But in this study, the researchers used a different method, boosting activation of the native epsps gene in rice plants a process called overexpressing to give the plants enough strength to survive an application of herbicide. Because companies that genetically modify commercial crops don't fully disclose their methods, Snow and her colleagues aren't sure how prevalent this method might be, now or in the future.
"This is a relatively new way to get a trait into a crop: taking the plant's own gene and ramping it up," Snow said. "We don't know yet if our findings are going to be generalizable, but if they are, it's definitely going to be important."
To overexpress the native gene in rice, the scientists attached a promoter to it, giving the plant an extra copy of its own gene and ensuring that the gene is activated at all times.
The researchers conducted tests in rice and four strains of a relative of the same species, weedy rice, a noxious plant that infests rice fields around the world. By crossing genetically altered herbicide-resistant rice with weedy rice to mimic what happens naturally in the field, the researchers created crop-weed hybrids that grew larger and produced more offspring than unaltered counterparts even without any herbicide present.
In regulated field experiments, the hybrids containing the overexpressed gene produced 48 percent to 125 percent more seeds per plant than did hybrid plants with no modified genes. They also had higher concentrations of a key amino acid, greater photosynthetic rates and better fledgling seed growth than controls all presumed signs of better fitness in evolutionary terms.
"Fitness is a hard thing to measure, but you can conclude that if a gene gives you a lot more seeds
|Contact: Allison Snow|
Ohio State University