Can the world's favorite fruit, tomato, provide an effective biosynthetic chassis for high-value metabolites?

Abstract

Tomato has a relatively short growth cycle (fruit ready to pick within 65-85 days from planting) and a relatively high yield (the average for globe tomatoes is 3-9 kg fruit per plant rising to as much as 40 kg fruit per plant). Tomatoes also produce large amounts of important primary and secondary metabolites which can serve as intermediates or substrates for producing valuable new compounds. As a model crop, tomato already has a broad range of tools and resources available for biotechnological applications, either increased nutrients for health-promoting biofortified foods or as a production system for high-value compounds. These advantages make tomato an excellent chassis for the production of important metabolites. We summarize recent achievements in metabolic engineering of tomato and suggest new candidate metabolites which could be targets for metabolic engineering. We offer a scheme for how to establish tomato as a chassis for industrial-scale production of high-value metabolites.

Keywords: Chassis; Metabolic engineering; Scale-up production; Specialized metabolites; Tomato.

Fig. 1

Important primary and secondary metabolites and their biosynthetic pathways in tomato fruit. Compounds that have been engineered already in tomato fruit are outlined in purple

Fig. 2

Production of valuable metabolites using the proposed tomato production platform. Using metabolic engineering, valuable compounds can be produced in tomato fruit. The engineered tomato plants could be grown in containment greenhouses. Fruit juice could be processed to produce metabolite extracts and downstream facilities could be used to purify target compounds. (1) Construction of vectors for metabolic engineering in tomato fruit; (2) agrobacterium-mediated transformation of tomato to produce engineered fruit; (3) multiplication of engineered lines for cultivation in containment (insect-proofed) greenhouses; (4) harvesting of fruit; (5) preparation of extracts of high value chemicals from tomatoes. This may be as simple as homogenization and centrifugation to generate ‘tomato water’ for high value, water soluble compounds; (6) chemical separation methods for purification of high value compounds; (7) sale of high value metabolite products from tomato