The chromosome-level reference genome assembly for Panax notoginseng and insights into ginsenoside biosynthesis

Abstract

<i>Panax notoginseng</i>, a perennial herb of the genus <i>Panax</i> in the family Araliaceae, has played an important role in clinical treatment in China for thousands of years because of its extensive pharmacological effects. Here, we report a high-quality reference genome of <i>P. notoginseng</i>, with a genome size up to 2.66 Gb and a contig N50 of 1.12 Mb, produced with third-generation PacBio sequencing technology. This is the first chromosome-level genome assembly for the genus <i>Panax</i>. Through genome evolution analysis, we explored phylogenetic and whole-genome duplication events and examined their impact on saponin biosynthesis. We performed a detailed transcriptional analysis of <i>P. notoginseng</i> and explored gene-level mechanisms that regulate the formation of characteristic tubercles. Next, we studied the biosynthesis and regulation of saponins at temporal and spatial levels. We combined multi-omics data to identify genes that encode key enzymes in the <i>P. notoginseng</i> terpenoid biosynthetic pathway. Finally, we identified five glycosyltransferase genes whose products catalyzed the formation of different ginsenosides in <i>P. notoginseng</i>. The genetic information obtained in this study provides a resource for further exploration of the growth characteristics, cultivation, breeding, and saponin biosynthesis of <i>P. notoginseng</i>.