Location: Chemistry Research Unit
2012 Annual Report
2. Confirm the identity of previously unknown metabolites through de novo synthesis.
3. Study biosynthetic pathways and biological functions for a subset of novel plant metabolites.
Metabolomics: Identification of inducible bioactive plant metabolites: Novel acidic sesquiterpenoid phytoalexins, termed zealexins, were discovered in Southern Leaf Blight (Cochliobolus heterostrophus) resistant maize lines that were inoculated with this fungus. Additional zealexins were found to strongly accumulate in insect and fungal damaged kernels during development on maturing maize ears. Unknown members of this phytoalexin class were highly enriched in maize lines resistant to aflatoxin accumulation compared to known susceptible lines. Work on structure elucidation and antimicrobial assays began July 30th by grant-funded Research Associate. A time course of maize seedling scutella tissue, harboring high levels of kauralexins and zealexins, was subjected to whole transcriptome shotgun sequencing, termed RNA-seq. This defense enriched transcriptome is currently being screened for cytochrome P450s and other candidate phytoalexin biosynthetic genes which will be biochemically tested for enzyme activity following purification from bacterial and yeast heterologous expression systems.