[Ploidy and whole genome Survey of Pinellia ternata]

Pinellia ternata, a widely distributed species in China, has been used as a herbal medicine for centuries, with the effects of drying dampness and resolving phlegm. However, its complex ploidy and lack of whole-genome map limit in-depth research on molecular-assisted breeding and multi-omics. In this study, flow cytometry was employed to evaluate the genome sizes of 144 P. ternata plants with different phenotypes collected from 16 geographical locations in China, which revealed the average, maximum, and minimum genome sizes of(7.97±0.43) Gb, 7.06 Gb, and 9.21 Gb, respectively. In addition, the plants from Yunnan province had small genomes(7.24±0.09)Gb, while those with purple skin from Xiantao, Hubei presented similar genome sizes(8.07±0.04)Gb. The plant with a flow cytometry result of 8.18 Gb(2n=8x=104) was identified as an octoploid by the root tip chromosome counting method. Illumina was employed to sequence the octoploid P. ternata at a depth of 75×, and three mainstream methods were used for K-mer analysis. The estimated genome size range of this plant was 7 367.082-7 541.213 Mb, and the heterozygosity rate and repeated sequence ratio were 1.68% and 91.3%±1.7%, respectively. A ploidy Survey of P. ternata populations and a whole-genome survey of specific ploidy strains were carried out, which laid a foundation for whole-genome sequencing and assembly. Meanwhile, this study provided a reference strategy of whole genome Survey for herbal species with complex ploidy, lack of pure lines, and dwarf plants.