Whole grain rolls, corn and brown rice are delicious and contain numerous health benefits. Yet, whole grains are a challenge from their very biology to motivating people to eat more to ensuring an ample worldwide supply.
At the North Carolina Research Campus in Kannapolis, scientists at the NC A&T Center for Excellence in Post Harvest Technologies, the NC State University Plants for Human Health Institute, UNC Charlotte Genomics and Bioinformatics Department and General Mills are tackling the challenges surrounding whole grains by finding ways to increase whole grain consumption, enhance their nutritional value and maximize the potential for grains to prevent and, one day, treat diseases like cancer.
Bigger, More Nutritious Grains
Humans harvest grains primarily for the nutritional value of the endosperm, the placenta-like tissue inside the seeds of most flowering plants that nourish the embryo. Endosperms play a critical role in human nutrition and health. Unraveling the biological complexities surrounding endosperm development can directly impact human health. Tzung-Fu Hsieh, PhD, assistant professor in NC State’s department of Plant Biology at the NC State University Plants for Human Health Institute (PHHI), is leading research in this area that specifically involves the study of DNA methylation.
DNA methylation is a DNA modification that instructs the division and differentiation of cells into specific types of cells and tissues. In grains, biological mechanisms and and molecular signals cause cells to divide and develop into the outer husk called the bran and the inner endosperm and embryo. The endosperm surrounds the embryo serving as its food source. The embryo contains all of the genetic material to sprout into a plant. One of Hsieh’s priorities is to increase the scientific understanding of how outside factors such as environmental stressors can cause inheritable or epigenetic changes to DNA that can determine how an endosperm develops.
Working previously at the University of California Berkeley, Hsieh gained extensive experience with the model plant system Arabidopsis and rice and was on the research team that validated the DEMETER (DME) gene as a regulator of gene imprinting. Gene imprinting is an epigenetic process that involves DNA methylation and leads, in a pair of genes, to one allele (one member of a pair of genes located on a specific chromosome) being active and the other silenced. Whether the active allele is inherited from a maternal or paternal source can affect the size of the endosperm.
At the NCRC, Hsieh is breaking new ground with his research. He’s collaborating with Xu “Sirius” Li, PhD, plant metabolic pathway engineer and PHHI assistant professor, to conduct metabolomic profiles of the seeds he is studying that have larger endosperms.
“We do metabolic profiling to look at what kind of chemical constitutes changes compared to wild type,” Hsieh said. “Hopefully that will allow us to explain why these seeds are bigger. Maybe there are fatty acids or carbohydrate or secondary metabolites that are significantly different. Then it will help us to come to which gene is causing that difference.”
Hsieh foresees that his research will provide new insights into how scientists can impact seed size, nutritional value and other traits valued by farmers and consumers. “We are asking a lot of questions and trying to understand the mechanisms,” he said. “Once we know more, we can find genes and start to design strategies to manipulate them epigenetically to get bigger seeds with certain nutritional value that are beneficial to human health.”
Learn more about Dr. Hsieh’s research, watch the PHHI video.
Did You Know?
♦ The Food and Agriculture Organization of the United Nations estimates that whole grains provide 75 percent of the world’s food supply.
♦ The World Watch Institute reports that humans receive almost half of their calories from grains.
♦ Most Americans consume enough grains, but they are not whole grains. Visit ChooseMyPlate.gov for details on dietary guidelines for whole grains.
♦ Grains are also used for livestock feed, as a source for ethanol and other biofuels as well as for plant-based ingredients in industrial and consumer products.
♦ With the United Nations projecting that the world’s population will climb to nine billion people by 2050, grains are a part of the answer to supplying the world with food, fuel, medicine and other needed commodities.