Unidentified enzymes responsible for acetoxylation of sesquiterpene lactones

Identify the plant enzymes that catalyze acetoxylation of sesquiterpene lactones, including those forming acetoxylated germacranolides and heliangolides such as pyrethrosin in Tanacetum cinerariifolium and related compounds in Viguiera laciniata and Dicoma species.

Background

Several acetoxylated sesquiterpene lactones with notable biological activities are reported, for example pyrethrosin in Tanacetum cinerariifolium and acetoxylated heliangolides in Viguiera laciniata. While acetyltransferases are implicated generally, the precise enzymes and their substrate specificities are not yet defined.

Resolving the enzymes responsible for acetoxylation would illuminate late-stage STL tailoring and support rational biosynthetic modification to tune bioactivity.