Computational study of a bifunctional ent-kaurene synthase from Physcomitrella patens (Hedw.) Bruch & Schimp.: an insight into the origin of terpenoid biosynthesis in plants

Abstract Plants produce many terpenoids including gibberellins and many commercially important secondary metabolites. The final steps of terpenoid production involve terpene synthase (TPS) enzymes. The origin of plant TPS is not known; searches for TPS showed their presence in all plant groups except algae. Although many plants have several genes in their genome that encode TPS enzymes, the bryophyte Physcomitrella patens (Hedw.) Bruch & Schimp. possesses only one bifunctional ent-kaurene synthase (PpCPS/KS), which produces both 16α-hydroxykaurane and ent-kaurene (the precursor of gibberellins). This protein shares characteristics of two unifunctional TPS of higher plants – ent-copalyl diphosphate synthase (CPS) and ent-kaurene synthase (KS). Bifunctional TPS are also found in fungi. In this study, the bifunctional PpCPS/KS has been characterized by some bioinformatics tools. Comparative analysis of PpCPS/KS with some fungal and plant TPS as well as terpenoid-producing bacterial enzymes has been performed. The results indicate that bifunctional TPS came from fungi to bryophytes, probably by horizontal gene transfer and unifunctional TPS gradually evolved from bifunctional TPS in higher plants.