Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/20/2011
Publication Date: 5/13/2011
Citation: Wise, M.L. 2011. Effect of chemical systemic acquired resistance elicitors on avenanthramide biosynthesis in oat (Avena sativa). Journal of Agriculture and Food Chemistry. 59:7028-7038.
Interpretive Summary: Oats produce a group of phenolic antioxidants termed avenanthramides. These metabolites are, among food crops, unique to oats and have shown certain desirable nutritional characteristics such as inhibiting atherosclerotic plaque formation and reducing inflammation. These experiments demonstrate that avenanthramides can be up-regulated in whole plants through the application of benzothiadiazole derivatives (BTH), a commercially available agrochemical used to stimulate plant defense mechanisms against microbial pathogens. This is the first demonstration of avenanthramide biosynthesis being up-regulated in whole plants through an abiotic interaction. The impact is to (1) provide a tool for investigation of mechanisms regulating avenanthramide biosynthesis in whole oat plants, (2) the potential to increase the crown rust resistance in field grown oats and (3) an agronomic tool to increase the levels of avenanthramides in the oat crop.
Technical Abstract: Oats produce a group of phenolic antioxidants termed avenanthramides. These metabolites are, among food crops, unique to oats and have shown some desirable nutritional characteristics, in experimental systems, such as inhibiting atherosclerotic plaque formation and reducing inflammatory responses. Avenanthramides, however, tend to be highly variable in the oat crop and the levels are strongly influenced by environment, genotype and genotype × environment interactions. The experiments reported here demonstrate that avenanthramide levels in vegetative tissue can be enhanced by treatment with agrochemicals formulated to elicit systemic acquired resistance (SAR). Benzothiadiazoles (BTH) and salicylic acid (SA) were both shown to up-regulate avenanthramide biosynthesis within 48 hours in what appears to be a SAR response. The response to BTH was dramatically stronger then SA and was seen to occur for all three of the avenanthramides evaluated (2c, 2f and 2c). SA only resulted in a statistically significant increase in 2c. The response to BTH tends to be fairly long lasting (days to weeks). Avenanthramide 2p is the most strongly up-regulated. In addition to increased avenanthramide levels in leaf tissue, the roots also showed a relatively smaller but distinct increase over time in the treated plants, but not in the untreated plants. The dynamics of the root avenanthramide increase were substantially slower than that observed in the leaves, suggesting these metabolites might be transported from the leaves.