Plants in the wild could be given resistance to herbicides.
Weedy rice is able to pick up transgenes from genetically modified crops through cross-pollination. Credit: Xiao Yang
One of the most common methods used to make crops more resistant to herbicides was shown to be superior over weedy forms of rice. This suggests that the benefits of this modifications could extend beyond the confines of farms into the wild.
A variety of varieties of crops are genetically modified to be resistive to the glyphosate. Roundup was the first herbicide to be sold. This allows farmers to eradicate the weeds that grow in their fields without harming their crops.
Glyphosate slows the growth of plants by blocking an enzyme known as EPSP synthase, which is responsible for the production of specific amino acids as well as other molecules that make up approximately 35% of the plant’s mass. The technique of genetic modification, which is used by Monsanto’s Roundup Ready crops, which are located in St Louis (Missouri), typically involves inserting genes in the DNA of the crop to increase EPSP synthase production. The genes are usually derived from bacteria that cause disease in the plants.
The plant can withstand the adverse effects of glyphosate due to the addition of EPSP synthase. Biotechnology labs also have tried to create EPSP-synthase that is more plant-based than bacteria by utilizing genes from plants. This was partly made to make use of an inconsistency found in US law which allows regulatory approval for species that are not derived from bacterial parasites.
There aren’t many studies that have examined whether transgenes such as ones that confer resistance to glyphosate are able to — once they get into wild or weedy relatives via cross-pollination, make plants more competitive in terms of survival and reproduction. “The common belief is that any transgene will confer disadvantage in the wild in 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 discovered that glyphosate resistance gives significant fitness benefits to the weedy version of the popular rice plant Oryza Sativa.
ラウンドアップ 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 except in the amount of copies of the gene that encodes EPSP synthase. Likely, the ones who had more copies expressed higher levels of the enzyme, and produced more amino acid tryptophan than their unmodified counterparts.
Researchers also discovered that transgenic hybrids were photogenic, had more seeds per plant, and produced 48 to 125% higher yields of seeds than the non-transgenic varieties.
Making the weedy rice more competitive could increase the issues it creates for farmers around the world where plots are ravaged by pests, Lu says.
“If the EPSP-synthase gene is introduced into the wild rice plant, their genetic diversity, which is vital to preserve, could be threatened because the genotype with the transgene would outcompete the normal species,” Brian Ford-Lloyd an expert in plant genetics at the University of Birmingham, UK. This is one of the most clear examples of plausible negative effects [of GM crop] on the environment.”
The public belief that genetically-modified crops with additional copies their genes are more secure is questioned by this study. Lu states that “our study is not proving that this is the case.”
Researchers have concluded that these findings should prompt an overhaul of how genetically modified crops are regulated in the near future. “Some people are now claiming that biosafety regulation can be relaxed because we have an incredibly high level of confidence with two decades of genetic engineering,” Ellstrand says. ラウンドアップ The study doesn’t prove that new products are safe.