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.

Pueraria lobata var. thomsonii (hereinafter abbreviated as Podalirius thomsonii), a member of legumes, is one of the important traditional Chinese herbal medicines, and its puerarin extraction is widely used in 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 approximately 1.37 Gb in size and consists of 5145 contigs with a contig N50 of 593.70 Kb, further clustered into 11 pseudochromosomes. The genome structural annotation resulted in about 869.33 Mb (about 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, the other occurred independently at around 7.2 million years ago after its specification. A total of 2373 gene families were found unique in P. thomsonii comparing to five other legume species. Genes and metabolites related to puerarin content in tuberous tissues were characterized. A total of 572 genes upregulated in the puerarin biosynthesis pathway were identified, and 235 candidate genes were further enriched by omics data. Furthermore, we identified 6 8-C-glucosyltransferase (8-C-GT) candidate genes significantly involved in puerarin metabolism. Our study filled in a key genomic gap in legume family, and provided valuable multi-omic resources for the genetic improvement of P. thomsonii.

Starch and mineral element accumulation during root tuber expansion period of Pueraria thomsonii Benth.

Pueraria is a medicine plant with rich starch, and thus can be a potential agricultural and industrial resource. In this study, we evaluated the root tuber yield of a cultivar of starch kudzu (Pueraria thomsonii) and the starch accumulation during expansion period of root tuber. Additionally, mineral elements were quantified in root tuber and starch. The results indicated that the starch kudzu cultivar owned high yield of root tuber (greater than42 tons/hm2), high starch content (greater than17% FW) in root tuber, and rich accumulation of beneficial mineral elements. Interestingly, the root tuber of P. thomsonii contained a high concentration of selenium (70 mg/kg FW) and strontium (40 mg/kg FW), and thus it can be utilized as a Se and Sr rich food. Furthermore, Se and Sr can be well preserved in starch through the optimized starch extraction method.