Location: Plant, Soil and Nutrition Research2014 Annual Report
1. In collaboration with international teams of plant breeders, we will develop lines of staple food crops such as beans, pearl millet, sorghum, rice, lentils and maize with improved Fe and Zn content and bioavailability. 1.A. Identify molecular markers and ultimately the genes that influence iron level and bioavailability in maize seed. Quantitative trait loci (QTL) mapping and an in-vitro digestion/Caco-2 cell culture model system will be used for this research sub-objective. 1.B. Identify molecular markers and ultimately the genes that influence iron level and bioavailability in lentils. Quantitative trait loci (QTL) mapping and an in-vitro digestion/Caco-2 cell culture model system will be used for this research sub-objective. 1.C. Identify agricultural and processing practices that enhance the nutritional quality of Fe in staple food crops. 1.D. Continue our work to identify compounds that promote or inhibit Fe bioavailability in staple food crops. 2. Evaluate a surgical duodenal loop model in poultry as a tool to measure bioavailability of health promoting phytochemicals. 2.A. Determine if absorption of selected phytochemicals can be measured in the poultry duodenal loop model. 2.B. Define bioavailability of specific phytochemicals from select foods using the validated duodenal loop model.
This project has two major objectives. The first is to develop lines of staple food crops with improved bioavailability and content of iron (Fe). To do so we will employ our established screening tools of an iron bioavailability bioassay and an animal model. In conjunction with these tools, we will make use of mass spectroscopy and marker assisted molecular breeding techniques. With these approaches, we will be able to identify and utilize regions of the plant genome that harbor genes associated with the enhanced food crop nutritional quality for Fe. To further complement the above approaches, we will continue our work on the identification of agricultural and food processing practices that enhance the bioavailability and content of Fe and Zn in staple food crops. The second major objective of this project is to develop a method to measure and evaluate the bioavailability of functional phytochemicals from plant foods. To do so, we will assess the use of a surgical model utilizing the unique intestinal anatomy of the broiler chicken to measure absorption of compounds from the duodenal segment of the intestine. This approach uses an established surgical preparation involving anesthetized animals. Our initial efforts with this model will focus on compounds that are common to many staple food crops, fruits and vegetables. These phytochemicals will include the flavonoids epicatechin, quercitin, caffeic acid, chlorogenic acid and kaempferol. Enhancing our knowledge of bioavailability of health promoting phytochemicals will significantly improve efforts to develop more nutritious plant foods.
The loss of our collaborating maize breeder has severely hindered our progress on Objective 1 of this project. We expect to be able to begin moving forward once resources are realigned and a new collaborator is in place. Additional work has been done this year demonstrating that some polyphenols in bean seed coats are potential promoters of Fe uptake, and others are inhibitors of Fe absorption. Publication of results and defining the mechanism(s) as to how these compounds interact with Fe and influence its bioavailability are ongoing. Defining these mechanisms should contribute to our ability to significantly improve the nutritional quality of iron in beans and other staple food crops.