Department of Biochemistry Seminar | Dr. Georg Jander

Dr. Georg Jander

Professor, Boyce Thompson Institute for Plant Research 

September 20, 2022 | Whistler 116 | 3:30- 4:30 p.m.

Title: The Perks of Being a Wallflower: Glucosinolates and Cardenolides

 Abstract: The biosynthesis of cardenolides, steroid-derived plant metabolites that are potent inhibitors of essential Na+/K+-ATPases in animal cells, evolved independently in several plant families. Among these, the wallflowers (Erysimum; Brassicaceae) provide an example of relatively recent “escape from herbivory” through the acquisition of cardenolides as a new class of defensive metabolites. Cabbage butterfly larvae and other crucifer-specialist herbivores, which are resistant to the characteristic glucosinolate defenses of the Brassicaceae, cannot tolerate the cardenolides found in wallflowers. We established Erysimum cheiranthoides (wormseed wallflower) as a new genetic model system for investigating the previously unknown cardenolide biosynthesis pathway. After assembling a high-quality E. cheiranthoides genome and developing methods for both transient gene expression and stable transformation, we used genetic mapping, phylogenetic comparisons, and co-expression analysis to discover candidate genes involved in cardenolide biosynthesis. Most of these genes appear to have evolved through duplication and neofunctionalization of previously known genes that encode enzymes for brassinosteroid biosynthesis in plants. In further research, we used CRISPR/Cas9 mutagenesis and metabolite profiling to verify the in vivo functions of the identified genes in cardenolide biosynthesis.