Notes

Benefits of genetically modified plants over weeds

In the wild, plants can be treated with herbicides.

Credit: Xiao Yang
Genetic modification to create crops resistant to herbicides has been extensively employed to create advantages for species of rice that are weedy. This suggests that the genetic modification could also have potential to impact wild animals.

A variety of varieties of crops are genetically engineered to be resistant to the glyphosate. The herbicide, first known as Roundup and then introduced to the market in 1996 under the trade name Roundup. This glyphosate resistance enables farmers to wipe out most herbicides in their fields without causing damage to their crop.

Glyphosate blocks the enzyme EPSP synthase that is responsible for the creation of specific amino acids and various other molecules. It can also hinder the growth of plants. Genetic modification is used for instance, in Roundup Ready plants made by Monsanto Biotechnology Inc., a biotech firm that is headquartered in St Louis, Missouri. It involves inserting genes into the genome of the crop to increase EPSP synthase-synthase production. Genes are usually derived from bacteria that infects the crops.

This additional EPSP synthase enables plants to counteract the effects of glyphosate. Biotechnology laboratories are attempting to utilize genes that come from plants instead of bacteria to boost EPSP synthase. This is partly because the US law permits regulatory approval to allow organisms that carry transgenes to get approved.

There aren't many studies that have examined the possibility that transgenes like glyphosate-resistant genes can -- once introduced to wild or weedy plants via cross-pollination make these plants more competitive in terms of survival, reproduction and growth. "The traditional expectation is that any transgene will confer disadvantage in the wild, in the absence of selection pressure, because the additional machinery could lower the fitness," says Norman Ellstrand who is a plant geneticist at the University of California in Riverside.

Lu Baorong from Fudan University in Shanghai is currently challenging this view. The study shows that resistance to glyphosate even when it is not applied to a weedy varieties of the rice crop could provide a substantial health benefit.

Lu and his colleagues modified cultivated rice varieties to increase the production of EPSP synthase. They also crossed the modified rice with a weedy-related. Their findings were published in NewPhytologist 1..

The team then allowed the breeding offspring from the cross to mix with one another, resulting in second-generation hybrids genetically identical to one another apart from the number of copies of gene encoding EPSP synthase. It was expected that those with more copies had more enzyme activity and an increased amount of amino acid tryptophan in comparison to their counterparts that were not modified.

Researchers also discovered that transgenic plants showed higher rates of photosynthesis as well as produced more flowers and produced 48 to 125 percent fewer seeds per plant than non-transgenic hybrids. This was in spite of the fact that glyphosate was not present.

Lu believes that making the rice weedy less competitive could make it harder for farmers who have their land invaded by the pest.

"If the EPSP-synthase genes are introduced into the wild rice species their genetic diversity, which is essential to protect is at risk because the transgene's genetic make-up will outcompete the normal species," says Brian Ford-Lloyd an expert in plant genetics at the University of Birmingham, UK. "This is among the clearest examples of extremely plausible damaging consequences [of GM crops on the environment."

The research also challenges the notion that genetically modified crops containing additional copies of their genes are more safe than those that contain microorganisms' genes. "Our study proves that this isn't always the case," says Lu.

https://www.asian-tapas.com/what-happened-to-roundup-ready-and-roundup-develop/ say this discovery calls for a review of the regulations for the future on genetically modified crops. "Some people are now claiming that biosafety regulations can be relaxed because we have an incredibly high level of confidence with the two decades of genetic engineering," Ellstrand says. "But the research still indicates that innovative products require careful evaluation."


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