Location: Plant, Soil and Nutrition Research2015 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 in-house collaborating maize breeder in FY2014 hindered our progress on maize research in Objective 1 of this project. An outside collaborator has been established to provide maize samples, and also some in-house realignment of resources will be occurring to also help this portion of the research to move forward. Significant findings have been obtained this year demonstrating that certain polyphenols in bean seed coats are potential promoters of Fe uptake, and others are inhibitors of Fe absorption. Defining these mechanisms should contribute to our ability to significantly improve the nutritional quality of iron in beans and other staple food crops. In crops such as beans, our collaboration with ARS scientists at Michigan State University have been extremely productive at identifying bean varieties with enhanced Fe nutritional quality. Our in vitro and in vivo models of Fe bioavailability have clearly demonstrated in this past year that we can predict human results in efficacy studies of Fe-biofortified crops such as beans and pearl millet. This work will be significant for future studies of development and monitoring of Fe-biofortified varieties.
1. Discovery that some polyphenolic compounds inhibit human iron absorption while other polyphenolic compounds can stimulate iron absorption. ARS researchers in Ithaca, New York, have developed new and improved cell culture methods that enable researchers to assess the effects of specific polyphenolic compounds found in staple food crops on the bioavailability of Fe in the human diet. Prior to the development of these cell culture methods that mimic Fe absorption in the human intestine, it was widely considered that all polyphenolic compounds in the diet inhibit iron absorption. Application of these methods has shown that certain specific polyphenolic compounds inhibit iron absorption, and while researchers have discovered that other polyphenolic compounds enhance iron absorption. This accomplishment is significant as this new information will enable nutritionists and plant breeders to more effectively and strategically improve the iron bioavailability of staple food crops.
Hortono, K., Reed, S.M., Ankrah, A., Glahn, R.P., Tako, E.N. 2014. Alterations in gut microflora populations and brush border functionality following intra-amniotic daidzein administration. RSC Advances. 5:6407-6412.
Tako, E.N., Marija, K., Glahn, R.P., Stangoulis, J. 2014. The effect of wheat prebiotics on the gut bacterial population and iron status of iron deficient broiler chickens. Nutrition Journal. 13:58.
Tako, E.N., Hoekenga, O., Kochian, L.V., Glahn, R.P. 2013. High bioavailable iron maize (Zea mays L.) developed through molecular breeding provides more absorbable iron in vitro and in vivo. Nutrition Journal. 12:3.
Tako, E.N., Beebe, S.E., Hart, J.J., Reed, S.M., Glahn, R.P. 2014. Polyphenolic compounds appear to limit the nutritional benefit of biofortified higher iron black bean (phaseolus vulgaris L.). Nutrition Journal. 13:28.
Tako, E.N., Reed, S.M., Budiman, J., Hart, J.J., Glahn, R.P. 2015. Higher iron pearl millet (Pennisetum glaucum L.) provides more absorbable iron that is limited by increased polyphenolic content. Nutrition Journal. 14:11.
Cichy, K.A., Porch, T.G., Beaver, J.S., Cregan, P.B., Fourie, D., Glahn, R.P., Grusak, M.A., Kamfwa, K., Katuuramu, D., McClean, P., Mndolwa, E., Nchimbi-Msolla, S., Pastor Corrales, M.A., Miklas, P.N. 2015. A Phaseolus vulgaris diversity panel for Andean bean improvement. Crop Science. 55:2149-2160.
Dellavalle, D.M., Glahn, R.P. 2014. Differences in relative bioavailability of traditional Bangladeshi meal plans. Food and Nutrition Bulletin. 35(4):431-439.
Liu, X., Glahn, R.P., Arganosa, G.C., Warkentin, T.D. 2014. Iron bioavailability in low phytate pea. Crop Science. 55(1):320-330.
Hart, J.J., Tako, E.N., Kochian, L.V., Glahn, R.P. 2015. Identification of black bean (Phaseolus vulgaris L.) polyphenols that inhibit and promote iron uptake by caco-2 cells. Journal of Agricultural and Food Chemistry. DOI: 10.1021/acs.jafc.5b00531.