Notes

Genetically modified crops offer advantages to weeds

Wild plants could be capable of resisting herbicides.

Credit Xiao Yang
A genetic-modification technique used widely to produce crops that are herbicide-resistant has been proven to provide advantages to an invasive form of rice even in the absence of the herbicide. The results indicate that such modification may be able to have positive effects on wild rice varieties, as well as the crops.

There are many varieties of crops have been genetically altered to be resistive to the glyphosate. Roundup was the first herbicide to be sold. This resistance to glyphosate allows farmers to eradicate the majority of weeds from the fields without causing damage to their crops.

Glyphosate prevents plant growth by inhibiting EPSP synthase (an enzyme that is involved in the formation of amino acids as well as other molecules). This enzyme can be as large as 35% or more of a plant’s total mass. The genetic modification method used in Roundup Ready crops by Monsanto (based in St Louis in Missouri), involves inserting genes into the crop to increase EPSP synthase's output. The genes are typically derived from bacteria infected with plants.

The plant can withstand the effects caused by glyphosate because it has an additional EPSP-synthase. Biotechnology labs are also attempting to make use of genes from plants rather than bacteria to increase EPSP synthase. This is mainly due to the US law permits regulatory approval that allows organisms that have transgenes to be accepted.

A few studies have explored whether transgenes, such as those that confer resistance glyphosate, could make plants more resilient in survival and reproduction once they cross-pollinate with weedy or wild species. ラウンドアップ "The common belief is that any transgene could cause disadvantage in the wild in absence of selection pressure, due to the fact that any additional machinery will lower the fitness," says Norman Ellstrand, a plant geneticist at the University of California in Riverside.

Lu Baorong is an ecologist in Fudan University Shanghai. His study shows that glyphosate resistance provides a significant fitness benefit, even though it's not applied.

Lu and his colleagues modified the cultivars of rice to produce more EPSP synthase. They also crossed the modified rice with a weedy related. Their research was published in NewPhytologist 1.

ラウンドアップ The group allowed the offspring of cross-breeding to mix with each other, creating second-generation hybrids that are genetically identical with each other except for the number of copies of the gene encodes EPSP synase. Like one might expect, the higher number of copies of the gene produced higher levels enzyme as well as more tryptophan than their unmodified counterparts.

Researchers also found that plants with transgenic genes showed higher rates of photosynthesis as well as produced more flowers and produced 48-125percent less seeds per plant than the nontransgenic hybrids. This was despite the fact that glyphosate wasn't present.

ラウンドアップ Lu suggests that making rice that is weedy more competitive could make the problem worse for farmers across the world who's 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, then their genetic diversity that is essential to protect could be at risk. The transgene would outcompete natural species. "This is one the most clear instances of the highly probable negative impacts of GM crops] upon the environment."

https://search.rakuten.co.jp/search/mall/ラウンドアップ+マックスロード/ Many people believe that genetically modified plants that have more copies of their own genes than those from microorganisms are safer. This notion is also challenged by this study. ラウンドアップ Lu states that his research does not contradict this belief.

According to some scientists, the finding suggests that the future regulation of genetically engineered plants should be reviewed. "Some people are now suggesting that biosafety regulation can be relaxed because we have an extremely high level of satisfaction with two years of genetic engineering" Ellstrand says. This study isn't proof that new products are safe.


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