Auto Draft

The wild plants may possess an herbicide resistance advantage.

Credit Xiao Yang
A well-known method of genetic modification of crops that make them herbicide-resistant has been proven to provide advantages to weedy varieties rice even when herbicide isn’t in use. These results suggest that such modifications can have a broad spectrum of effects that extend beyond farms and into the wild.

A range of crop varieties have been modified genetically to make them resistant to Roundup herbicide glyphosate. Farmers are able to eliminate weeds in their fields using glyphosate, without harming their crops due to this resistance.

Glyphosate is a plant-killer by inhibiting EPSP synase which is an enzyme that plays a role in the creation of amino acids, as well as other chemical compounds that make up about 35% of plants’ mass. Genetic modification, for instance, the Roundup Ready crops manufactured by Monsanto in St. Louis, Missouri, involves inserting genes to a crop’s genetic code to increase EPSP production. Genes are usually derived from bacteria that infects the crops.

This extra EPSP synthase enables the plant to withstand the effects from glyphosate. ラウンドアップ Biotechnology laboratories are looking to utilize genes that come from plants instead of bacteria to increase EPSP synthase. This is mainly due to the US law allows approval by the regulatory authorities to allow organisms with transgenes to be approved.

A few studies have looked into whether transgenes , such as those that confer glyphosate resistance can — once they are wild or weedy relatives via cross-pollination -make plants more competitive for survival and reproduction. ラウンドアップ Norman Ellstrand is a University of California Riverside plant geneticist. “The assumption is that any kind of transgene can cause disadvantage in the wild, in the absence of select pressure, because it would reduce fitness,” Ellstrand said.

However, a new study conducted by Lu Baorong, an ecologist from Fudan University in Shanghai, disproves that belief It reveals that the weedy version of the popular rice plant, Oryza sativa has an important boost in fitness due to glyphosate resistance, even when glyphosate has not been used.

In the study which was published this month in New Phytologist 1, Lu and his colleagues modified the genetics of the rice plant to overexpress the species’ own EPSP synthase and cross-bred the altered rice with a weedy ancestor.

The team then allowed the offspring of cross-breeding to cross-breed with each other to create second generation hybrids.,2084008038,2084034075&rewrite_ok_wand_re_search=1 They were genetically identical except for the amount of EPSP synthase genes they had. As one would expect, more copies resulted in higher levels of enzyme as well as more tryptophan than the unmodified counterparts.

Researchers also discovered that the hybrids with transgenic genes had greater rates of photosynthesis, grew more shoots and flowers and produced 48 to 125 percent more seeds per plant than non-transgenic hybrids -without the use of glyphosate.

Lu believes that making the weedy rice more competitive might make the problem worse for the farmers around the globe whose fields are infested with the pest.

ラウンドアップ “If the EPSP-synthase gene is introduced into the wild rice plant, their genetic diversity, which is important to conserve is at risk because the genotype with the transgene would outcompete the normal species,” says Brian Ford-Lloyd, a plant geneticist at the University of Birmingham, UK. “This is one of the most clear instances of the extremely damaging impacts (of GM crops on the environment.”

There is a popular belief that genetically engineered crops that have more copies or microorganisms’ genes are more secure than those containing only their own genes. “Our study shows that this is not necessarily the case,” says Lu.

Researchers believe this discovery calls for a reconsideration of the regulation for the use of genetically modified plants. Ellstrand thinks that biosafety laws could be relaxed as we can benefit from a high degree of satisfaction from the two decades of genetic engineering. “But the study still suggests that new products need careful analysis.”