Abstract: Reynoutria multiflora is a widely used medicinal plant in China. Its medicinal compounds are mainly stilbenes and anthraquinones which possess important pharmacological activities in anti-aging, anti-inflammatory and anti-oxidation, but their biosynthetic pathways are still largely unresolved. Here, we reported a near-complete genome assembly of R. multiflora consisting of 1.39 Gb with a contig N50 of 122.91 Mb and only one gap left. Genome evolution analysis revealed that two recent bursts of LTR contributed significantly to the increased genome size of R. multiflora, and numerous large chromosome rearrangements were observed between R. multiflora and Fagopyrum tataricum genomes. Comparative genomics analysis revealed that a recent whole-genome duplication specific to Polygonaceae led to a significant expansion of gene families associated with diseases tolerance and the biosynthesis of stilbenes and anthraquinones in R. multiflora. Combining transcriptomic and metabolomic analyses, we elucidated the molecular mechanisms underlying the dynamic changes in content of medicinal ingredients in R. multiflora roots across different growth years. Additionally, we identified several putative key genes responsible for anthraquinone and stilbene biosynthesis. We identified a stilbene synthase gene PM0G05131 highly expressed in root, which may exhibit an important role in the accumulation of stilbenes in R. multiflora. These genomic data will expedite the discovery of anthraquinone and stilbenes biosynthesis pathways in medicinal plants.

Key words: comparative genomics, genome assembly, Reynoutria multiflora, stilbene and anthraquinone biosynthesis