Archipelago architecture and evolution of paclitaxel biosynthesis revealed by the Pseudotaxus chienii haplotype-resolved genome
TL;DR
The authors report genome assembly of Pseudotaxus chienii and show that, while it retains a largely conserved genomic architecture for paclitaxel biosynthesis, extensive degradation of the terminal pathway suggests a substantial loss of paclitaxel-producing capacity.
Abstract
Pseudotaxus chienii, the only species in the genus Pseudotaxus, is closely related to Taxus genus. Whether P. chienii can produce paclitaxel has long remained controversial. Here, we present a chromosome-level, haplotype-resolved genome of P. chienii, with each haplotype ( ~ 15.4 Gb) exhibiting high continuity and completeness. We identify a structurally conserved yet physically dispersed genomic region, termed the Taxane Biosynthetic Archipelago (TBA), containing three biosynthetic gene clusters and collinear core genes essential for taxane biosynthesis. Integrative transcriptomic, metabolite, and heterologous enzymatic analyses reveal that while P. chienii retains a largely conserved genomic architecture associated with paclitaxel biosynthesis, its terminal pathway shows severe functional degradation and may have largely lost the functional capacity for paclitaxel production. Concurrently, it exhibits significant accumulation of taxinine J. This study provides an evolutionary framework for interpreting the long-standing debate on paclitaxel production beyond Taxus, and understanding the evolutionary decay of complex specialized pathways. Paclitaxel biosynthesis beyond Taxus has long been debated. Here, the authors report genome assembly of Pseudotaxus chienii and show that, while it retains a largely conserved genomic architecture for paclitaxel biosynthesis, extensive degradation of the terminal pathway suggests a substantial loss of paclitaxel-producing capacity.