Engineered Biosynthesis of Medicinally Important Plant Natural Products in Microorganisms

Plants produce structurally and functionally diverse natural products. Some of these compounds possess promising health-benefiting properties, such as resveratrol (antioxidant) curcumin (anti-inflammatory, anti-allergic and anticancer), paclitaxel (anticancer) and artemisinin (antimalarial). These compounds are produced through particular biosynthetic pathways in the plants. While supply of these medicinally important molecules relies on extraction from the producing species, recent years have seen significant advances in metabolic engineering of microorganisms for the production of plant natural products. Escherichia coli and Saccharomyces cerevisiae are the two most widely used heterologous hosts for expression of enzymes and reconstitution of plant natural product biosynthetic pathways. Total biosynthesis of many plant polyketide natural products such as curcumin and piceatannol in microorganisms has been achieved. While the late biosynthetic steps of more complex molecules such as paclitaxel and artemisinin remain to be understood, reconstitution of their partial biosynthetic pathways and microbial production of key intermediates have been successful. This review covers recent advances in understanding and engineering the biosynthesis of plant polyketides and terpenoids in microbial hosts.