[Ploidy and whole-genome survey of Corydalis yanhusuo and its related species]

Corydalis Rhizoma, recognized as one of the eight genuine medicinal materials in Zhejiang province, possesses the pharmacological functions of activating blood, regulating Qi movement, and relieving pain. The ploidy of Corydalis yanhusuo, the original plant of Corydalis Rhizoma, is complex, and the whole-genome maps of its closely related species have not yet been obtained, which restricts the research on the genome polyploidization and elite variety breeding of this group. This study employed chromosome preparation and karyotype analysis to reveal the chromosomal karyotypic characteristics of C. yanhusuo, C. turtschaninovii, C. humosa, C. caudata, and C. gamosepala from 20 populations across 8 provinces(municipalities and autonomous regions) in China. Flow cytometry was employed to estimate genome sizes. The results indicated that C. yanhusuo was predominantly tetraploid, with a few wild populations having pentaploidy and hexaploidy, and their genome sizes ranged from 1.24 Gb to 1.94 Gb. C. turtschaninovii was hexaploid, with a genome size of approximately1.57 Gb. C. humosa, C. caudata, and C. gamosepala were diploid, with the genome sizes ranging from 0.56 Gb to 0.69 Gb. Furthermore, whole-genome high-throughput sequencing and two K-mer-based analyses were carried out on two sister species of C. yanhusuo: C. gamosepala and C. turtschaninovii. The results indicated that the genome size of C. gamosepala was(0.57±0.01) Gb, accompanied by a heterozygosity rate of 1.19%±0.15% and a repetitive sequence ratio of 61.19%±0.10%. The genome size of C. turtschaninovii was(1.57±0.07) Gb, along with a heterozygosity rate of 1.76%±0.73% and a repetitive sequence ratio of 91.52%±1.01%. Both of them were highly heterozygous and highly repetitive genomes. This study supplements cytological and genomic data for C. yanhusuo and its related species, laying a foundation for the utilization of C. yanhusuo germplasm resources and the research on polyploidization.