Diterpene Synthase-Catalyzed Biosynthesis of Distinct Clerodane Stereoisomers.

The diterpene synthase clerodienyl diphosphate synthase 1 (PvCPS1) from the crop plant switchgrass (Panicum virgatum) stereoselectively converts (E,E,E)-geranylgeranyl diphosphate (GGPP) into the clerodane natural product, cis-trans-clerodienyl diphosphate (CLPP, 1). Structure-guided point mutations of PvCPS1 redirected product stereoselectivity toward the formation of a rare cis-clerodane diastereomer, cis-cis-CLPP (2). Additionally, an alternative cis-clerodane diastereomer, (5S,8S,9R,10R)-13Z-CLPP (3), was produced when treating PvCPS1 and select variants thereof with the cis-prenyl substrate (Z,Z,Z)-nerylneryl diphosphate (NNPP).

Functional Diversity of Diterpene Synthases in the Biofuel Crop Switchgrass.

Diterpenoids constitute a diverse class of metabolites with critical functions in plant development, defense, and ecological adaptation. Major monocot crops, such as maize () and rice (), deploy diverse blends of specialized diterpenoids as core components of biotic and abiotic stress resilience. Here, we describe the genome-wide identification and functional characterization of stress-related diterpene synthases (diTPSs) in the dedicated bioenergy crop switchgrass ().