Notes

Benefits of genetically modified plants over the weeds

The wild plants may possess an herbicide resistance advantage.

Weedy rice may take on transgenes from genetically modified rice by cross-pollinating. Credit: Xiao Yang
A well-known method of genetic modification of crops that make them herbicide-resistant has been proven to provide advantages to the weedy varieties of rice even when herbicide isn't in use. This suggests that the genetic modification could also have potential to impact wild animals.

Several types of crops have been genetically modified to be intolerant to glyphosate, a herbicide that was first advertised under the brand name Roundup. This glyphosate-resistant crop allows farmers to eradicate the majority of weeds from the fields without causing damage to their crops.

Glyphosate inhibits growth of plants by stopping EPSP synthase (an enzyme involved in the formation of amino acids as well as various other molecules). This enzyme could make up as much 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 in a plant to boost EPSP synthase production. Genes usually come from bacteria that infects plants.

ラウンドアップ is able to withstand the effects of glyphosate because of the additional EPSP synthase. Biotechnology labs have also tried to create EPSP-synthase that is more plant-based than bacteria using genes from plants. This was made to make use of the loophole in US law, which permits regulatory approval for species that are not derived from bacteria.

A few studies have looked into the possibility that transgenes that confer tolerance could -- after they become weedy , or wild relatives via cross-pollinating -enhance the plant's longevity and reproductive. "The conventional belief is that any sort of transgene will confer disadvantage in the wild in the absence of any selection pressure because the extra machinery would lower the fitness," says Norman Ellstrand an expert in plant genetics at the University of California in Riverside.

Lu Baorong of Fudan University in Shanghai is now challenging that view. https://www.dtomarmaris.org/auto-draft-201/ shows that glyphosate resistance even when not applied to the weedy variety of the rice crop can provide a significant health boost.

https://www.martinbraunusa.com/what-is-the-story-behind-how-roundup-ready-or-roundup-get-their-names/ and his colleagues have genetically altered the cultivated rice species to express its EPSP synthase, and then crossed-bred it to an plant that was weedy.

The team let the offspring of crossbreeding to cross-breed with one other to produce second-generation hybrids. They were genetically identical with the exception of the amount of EPSP synthase genes they carried. As expected, those who had more copies expressed higher levels of the enzyme, and produced more of the amino acid tryptophan than their unmodified counterparts.

https://www.anochords.org/auto-draft-133/ found that transgenic hybrids were photogenic, had more seeds per plant, and produced 48 to 125 percent higher yields of seeds than the non-transgenic varieties.

Lu believes that making the rice weedy less competitive could make it more difficult for farmers who have their land infested by pests.

Brian Ford-Lloyd from the University of Birmingham, UK, says "If the EPSP synthase gene is introduced to wild rice species, their genetic variety is crucial in conserving it, could be threatened because it would surpass the regular varieties." "This is an instance of the most plausible and damaging impacts of GM crops on the environment."

This study challenges perception that genetically modified crops carrying additional copies of their own genes are safer than the ones that have the genes of microorganisms. Lu claims that the study doesn't support this belief.

Researchers believe that their findings require an overhaul of the way that genetically modified crops will be regulated in the near future. Ellstrand says "Some people think that regulation of biosafety should be looser." Ellstrand says: The study doesn't prove that the new products are secure.


Homepage: https://www.dtomarmaris.org/auto-draft-201/