Lloyd Sumner Ph.D., sponsored by Brunker Daltonics, will be the keynote speaker for the CIF Winter Symposium.
About the Seminar
Triterpene saponins are important bioactive plant natural products found in many plant families including the Leguminosae, but much of their biosynthetic pathway still remains unknown. We have used a metabolomics approach integrated with gene expression profiling and genome wide associations for the discovery of novel pathway genes/enzymes. This approach exploited genetic and biochemical diversity found within structured M. truncatula germplasm core collections. UHPLC-(-)ESI-QToF-MS was used to profile saponin accumulation across a collection of 300+ M. truncatula ecotypes. The profiling results identified specific ecotypes with significant differential saponin content in the root and/or aerial tissues which were selected, and correlated gene expression profiling was performed. Correlation analyses between gene expression and saponin accumulation revealed high correlations between saponin content with gene expression of β-amyrin synthase, MtCYP716A12, and two cytochromes P450 genes, MtCYP72A67 and MtCYP72A68. Cumulative biochemical and molecular data support that MtCYP72A68 is a multisubstrate, multifunctional oxidase and MtCYP72A67 is a 2β-hydroxylase, both of which function during the early steps of triterpene-oleanate sapogenin biosynthesis. In a similar manner, a novel M. truncatula sugar transferase was also identified and characterized.