase makes it possible for plants to resist the harmful effects of glyphosate. Biotechnology labs have also attempted to use genes from plants rather than bacteria to increase EPSP-synthase levels, in part to exploit the loophole within US law that facilitates approval by regulators of organisms that have transgenes that are not made from bacterial pests.

A few studies have explored the possibility that transgenes, like those that confer resistance glyphosate, can make plants more resilient in their survival and reproduction after they cross-pollinate with weedy or wild species. Norman Ellstrand is a University of California Riverside plant geneticist. “The assumption is that any kind of transgene will cause disadvantage in the wild in the absence of pressure to select, due to the fact that it reduces fitness,” Ellstrand said.

Lu Baorong (an ecologist at Fudan University, Shanghai) has now challenged that view. It has proven that glyphosate resistance can give an impressive fitness boost to a weedy rice crop known as Oryza Sativa even when it is not used. Lu and coworkers modified the cultivars of rice to improve its EPSP synthase. The modified rice was crossed with a wild-type relative.

The group then permitted the offspring from cross-breeding to cross-breed with each other to create second generation hybrids. They were identical genetically with the exception of the amount of EPSP synthase genes they had. As was expected, those who had more copies had more enzyme activity and more amino acid tryptophan in comparison to the unmodified counterparts.

Researchers also discovered that transgenic hybrids are more photogenic, had more seeds per plant, and produced 48 to 125 percent higher yields of seeds than the non-transgenic varieties.

Lu states that making weedy grains more competitive can create more difficulties to farmers all over the world whose crops are affected by the insect.

Brian Ford Lloyd, a UK plant scientist, stated that the EPSP Synthase gene is able to get into wild rice species. This would threaten the genetic diversity of their species, which is very crucial. “This is one the most clear examples of highly plausible harmful consequences (of GM crops] upon the natural environment.”

The public believes that genetically modified plants that have more than one copy of their genes than those from microorganisms are safer. This is not supported by the study. Lu states that his study does not support this view.

Certain researchers believe that this finding requires a review of the future regulation of crops that have been genetically modified. Ellstrand says that “some people believe that biosafety regulations could be relaxed due to our an incredibly comfortable relationship with genetic engineering over the last two decades.” The study found that any new products must be evaluated carefully.