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In the wild, herbicide resistance might confer an advantage to plants.

ラウンドアップ Weedy rice may absorb transgenes derived from genetically modified rice through cross-pollination. Credit: Xiao Yang
The use of genetic modification to make crops resistant to herbicides is widely used to produce advantages for the varieties of rice that are weedy. ラウンドアップ 原液 筆 The findings suggest that this modification may be able to positively impact wild rice varieties and crops.

A range of crop varieties have been modified genetically so that they become immune to Roundup herbicide glyphosate. This resistance to glyphosate enables farmers to get rid of herbicides, without causing damage to their crop.

Glyphosate hinders growth of plants through blocking an enzyme, known as EPSP synthase. This enzyme is involved in the creation of certain amino acids and other molecules that make up as much as 35% of the plant's mass. Genetic modification, like the Roundup Ready crops manufactured by Monsanto in St. Louis, Missouri, involves inserting genes to a crop's genetic code in order to increase EPSP production. These genes usually come from bacteria that has caused the infection of the plants.

This additional EPSP synthase permits the plant to withstand the effects from glyphosate. Biotechnology labs have also attempted to use plants' genes to increase EPSP-synthase, partly to make use of an American loophole that permits regulatory approval of transgenes not derived bacterial pests.

Few studies have looked into whether transgeneslike those that confer resistance the chemical glyphosate can make plants more resilient to surviving and reproduce once they cross-pollinate with wild or weedy species. Norman Ellstrand is a University of California Riverside plant geneticist. "The assumption is that any kind of transgene can cause disadvantage in the wild, in the absence of selective pressure due to the fact that it reduces the fitness of the plant," Ellstrand said.

Lu Baorong from Fudan University in Shanghai is in the process of challenging this notion. The study demonstrates that glyphosate resistance , even when applied to a weedy variety of the rice crop can provide a significant health boost.

ラウンドアップ In their study, which was published this month in New Phytologist 1, Lu and his colleagues genetically modified the cultivated rice species to increase the expression of its own EPSP synthase. They crossed the altered rice with a weedy ancestor.

The team then allowed offspring that were cross-bred to breed with one another, resulting in second generation hybrids which were genetically identical to their parents with the exception for the number of copies of the gene that encodes EPSP synthase. Likely, the ones with more copies expressed greater levels of the enzyme, and produced more amino acids tryptophan than the unmodified ones.

Researchers also discovered that transgenic hybrids produced 48 to 125 percent more seeds per plant, had greater rates of photosynthesis and more shoots than non-transgenic ones.

Lu suggests that making rice that is weedy more competitive could increase the risk for farmers across the world who's fields are being infested by the pest.

Brian Ford Lloyd, a UK plant scientist, said that the EPSP Synthase gene may be introduced in wild rice varieties. ラウンドアップ 朝露 This could threaten their genetic diversity, which is extremely vital. "This is one of the clearest instances of the extremely damaging impacts [of GM crops] on the environment."

The public belief that genetically-modified crops containing additional copies of their genes are safe is challenged by this study. ラウンドアップ Lu says that "our study is not proving this to be the case."

Researchers say these findings should prompt an overhaul of how genetically modified plants will be regulated in the future. Ellstrand believes that biosafety laws may be relaxed because we can benefit from a high degree of comfort from two decades worth of genetic engineering. "But the study still indicates that innovative products require careful evaluation."