A developmental profile of tocol accumulation in oat seeds

Authors: Gutierrezgonzalez, Juan; Wise, Mitchell; Garvin, David

Submitted to: Journal of Cereal Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2012
Publication Date: 12/31/2012
Citation: Gutierrez-Gonzalez, J.J., Wise, M.L., Garvin, D.F. 2012. A developmental profile of tocol accumulation in oat seeds. Journal of Cereal Science. 57(1):79-83.

Interpretive Summary: Oats are an important ingredient in many of our foods. They contain numerous vitamins and minerals, including vitamin E. There is an interest in improving the amount and types of vitamin E in oat grain, but there are no data available on how vitamin E accumulates during the development of oat seed, information which may define the best strategies to accomplish this. In this study we measured patterns of vitamin E accumulation during the course of oat seed development, including both the quantity and types of vitamin E. We also compared the type and amount of vitamin E that accumulates in the whole seed versus within just the embryo of the seed. Results indicate that vitamin E progressively accumulates as the oat seed develops, with the peak amount reached near seed maturity. The relative amounts of the eight types of vitamin E that exist are dramatically different as well, with one increasing in abundance during oat seed development and predominating in mature seed. The relative abundance of vitamin E forms in embryos differs significantly from that found in the whole seed, indicating that the regulation of vitamin E synthesis varies between different parts of the developing seed. By understanding how vitamin E accumulates in oats, new varieties can be tailored to contain particular vitamin E profiles desired both by food producers and for consumers to enhance overall human health status.

Technical Abstract: Oats are a good source of many vitamins and minerals, including compounds that collectively constitute vitamin E, the tocols. Tocols are comprised of two subgroups, tocopherols and tocotrienols. Due to their potent antioxidant properties, attention has been given to the health benefits of tocols in oats. However, despite the interest in oat tocols, little is known about developmental aspects of their accumulation in the grain. Moreover, aside from their role in protecting membranes from oxidative damage, their possible physiological roles in planta have largely gone uninvestigated. In this study we quantified tocol accumulation at five time points during oat seed development and also compared tocol concentration and composition in the whole seed both to endosperm and embryos at a late stage of seed development. The temporal pattern of accumulation of the tocol subgroups was different; while tocopherol concentrations remained relatively constant over the course of seed development, tocotrienol concentrations steadily increased. By the end of seed development, tocotrienols were the most abundant tocol both in whole seed and in seed with embryos removed. In contrast, embryos contained higher concentrations of tocopherols than tocotrienols late in seed development and harbored approximately 25% of the total seed tocols. Differences in both temporal and spatial distribution during seed development suggest distinct roles for tocotrienols and tocopherols. These findings advance our understanding of the regulation of tocol synthesis and accumulation in developing oat seeds.