Rutgers scientists have found an efficient way to enhance the nutritional value of corn — the world's largest commodity crop — by inserting a bacterial gene that causes it to produce a key nutrient called methionine, according to a new study.

The Rutgers University-New Brunswick discovery could benefit millions of people in developing countries like South America and Africa who depend on corn as a staple. It could also significantly reduce worldwide animal feed costs.

"We improved the nutritional value of corn, the largest commodity crop grown on Earth," said Thomas Leustek, study co-author and professor in the department of plant biology in the School of Environmental & Biological Sciences. "Most corn is used for animal feed, but it lacks methionine — a key amino acid — and we found an effective way to add it."

The study, led by Jose Planta, a doctoral student at the Waksman Institute of Microbiology, was published online Oct. 9 in Proceedings of the National Academy of Sciences.

Methionine is one of the nine essential amino acids people get from food, according to the National Center for Biotechnology Information. It is needed for growth and tissue repair, improves the tone and flexibility of skin and hair and strengthens nails. The sulfur in methionine protects cells from pollutants, slows cell aging and is essential for absorbing selenium and zinc.

Every year, synthetic methionine worth several-billion dollars is added to animal feed, said study senior author Joachim Messing, a professor who directs the Waksman Institute of Microbiology. The other co-author is Xiaoli Xiang of the Rutgers department of plant biology and Sichuan Academy of Agricultural Sciences in China.

"It is a costly, energy-consuming process," said Messing, whose lab collaborated with Leustek's lab for this study. "Methionine is added because animals won't grow without it. In many developing countries where corn is a staple, methionine is also important for people, especially children. It's vital nutrition, like a vitamin."

The Rutgers scientists inserted an Escherichia coli bacterial gene into the corn plant's genome and grew several generations of corn. The E. coli enzyme 3'-phosphoadenosine-5'-phosphosulfate reductase spurred methionine production in just the plant's leaves instead of the entire plant, Leustek said. As a result, methionine in corn kernels increased by 57%, the report says.

Then, the scientists conducted a chicken feeding trial at Rutgers and showed that the high-methionine corn was nutritious for the birds, Messing said.

"To our surprise, one important outcome was that corn plant growth was not affected," Leustek said.