Notes

Genetically modified crops provide advantages to weeds

In nature, herbicide resistance could confer advantages to plants.

Weedy rice can absorb transgenes derived from genetically modified crop rice through cross-pollination. Credit: Xiao Yang
It has been established that a genetic modification technique, which is widely used to make crops herbicide-resistant, confers advantages on the rice that is weedy. This suggests that these changes could have an impact on the environment beyond farms.

Many crop varieties have been genetically modified in order to resist the effects of glyphosate. The herbicide was initially offered under the trade name Roundup. The resistance to glyphosate permits farmers to eradicate most weeds without causing any damage to their crops.

Glyphosate can inhibit plant growth by blocking EPSP synase which is an enzyme involved in the production amino acids, as well as other chemical compounds that make up about 35% of the plant's mass. Genetic modification, for instance, the Roundup Ready crops manufactured by Monsanto in St. Louis, Missouri, involves inserting genes into the genetic code to boost EPSP production. Genes typically come from bacteria that cause disease to plants.

ラウンドアップ 英語 The added EPSP synthase lets the plant withstand the effects of glyphosate. Biotechnology laboratories are trying to use genes that come from plants instead of bacteria to increase EPSP synthase. This is mainly due to the US law allows for regulatory approval to allow organisms with transgenes to be recognized as acceptable.

A few studies have explored whether transgeneslike those that confer resistance to glyphosate, can increase the resilience of plants in survival and reproduction once they cross-pollinate with wild or weedy species. "The common belief is that any sort of transgene could cause disadvantage in the wild, in the absence of selection pressure, because the additional machinery could decrease the fitness of the plant," says Norman Ellstrand an expert in plant genetics at the University of California in Riverside.

Lu Baorong, an ecologist from Fudan University in Shanghai has revised that opinion. ラウンドアップ He has discovered that resistance to glyphosate provides a significant fitness lift to the weedy variant of the standard rice crop Oryza Sativa.

Their study was published in 1. Lu and his collaborators have genetically modified rice to boost its EPSP synthase expression , and then crossed it with a weedy relative.

https://search.kakaku.com/%8F%9C%91%90%8D%DC%20%83%89%83E%83%93%83h%83A%83b%83v%83%7D%83b%83N%83X%83%8D%81%5B%83h/ The group then allowed cross-bred offspring to breed with each other, resulting in second-generation hybrids genetically identical to one another with the exception of the number of copies of gene that encodes EPSP synthase. It was expected that those with more copies of the gene had greater levels of enzymes and produced an increased amount of amino acid tryptophan compared to their unmodified counterparts.

Researchers also discovered that transgenic hybrids were photogenic, had more seeds per plant and had 48-125% higher yields of seeds than varieties that were not transgenic.

Lu believes that making the rice weedy less competitive might make it more difficult for farmers who have their plots affected by the pest.

Brian Ford-Lloyd is a UK plant geneticist and states, "If the EPSP synthase gene gets in the wild rice species their genetic diversity could be at risk, which is important because the genotype with transgene outcompetes the normal species." "This is a prime illustration of the most likely and harmful effects of GM crops on the environment."

The research also challenges the idea that genetically modified crops containing extra copies of their genes are more safe than those containing microorganism genes. Lu declares that "our study doesn't prove that this is the case."

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/ ラウンドアップ Researchers say these findings should prompt a reconsideration of the way that genetically modified crops are regulated in the near future. Ellstrand thinks that biosafety laws could be relaxed as we are able to benefit from a high degree of security from two decades of genetic engineering. "But the study shows that new products require cautious assessment."

https://www.nissanchem.co.jp/news_release/news/n2020_01_23.pdf
Homepage: https://www.nissanchem.co.jp/news_release/news/n2020_01_23.pdf