Notes

Genetically modified crops have more benefits than the weeds

Herbicide resistance might confer an advantage on plants in the wild.

Weedy rice can pick up transgenes from genetically modified crops through cross-pollination. Credit: Xiao Yang
A common method of genetic modification employed to make crops resistant to herbicides has been shown to offer advantages over rice varieties that are weedy. This indicates that these changes could affect the environment beyond farms.

Many cultivars have been genetically modified in order to ward off the effects of glyphosate. The herbicide was initially sold under the tradename Roundup. This resistance to glyphosate permits farmers to get rid of weeds without causing any damage to their crops.

Glyphosate inhibits growth of plants by inhibiting EPSP synthase (an enzyme that plays a role in the creation of certain amino acids and other molecules). The enzyme can make up as much as 35% or more of a plant’s total mass. Genetic modification employed by Monsanto's Roundup Ready crops, which are based in St Louis (Missouri), typically involves inserting genes into the DNA of a plant to boost EPSP synthase production. The genes are often derived from bacteria that have infected the plant.

The extra EPSP synthase allows the plant to resist the effects of glyphosate. Biotechnology labs have also tried to create EPSP-synthase that is more plant-based than bacteria using genes from plants. ラウンドアップ ラウンドアップ This was partly used to take advantage of a loophole found in US law that allows regulatory approval for organisms that aren't derived from bacterial parasites.

A few studies have looked into the possibility that transgenes like ones that confer resistance to glyphosate could -- after they get into weedy or wild relatives through cross-pollination, make plants more competitive in survival and reproduction. Norman Ellstrand, a University of California plant geneticist says that without competition, any kind of transgene is likely to confer disadvantage on wild plants. The additional machinery could lower fitness.

But now a study led by Lu Baorong, an ecologist from Fudan University in Shanghai, disproves that belief: it shows that a weedy version of the popular rice crop, Oryza sativa is given a significant fitness boost from the resistance to glyphosate even when glyphosate has not been applied.

ラウンドアップ Lu and coworkers modified the cultivated rice species to enhance its EPSP synthase. The modified rice was crossed with a wild relative.

The team let the offspring of crossbreeding to cross-breed with one other to produce second-generation hybrids. They were genetically identical apart from the number of EPSP synthase genes they had. As expected, the ones with more copies of the gene had more enzyme activity and more amino acid tryptophan when compared to their counterparts that were not modified.

Researchers also discovered that transgenics had higher rates, had more flowers and 48 to 125 percent more seeds per plant than nontransgenics.

Lu believes that making weedy, aggressive rice more competitive could make it harder for farmers to recover from the harm caused by this pest.

ラウンドアップ Brian Ford-Lloyd, Brian Ford-Lloyd is a UK plant geneticist and states, "If the EPSP synthase gene is introduced into wild rice species their genetic diversity will be at risk, which is significant because the genotype with transgene outcompetes the normal species." https://mujin-heri.jp/yakuzai/js-55.html "This is one of the clearest instances of the extremely damaging consequences (of GM crops on the environment."

The research also challenges the idea that crops with genetically modified genes containing extra copies of their genes are more safe than those containing microorganism genes. Lu claims that the study doesn't support this belief.

According to some researchers this finding suggests that future regulation of genetically engineered crops should be reconsidered. Ellstrand states "Some people believe that the biosafety regulations should be looser." Ellstrand adds: The study doesn't prove that novel products are safe.

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