3. **Heterologous Reconstitution of Baccatin III Biosynthesis**: By co-expressing the newly discovered enzymes, TOT1 and T9αH1, with seven other known enzymes involved in paclitaxel biosynthesis, the researchers successfully reconstituted the biosynthesis of **baccatin III** in a heterologous system using *Nicotiana benthamiana* (tobacco). The study demonstrated that only nine core enzymes are required to produce baccatin III, significantly reducing the number of enzymes previously thought necessary for this process (from 13 to 9). 4. **Engineering of Minimal Gene Set**: The researchers reduced the complexity of paclitaxel biosynthesis by defining a minimal gene set for producing baccatin III. This not only simplifies the reconstitution process but also paves the way for future metabolic engineering efforts in heterologous systems like yeast or tobacco. The study showed that these nine enzymes could effectively convert geranylgeranyl pyrophosphate (GGPP) into baccatin III.