De Novo Assembly and Comparative Analysis of Mitochondrial Genomes of Two Pueraria montana Varieties.

Pueraria montana is a species with important medicinal value and a complex genetic background. In this study, we sequenced and assembled the mitochondrial (mt) genomes of two varieties of P. montana . The mt genome lengths of P. montana var. thomsonii and P. montana var. montana were 457,390 bp and 456,731 bp, respectively. Both P. montana mitogenomes showed a multi-branched structure consisting of two circular molecules, with 56 genes annotated, comprising 33 protein-coding genes, 18 tRNA genes ( trnC-GCA and trnM-CAU are multi-copy genes), and 3 rRNA genes. Then, 207 pairs of long repeats and 96 simple sequence repeats (SSRs) were detected in the mt genomes of P. montana, and 484 potential RNA-editing sites were found across the 33 mitochondrial protein-coding genes of each variety. Additionally, a syntenic sequence analysis showed a high collinearity between the two mt genomes. This work is the first to analyze the mt genomes of P. montana. It can provide information that can be used to analyze the structure of mt genomes of higher plants and provide a foundation for future comparative genomic studies and evolutionary biology research in related species.