Chromosome-level genome of Himalayan yew provides insights into the origin and evolution of the paclitaxel biosynthetic pathway

Taxus, commonly known as yew, is a well-known gymnospermwith great ornamental and medicinal value. In this study, by assembling a chromosome-level genome of the Himalayan yew (Taxus wallichiana) with 10.9 Gb in 12 chromosomes, we revealed that tandem duplication acts as the driving force of gene family evolution in the yew genome, resulting in the main genes for paclitaxel biosynthesis, i.e. those encoding the taxadiene synthase, P450s, and transferases, being clustered on the same chromosome. The tandem duplication may also provide genetic resources for the nature to sculpt the core structure of taxoids at different positions and subsequently establish the complex pathway of paclitaxel by neofunctionalization. Furthermore, we confirmed that there are two genes in the cluster encoding isoenzymes of a known enzyme in the paclitaxel biosynthetic pathway. The reference genome of the Himalayan yew will serve as a platform for decoding the complete biosynthetic pathway of paclitaxel and understanding the chemodiversity of taxoids in gymnosperms.

Automated summary

The study reveals that tandem duplication is the driving force of gene family evolution in yew genome, leading to clustering of key genes for paclitaxel biosynthesis on the same chromosome. It also provides genetic resources for nature to shape core structures of taxoids and establish complex pathways of paclitaxel by neofunctionalization.