GM Crops Can Potentially Pass On Transgenes To Natural Crops Through Cross Pollination

A recent study has shown that GM crops may pass on certain properties to plants under the same family through cross pollination. Researchers found out that genetically modifying a cultivated rice crop can transfer certain properties to a weedy relative to give it a fitness boost. The fitness boost gave the weedy relative become more competitive in their environment, possibly causing problems for cultivated rice farmers. The study is published in the journal New Phytologist.

Previous studies indicate that GM crops or transgenes will not confer any advantage to crops in the wild. But a new study tries to challenge that notion. Researchers from Fudan University in Shanghai, China, led by ecologist Lu Baorong was able to show that a weedy for of a rice crop can acquire a fitness boost from glyphosate resistance. Glyphosate is a powerful herbicide marketed under the trade name Roundup and produced by US biotech giant Monsanto. GM crops with glyphosate resistance allow farmers to use the herbicide to kill most weeds without it damaging their crops.

Glyphosate works by blocking an enzyme known as EPSP synthase, which is involved in the production of essential amino acids in plants. This blocking effect inhibits plant growth, therefore killing weeds. In glyphosate resistant crops, scientists insert added genes into the plant’s genome in order to boost EPSP synthase production. This allows the GM crops to withstand the effects of glyphosate.

In the new study, Lu and his colleagues genetically modified a cultivated rice species to overexpress its own EPSP synthase production. The modified rice were then cross-bred with a weedy relative. The team then allowed the cross-bred plant to breed with one another, creating second generation hybrids that were genetically identical with the exception of the number of copies of the gene encoding EPSP synthase. Crop hybrids that had more copies of the genes responsible for EPSP synthase production, expressed higher levels of the enzyme and produced more of the amino acid tryptophan compared to the unmodified crops.

The researchers found out that the transgenic hybrids of the weedy rice showed higher rates of photosynthesis, grew more shoots and flowers as well as produced from 48 to 125 percent more seeds than their non-transgenic counterparts. The study was conducted without the use of glyphosate, the resistance to which was then intended function for the GM crops.

The study showed that when the transgenes gets into the wild species, the genetic diversity of the plants may be threatened due to the competition. The boost in advantage may give the genetic hybrids outcompete the normal species, possibly wiping them out from their natural habitat. The result of the study indicates that there needs to be a rethinking of the regulation of genetically modified crops. Careful evaluation of the new crops may be required to determine just how safe are they to cultivate, with safety and preservation of biodiversity in the environment taken into consideration.

Source: Nature

 
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