Structure and multipartite genome architecture of the mitochondrial genome in the endangered medicinal plant Fritillaria taipaiensis P. Y. Li

Fritillaria taipaiensis: a medicinal plant of the Liliaceae family endemic to the Qinling Mountains and southern regions of China, is renowned for its therapeutic properties in relieving cough and moistening the lungs. Despite growing interest in the organellar genomes of related species, the mitochondrial genome (mitogenome) of F. taipaiensis has remained uncharacterized. In this study, we successfully assembled and annotated the complete mitogenome of F. taipaiensis using a combination of Illumina and Nanopore technologies. The mitogenome consisted of 23 circular chromosomes with a total length of 847,160 bp and contained 49 annotated genes, including 34 protein-coding genes (PCGs), 12 transfer RNA (tRNA) genes, and 3 ribosomal RNA (rRNA) genes. Codon usage analysis revealed a strong bias toward A- and U-ending codons. Additionally, we identified 178 simple sequence repeats (SSRs) and 127 dispersed repeats. We also detected ten chloroplast-derived DNA fragments transferred to the mitogenome, most of which involved tRNA genes. A total of 488 RNA editing events were predicted in PCGs, all involving C-to-U conversions. Phylogenetic analysis based on 21 representative plant mitogenomes placed F. taipaiensis in a position congruent with its traditional taxonomic classification. These findings enhance our understanding of the mitogenome architecture and evolutionary dynamics of F. taipaiensis and provide valuable genomic resources for future studies in conservation biology, population genetics, and comparative genomics within the Fritillaria genus.