Chromosome-scale genome assembly and annotation of Huzhang (Reynoutria japonica).

Reynoutria japonica, commonly known as Huzhang or Japanese knotweed, is a perennial herbaceous plant belonging to the family Polygonaceae and order Caryophyllales. This plant is valued for its traditional medicinal uses in China. In this study, we present a high-quality, chromosome-scale reference assembly for R. japonica using a combination of PacBio long-read sequencing, Hi-C reads, and Illumina short-read sequencing. The final assembled genome spans approximately 3.30 Gb, with a contig N50 of 1.39 Mb. Notably, 99.22% of the assembled sequences were anchored to 22 pseudo-chromosomes, and 74.79% of the genome is composed of repetitive elements. Genome annotation revealed 68,646 protein-coding genes and 14,788 non-coding RNAs. This genomic resource provides a robust foundation for comparative genomics and will enable deep insights into the evolutionary relationships across related species.