Scientists boost the nutritional value of corn

Corn is the world’s largest commodity crop, commonly used as animal feed and forming a staple food in developing countries. Rutgers scientists have found a way to genetically engineer corn to produce a nutrient called methionine in order to enhance its nutritional value.

“Most corn is used for animal feed, but it lacks methionine — a key amino acid — and we found an effective way to add it,” said Thomas Leustek, study co-author and professor in the Department of Plant Biology in the School of Environmental and Biological Sciences.

Published in the Proceedings of the National Academy of Sciences, the study was led by Jose Planta, a doctoral student at the Waksman Institute of Microbiology, with co-author Xiaoli Xiang of the Rutgers Department of Plant Biology and Sichuan Academy of Agricultural Sciences in China, along with senior author Joachim Messing, a professor who directs the Waksman Institute of Microbiology.

The process involved inserting an E. coli bacterial gene which encourages methionine production in the plant’s leaves, rather than the entire plant. This prevented toxic by-products from forming, did not affect plant growth and increased the methionine levels in corn kernels by 57%.

Methionine is one of the nine essential amino acids that humans get from food, and is commonly found in meat. Its health benefits include aiding growth and tissue repair, improving the tone and flexibility of skin and hair, and strengthening nails. The sulfur in methionine protects cells from pollutants, slows cell aging and is essential for absorbing selenium and zinc.

The amino acid is naturally lacking in corn, so synthetic methionine is often added to the crops. However, over a year this could amount to several billion dollars’ worth of synthetic methionine, making it “a costly, energy-consuming process”, according to Messing.

“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.”

Chicken feed is usually prepared as a corn-soybean mixture, and methionine is the essential sulfur-containing amino acid that’s missing. Messing said that after conducting a chicken-feeding trial, the scientists found that the genetically engineered corn was nutritious for them.

Therefore, creating more nutritious corn could reduce animal feed costs, as well benefit millions of people in developing countries who rely on corn as part of their daily diet.

“Our study shows that they wouldn’t have to purchase methionine supplements or expensive foods that have higher methionine,” Messing said.