Carnosic acid biosynthesis elucidated by a synthetic biology platform
Significance Here we report on the development of a modular terpene production platform as a screening tool for the functional characterization of next generation sequencing information and on the application of this system in the characterization of the biosynthetic pathway leading to the potent antioxidant carnosic acid in Lamiaceae. In addition to revealing an important plant natural product biosynthetic pathway, this work highlights the usefulness of synthetic biology approaches in the elucidation of plant natural product biosynthetic pathways and develops yeast as a tool to exploit the wealth of next generation sequencing data that are constantly being produced through transcriptomic, genomic, or metagenomic studies. The approach described here will be useful to numerous researchers studying terpene biosynthesis in plants and microorganisms. Synthetic biology approaches achieving the reconstruction of specific plant natural product biosynthetic pathways in dedicated microbial "chassis" have provided access to important industrial compounds (e.g. artemisinin, resveratrol, vanillin) However, the potential of such production systems to facilitate elucidation of plant biosynthetic pathways has been underexplored. Here we report on the application of a modular terpene production platform in the characterization of the biosynthetic pathway leading to the potent antioxidant carnosic acid and related diterpenes in Salvia pomifera and Rosmarinus officinalis. Four cytochrome P450 enzymes are identified (CYP76AH24, CYP71BE52, CYP76AK6, and CYP76AK8) the combined activities of which account for all of the oxidation events leading to the biosynthesis of the major diterpenes produced in these plants. This approach develops yeast as an efficient tool to harness the biotechnological potential of the numerous sequencing datasets that are increasingly becoming available through transcriptomic or genomic studies.
Proceedings of the National Academy of Sciences