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Herbicide resistance may confer an advantage on plants in the wild.

Credit Xiao Yang
One common genetic-modification method used to make crops more resistant to herbicides was found to be superior over weedy forms of rice. These findings suggest that these modifications can have a broad range of effects beyond the farms and out into the wild.

A variety of crops have been genetically engineered to be resistant to glyphosate. ラウンドアップ This herbicide, initially known as Roundup and then introduced into the market in 1996 under the trade name Roundup. This makes it possible for farmers to eradicate the weeds that grow in their fields without harming their crops.

ラウンドアップ Glyphosate inhibits an enzyme known as EPSP synthase that is responsible for the production of specific amino acids and other molecules. It can also inhibit the growth of plants. ラウンドアップ The method of genetic modification, which is employed for Roundup Ready crops by Monsanto (based in St Louis in Missouri), involves inserting genes in a plant to boost EPSP synthase’s output. The genes typically come from bacteria that have infected plants.

This extra EPSP synthase enables plants to counteract the effects of glyphosate. Biotechnology laboratories are trying to use genes that come from plants instead of bacteria to boost EPSP synthase. This is mainly due to the US law permits regulatory approval that allows organisms that carry transgenes to get accepted.

A few studies have looked into whether transgenes such as those that confer glyphosate resistance are able to — once they are wild or weedy relatives by cross-pollination — make those plants more competitive for survival and reproduction. “The common belief is that any sort of transgene can cause disadvantages in the wild in absence of selection pressure, due to the fact that any additional machinery will lower the fitness,” says Norman Ellstrand, a plant geneticist at the University of California in Riverside.

However, a new study conducted by Lu Baorong, an ecologist from Fudan University in Shanghai, is challenging that notion It reveals that a weedy version of the popular rice plant, Oryza sativa is given a significant fitness boost from the resistance to glyphosate even when glyphosate has not been applied.

Lu and coworkers modified the cultivars of rice to improve its EPSP synthase. The modified rice was crossed with a wild relative.

The researchers then allowed offspring cross-bred to breed with one-another, creating second-generation hybrids that are genetically similar to their parents except the number of duplicates of the gene that codes for EPSP synthase. The hybrids with more copies were more likely to make more tryptophan and have more enzyme levels over their counterparts that were not modified.

Researchers also discovered that the transgenic hybrids had higher rates of photosynthesis, grew more shoots and flowers and produced 48 to 125 percent more seeds per plant than non-transgenic hybridswith or without glyphosate. Lu states that making weedy grains more competitive can increase the difficulties it causes to farmers all over the world whose crops are affected by the pest.

“If the EPSP-synthase genes are introduced into the wild rice plant, their genetic diversity, which is essential to protect may be at risk as the genotype with the transgene would outcompete the normal species,” says Brian Ford-Lloyd an expert in plant genetics at the University of Birmingham, UK. ラウンドアップ “This is one the most obvious instances of extremely plausible negative consequences [of GM crops] upon the environment.”

The research also challenges the notion that crops with genetically modified genes containing additional copies of their genes are safer than crops that have microorganism genes. ラウンドアップ Lu says, “Our study shows this is not always the case.”

According to some scientists this finding suggests that any future regulation for genetically engineered plants should be reconsidered. Ellstrand believes that biosafety laws may be relaxed because we can enjoy a high level security from two decades of genetic engineering. This study isn’t proof that the new products are secure.