ARS | Publication request: Biosynthesis of avenanthramides in suspension cultures of oat (Avena sativa)

Submitted to: Plant Cell Tissue And Organ Culture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 24, 2008
Publication Date: January 23, 2009
Citation: Wise, M.L., Sreenath, H.K., Skadsen, R.W., Kaeppler, H.F. 2009. Biosynthesis of Avenanthramides in Suspension Cultures of Oat (Avena sativa). Plant Cell Tissue And Organ Culture. 97:81-90.

Interpretive Summary: Avenanthramides are a group of anti-oxidants that are exclusively produced in the oat crop. These phytonutrients have shown anti-atherosclerotic properties as well as protection against oxidative damage in laboratory experiments. In the oat grain the levels of avenanthramides tends to be highly variable with some evidence indicating fungal pathogen pressure as a factor in stimulating avenanthramide production. In these experiments we demonstrate an oat cell suspension culture system that responds to a chemical mimic of pathogen infection by producing avenanthramides. Described are the molecular dynamics of cultured oat cells in response to simulated pathogen attack. The impact of this work is that it provides a system to investigate the factors regulating avenanthramide biosynthesis at the molecular level.

Technical Abstract: Oats produce a novel group of secondary metabolites termed avenanthramides. These compounds are biosynthesized through the action of the enzyme hydroxycinnamoyl CoA: hydroxyanthranilate N-hydroxycinnamoyl transferase (HHT), which catalyzes the condensation of one of several cinnamate CoA thioesters with the amine functionality of anthranilic acid, 4-hydroxy- or 5-hydroxy-anthranilic acid. Although the grain of oat plants usually contain avenanthramides, the levels and composition are highly variable. In oat leaf tissue the biosynthesis of avenanthramides appears to result from elicitation by fungal infection. In this report we demonstrate the biosynthesis of several avenanthramides in what appears as a generalized pathogen response, evidenced by the production of PR-1 protein, in suspension cultures of oat apical meristem callus tissue in response to elicitation with chitin (poly-N-acetyl glucosamine). We demonstrate the dynamics of avenanthramide biosynthesis, HHT activity and HHT mRNA production.