ARS researchers track down antioxidants in oats

The antioxidant power of oats is derived from avenanthramides (Avns) but their presence in oat grains varies considerably.

Chemist Mitchell Wise from the ARS Cereal Crops Research Unit and fellow chemist Doug Doehlert from the ARS Red River Valley Agricultural Research Center therefore set out to better understand how Avn production is regulated. The ultimate goal of this research effort is increase Avn levels in oat grains so as to increase the antioxidant potential of oats.

To better understand the factors affecting Avn production, the scientists tested 16 oat cultivators and 2 breeding lines at three locations in North Dakota over two years.

Test results​

Wise said the results revealed that Avn production was strongly affected by environment and genotype.

In particular, genotypes with the strongest rust resistance were found to typically have the highest AVN concentrations. But not all cultivators with strong rust resistance produced high concentrations because of environmental factors.

The interplay between environment and genotype is crucial but the scientists said the results do reveal a way forward for oat breeders. According to Wise, they can select certain cultivars for enhanced production of Avns by taking into account crown rust pressure during growth.

Suspension culture system ​

Wise is also further researching the biosynthesis of Avns in the laboratory. He has developed a suspension culture system from oat shoot tissue in which Avns are produced in response to a chemical that mimics fungal infection. Previous studies have found that Avn production increases in oat leaves when the plant is attacked by a fungus.

“The system is a new tool that can be used for more detailed investigation into how certain Avns are produced,”​ said Wise.