Evolution-Inspired Engineering of Diterpene Biosynthesis via Chloroplast Genome Modification

Area of Science:

• Plant biotechnology
• Metabolic engineering
• Synthetic biology

Background:

• Terpenes are a diverse class of plant metabolites crucial for plant-environment interactions and industrial uses.
• Nuclear genome engineering for terpene production is established, but chloroplast genome engineering is underdeveloped, primarily in model plants.
• Potato (Solanum tuberosum) is a vital crop, but its potential for engineered terpene production via chloroplasts is unexplored.

Purpose of the Study:

• To establish chloroplast genome engineering for diterpene production in a crop plant, potato.
• To identify a suitable site for transgene integration in the potato chloroplast genome.
• To enhance diterpene production and restore plant growth through metabolic engineering.

Main Methods:

• Identified the trnT/trnL plastomic locus as a novel transgene integration site in potato.
• Inserted a fern-derived bifunctional diterpene synthase gene into the chloroplast genome.
• Co-expressed an algal geranylgeranyl diphosphate synthase gene to boost precursor supply.

Main Results:

• Successfully generated transplastomic potato plants producing novel diterpenes.
• Initial diterpene production led to reduced plant growth.
• Co-expression of the synthase gene restored normal growth and increased diterpene yield.
• Transplastomic plants exhibited comparable agronomic traits to wild-type.

Conclusions:

• Chloroplast genome engineering is a viable strategy for terpene pathway engineering in crops.
• Evolution-inspired engineering in potato enables high-value terpene production.
• This approach holds potential for crop improvement and novel metabolite discovery.