Effect of GPP synthase and metabolic pathway on sabinene production. A: Effect of GPP synthase. GPPS1, GPP synthase form A. grandis; IspA, GPP synthase from E. coli. B: Effect of metabolic pathway on sabinene production, the pathway details were described in section Figure 1. The strain harboring GPPS2 can produce 2.2-fold higher concentration of sabinene than IspA, while the strain harboring MVA pathway can produce 20-fold higher concentration of sabinene than MEP pathway.