Notes

The advantages of genetically modified crops over weeds

Wild plants may be capable of resisting herbicides.

Credit Xiao Yang
The use of genetic modification of crops to make them resistant to herbicides has been widely utilized to provide advantages to species of rice that are weedy. This suggests that the genetic modification may also have potential to impact wild animals.

A variety of crop varieties are genetically modified so that they can resist glyphosate. The herbicide was initially sold under the tradename Roundup. ラウンドアップ This resistance to glyphosate allows farmers to wipe out most weeds from the fields without harming their crop.

Glyphosate slows the growth of plants by blocking an enzyme referred to as EPSP synthase. This enzyme is involved in the production of certain amino acids and other molecules that comprise as much as 35% of the plant's mass. The technique of genetic modification that is employed by Monsanto's Roundup Ready crops, which are located in St Louis (Missouri), typically involves inserting genes into a crop's DNA to increase EPSP synthase production. ラウンドアップ Genes are typically obtained from bacteria that cause disease to the crops.

ラウンドアップ This additional EPSP synthase enables the plant to withstand the effects of glyphosate. Biotechnology labs attempted to utilize plant genes to boost EPSP synthase activity. https://search.rakuten.co.jp/search/mall/%E3%83%A9%E3%82%A6%E3%83%B3%E3%83%89%E3%82%A2%E3%83%83%E3%83%97+%E3%83%9E%E3%83%83%E3%82%AF%E3%82%B9%E3%83%AD%E3%83%BC%E3%83%89/ This was partly to exploit a loophole within US law that permits 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 glyphosate-resistant genes can -- once introduced to weedy or wild plants by cross-pollination -- enhance the competition of plants in survival, reproduction and growth. "The traditional expectation is that any sort of transgene could cause disadvantage in the wild in absence of pressure to select, because the additional machinery could decrease the fitness of the plant," says Norman Ellstrand who is a plant geneticist at the University of California in Riverside.

A new study, led by Lu Baorong, an ecologist from Fudan University in Shanghai, disproves that belief It reveals that the weedy form of the common rice crop, Oryza sativa has a significant fitness boost from resistance to glyphosate, even when glyphosate is not used.

The study was published in 1. ラウンドアップ Lu and his collaborators have genetically modified rice to increase its EPSP synthase expression , and then crossed it with a weedy cousin.

The group then permitted the offspring from cross-breeding to cross-breed to create second generation hybrids. They were genetically identical with the exception of the amount of EPSP synthase genes they had. As one would expect, hybrids that had more copies of the gene were more likely to produce more tryptophan as well as have greater levels of enzymes than the unmodified hybrids.

Researchers also discovered that transgenic hybrids were more photogenic, they produced more plants per plant and yielded 48-125 percent more seeds than non-transgenic varieties.

https://www.nissanchem.co.jp/news_release/news/n2020_01_23.pdf Lu states that making weedy crops more competitive may create more difficulties for farmers across the world whose crops are infected by the insect.

"If the EPSP-synthase gene gets in the wild rice species, their genetic diversity, which is really essential to protect, could be threatened because the genotype with the transgene would outcompete the natural species" Brian Ford-Lloyd an expert in plant genetics at the University of Birmingham, UK. "This is one illustration of the most plausible and damaging effects of GM crops on the environment."

ラウンドアップ Many people believe that plants with genetically modified genes containing more copies of their own genes than those from microorganisms are safe. This is not supported by the study. Lu states that his study does not support this view.

Researchers have said that this discovery calls for a review of the regulations for the future on genetically modified crops. Ellstrand believes that some believe that biosafety regulations could be relaxed because we've had more than two years of genetic engineering. "But the study demonstrates that novel products still need careful examination."


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