Chromosomal-level genome and multi-omics dataset of Pueraria lobata var. thomsonii provide new insights into legume family and the isoflavone and puerarin biosynthesis pathways.

Abstract

Pueraria lobata var. thomsonii (hereinafter abbreviated as Podalirius thomsonii), a member of the legume family, is one of the important traditional Chinese herbal medicines, and its puerarin extract is widely used in the health and pharmaceutical industry. Here, we assembled a high-quality genome of P. thomsonii using long-read single-molecule sequencing and Hi-C technologies. The genome assembly is ~1.37 Gb in size and consists of 5145 contigs with a contig N50 of 593.70 kb, further clustered into 11 pseudochromosomes. Genome structural annotation resulted in ~869.33 Mb (~62.70% of the genome) repeat regions and 45 270 protein-coding genes. Genome evolution analysis revealed that P. thomsonii is most closely related to soybean and underwent two ancient whole-genome duplication events; one was in the common ancestor shared by legume species and the other occurred independently at around 7.2 million years ago, after its speciation. A total of 2373 gene families were found to be unique in P. thomsonii compared with five other legume species. Genes and metabolites related to puerarin content in tuberous tissues were characterized. A total of 572 genes that were upregulated in the puerarin biosynthesis pathway were identified, and 235 candidate genes were further enriched by omics data. Furthermore, we identified six 8-C-glucosyltransferase (8-C-GT) candidate genes significantly involved in puerarin metabolism. Our study filled a key genomic gap in the legume family, and provided valuable multi-omic resources for the genetic improvement of P. thomsonii.