Genetically modified plants are more efficient than the weeds


Wild plants might be capable of resisting herbicides.

Credit Xiao Yang
It has been demonstrated that a genetic modification technique is extensively used to create crops that are herbicide-resistant confers advantages on the rice that is weedy. This finding suggests that these modifications may be detrimental to the natural environment beyond farms.

https://www.komeri.com/disp/CKmSfGoodsPageMain_001.jsp?GOODS_NO=1013169 A variety of crops have been genetically altered so that they can ward off the glyphosate. The herbicide was initially available under the trade name Roundup. Farmers can eliminate most herbicides from their fields by using glyphosate and not harm their crops due to this resistance.

https://pesticide.maff.go.jp/agricultural-chemicals/details/14360 Glyphosate prevents plant growth by stopping EPSP synthase (an enzyme that plays a role in the formation of amino acids, and other molecules). This enzyme could comprise as much as 35 percent or more of a plant's total mass. The technique of genetic modification, which is used by Monsanto's Roundup Ready crops, which are based in St Louis (Missouri), typically involves inserting genes in a crop's DNA to increase EPSP synthase production. The genes typically come from bacteria that have affected plants.

The plant can withstand the effects of glyphosate because of the extra EPSP synthase. Biotechnology laboratories are trying to utilize genes from plants rather than bacteria to boost EPSP synthase. This is partly because the US law permits regulatory approval to allow organisms that have transgenes to be accepted.

There aren't many studies that have examined the possibility that transgenes like those that confer glyphosate resistance could -- after they become wild or weedy relatives via cross-pollination -- make those plants more competitive in survival and reproduction. "The conventional belief is that any transgene will confer disadvantage in the wild, in the absence of any selection pressure because the extra machinery would reduce the fitness," says Norman Ellstrand, a plant geneticist at the University of California in Riverside.

Lu Baorong (an ecologist at Fudan University, Shanghai) has since challenged this view. It shows that resistance to glyphosate provides significant benefits to fitness for a weedy rice crop called Oryza Sativa even when not in use.

Lu and his coworkers genetically modified the cultivated Rice species to express the EPSP synthase. Then, they crossed-bred it to a marijuana-producing parent.

The team allowed the offspring of cross-breeding to cross-breed to create second generation hybrids.https://www.komeri.com/disp/CKmSfGoodsPageMain_001.jsp?GOODS_NO=1713321 They were identical genetically with the exception of the amount of EPSP synthase genes they had. It was expected that those with more copies of the gene had more enzyme activity and more amino acid tryptophan in comparison to the unmodified counterparts.

Researchers also found that transgenics had higher rates, had more flowers and 48-125percent more seeds/plant than nontransgenics.

Lu believes that making rice that is weedy less competitive can make it harder for farmers whose plots are affected by pests.

Brian Ford-Lloyd (a UK plant geneticist) claims that if the EPSP-synthase genes gets into wild rice species, their genetic diversity which is so important to conserve could be at risk. The transgene will be more competitive than regular species. "This is an example of the most likely and harmful negative effects of GM crops on the environment."

This study challenges popular notion that genetically modified plants with additional copies of their own genes are safer than the ones that have the genes of microorganisms. Lu says that Lu's research does not contradict this view.

The research results call for a rethinking of future regulation of genetically modified crops, some researchers say. Ellstrand thinks that biosafety laws can be relaxed since we can benefit from a high degree of security from two decades of genetic engineering. The study found that any new products need to be carefully evaluated.