Notes

Genetically modified plants are more efficient than weeds

In nature, resistance to herbicides could confer advantages to plants.

Credit: Xiao Yang
One of the most common methods that makes crops resistant to herbicides has been shown to have advantages over rice varieties that are weedy. The results indicate that such modification could have positive effects on wild rice varieties, as well as the crops.

There are many kinds of plants are genetically modified to be resistive to the glyphosate. ラウンドアップ Roundup was the first herbicide that was marketed. Farmers are able to eliminate weeds from their fields with this glyphosate resistance , without damaging their crops.

Glyphosate prevents plant growth by blocking EPSP synthase (an enzyme involved in the production of specific amino acids and other molecules). The enzyme can comprise as much as 35 percent or more of a plant’s total mass. Genetic modification -- used, for instance, in Roundup Ready crops made by the biotech giant Monsanto, based in St Louis, Missouri -usually involves inserting genes into the crop's genome to boost EPSP-synthase production. Genes typically come from bacteria that cause disease to plants.

The plant can resist the adverse effects of glyphosate due to its extra EPSP-synthase. Biotechnology labs tried to use genes from plants to boost EPSP synthase activity. This was partly to make use of a loophole that is in US law that permits the regulatory approval of transgenes contained in organisms that are not derived from bacteria pests.

https://www.agriz.net/fs/nouki/560101997001 Few studies have explored the possibility that transgenes that confer glyphosate tolerance can -- once they become weedy , or wild relatives via cross-pollinating -can boost the plant's survival and reproduce. ラウンドアップ Norman Ellstrand of the University of California, Riverside, stated that the conventional expectation was that any transgene will be detrimental to nature if there is no selection pressure. This is due to the fact that any additional machinery could reduce the fitness.

Lu Baorong (an ecologist at Fudan University, Shanghai) has now questioned that opinion. It has proven that resistance to glyphosate can provide an impressive fitness boost to a weedy rice crop known as Oryza sativa even when it is not being used.

In the study published this month in New Phytologist 1, Lu and his colleagues modified the genetics of the rice cultivar to enhance the species' own EPSP synthase and cross-bred the modified rice with a weedy relative.

The team let the offspring of crossbreeding to cross-breed with each other to produce second-generation hybrids. They were genetically identical except for the amount of EPSP synthase genes they carried. The hybrids that had more copies of the gene were more likely to produce more tryptophan and have greater levels of enzymes over their counterparts that were not modified.

Researchers also discovered that the hybrids with transgenic genes had greater rates of photosynthesis, produced more flowers and shoots and produced 48-125% more seeds per plant than non-transgenic hybrids -- in the absence of glyphosate.

Lu believes making weedy, invasive rice more competitive may hinder farmers to recoup the damage caused by this bug.

ラウンドアップ Brian Ford Lloyd, a UK plant scientist, said that the EPSP Synthase gene may be introduced into wild rice species. This could threaten their genetic diversity, which is very important. ラウンドアップ "This is one the most evident instances of the highly probable negative impacts (of GM crops] upon the natural environment."

The study also challenges the public belief that crops modified genetically carrying extra copies of their own genes are safer than those containing genes from microorganisms. Lu claims that the study doesn't support this notion.

Some researchers believe this finding needs to be reviewed in light of future regulation of crops that have been genetically modified. "Some individuals are suggesting that biosafety regulations can be eased because we've reached an extremely high level of satisfaction with two decades of genetic engineering," says Ellstrand. "But the research shows that novel products still need cautious examination."


My Website: https://search.yahoo.co.jp/video/search?rkf=2&ei=UTF-8&fr=wsr_gvu&p=%E3%83%A9%E3%82%A6%E3%83%B3%E3%83%89%E3%82%A2%E3%83%83%E3%83%97