Analysis genome of Pseudotaxus chienii reveals insights into the origin and evolution of taxane biosynthesis

As a sister genus to Taxus, Pseudotaxus holds significant importance for studying the origin and evolution of the taxane biosynthesis pathway. However, the reference genome of Pseudotaxus chienii is yet unavailable. Here, we report a chromosome-level genome assembly of P. chienii (15.6 Gb). We show that P. chienii only possesses a partial taxane pathway, which terminates before taxane 2α-O-benzoyl transferase (TBT), a crucial enzyme responsible for the production of 10-deacetylbaccatin III. With the emergence of the Taxus genus, the limitation posed by the lacking of functional TBT is overcome, allowing for the extension of the existing taxane biosynthesis pathway into a complete Taxol biosynthesis. The protein structure of metal ion catalysis sites in taxadiene synthase (TS) is conserved across the Pseudotaxus and Taxus genera, providing potential sites for enhancing TS activity through enzyme engineering. This comparative genomic analysis contributes to our understanding of the origin and evolution of taxane biosynthesis within the Taxaceae family.