PlantSynBio: Chassis design for sustainable production of high value terpenoids in the crop species tomato

Plants produce a diverse set of chemicals that are of use to humans as pharmaceuticals, fragrance, food additives, and agrichemicals. One class of compounds are terpenoids which can be used as agrichemicals as they are active against many insects but non-toxic to mammals, biodegradable, and compatible with methods used in sustainable agriculture practices.

However, production of these compounds directly from plants can be challenging due to low yield as well as the time, space, and costs required to grow the plants and extract the compounds. Through advances in biotechnology, it is now possible to engineer production of high value chemicals in plants in a crop species which is simple to grow thereby providing a sustainable approach to production of plant-derived agrichemicals.

In this project, we will use biotechnology approaches to engineer tomato to produce high value terpenoids in fruit and demonstrate that merging chemistry with biotechnology and agriculture provides a platform for sustainable production of chemicals with limited availability from natural sources. We anticipate that access to a sustainable bio-engineered platform for terpenoid production will be of broad use to both the academic and industry sectors.

In this project, we will train personnel in technologies critical to a 21st century workforce. Through annual events and modules at the State Botanic Garden of Georgia, Michigan State University, and University of Minnesota, we will inform the public of the potential of plant systems for sustainable production of chemicals.

Over 50,000 plant terpenoids are known which are synthesized from universal C5 building blocks via the activity of terpene synthases, cytochrome P450s, and glycosyl transferases and function in plant defense, and as attractants to pollinators and symbionts. However, heterologous expression of terpenoid biosynthetic genes in plants is problematic due to the tendency for conversion of the activated products into conjugates or other derivatives via endogenous cytochrome P450s and glycosyl transferases.

Using cutting edge gene editing and transformation technologies, this project will develop new experimental platforms and a paradigm for plant synthetic biology by generating two novel tomato chassis with minimal terpenoid biosynthetic capacity that will enable engineering of high value terpenoid molecules in tomato fruit. Our scientific aims are to (i) Rapidly confirm cytochromes P450 and glycosyl transferases involved in tri- and tetra-terpene biosynthesis in tomato fruit using de novo meristem generated gene-edited lines; (ii) Develop two chassis in tomato that are depleted of tri- and tetraterpenes (carotenoids) in fruit using state-of-the-art gene editing and transformation methods; and (iii) Construct bioengineered tomato lines that synthesize two high value terpenoids as a proof-of-concept.

Within this project we will train scientists in state-of-the-art synthetic biology to facilitate new paradigms in plant synthetic biology. Through annual events and modules with three institutions, we will engage the lay public in the power of plant systems for sustainable chemical production.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.