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An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Modified Plants May Need Less Nitrogen
10 May 2004 (All day)
A simple genetic change enables plants to more efficiently take up and use nitrogen, the principal nutrient in fertilizer, researchers now report. Such changes in crop plants could help maintain yields while reducing farmers' dependence on polluting fertilizers.
Farmers in much of the world apply nitrogen-based fertilizer to their land, allowing them to reap richer harvests. All that fertilizer adds roughly 100 million tons of nitrogen to the biosphere--about as much as is produced naturally by all life on Earth. Nitrogen runoff from fields pollutes drinking water in rural areas and creates large dead zones in the world's coastal seas (ScienceNOW, 8 November 2001). To cut the need for fertilizer, researchers have sought to develop crop plants that use nitrogen more efficiently. Genetic engineers had tried to boost enzymes that help plants take up the two most common forms of nitrogen, nitrate and ammonia, and convert them into amino acids and proteins needed for growth. But it didn't make plants any more efficient. Shuichi Yanagisawa of Okayama University in Kurashiki, Japan, and his colleagues took a different tack. Plants assimilate nitrate and ammonia by hanging them on branches of small sugarlike compounds, like ornaments on a Christmas tree. The Japanese researchers added a corn gene called Dof1 that activates several genes that help produce those sugary compounds, thereby giving plants more places to attach nitrogen. The strategy worked. Arabidopsis plants with an incorporated Dof1 gene had higher than ordinary levels of the sugarlike compounds. They had nearly twice the normal level of amino acids, and they incorporated 28% more nitrogen into their tissue. And under low-nitrogen conditions, which caused normal plants to wither and turn yellow, the engineered plants remained green and healthy. The researchers also obtained similar but preliminary results in potato plants, they report online this week in the Proceedings of the National Academy of Sciences. "It's an important breakthrough," says plant molecular biologist Nigel Crawford of the University of California, San Diego. But although excited by the findings, he cautions that researchers will need to check whether the genetic tweaks caused any side effects--such as making the plants tastier to insects--that would make them less useful for crop plants. "You need the big picture," Crawford says.