Assembly and comparative analysis of the initial complete mitochondrial genome of Verbascum thapsus (Scrophulariaceae): a medicinally and ecologically significant species

BACKGROUND: Verbascum thapsus belongs to Scrophulariaceae (a family with ~ 62 genera and ~ 1830 species) and has significant medicinal and ecological value. However, its mitochondrial genome (mtDNA) has not been reported previously. This study aimed to sequence, assemble, and annotate the complete mtDNA of V. thapsus, to clarify its structural characteristics, evolutionary dynamics, and phylogenetic relationships. RESULTS: The assembled V. thapsus mtDNA is a circular molecule of 478,020 bp, with a GC content of 45.02%. It contains 36 protein-coding genes (PCGs), 21 tRNA genes, and 3 rRNA genes. Notable features include abundant repetitive sequences (simple sequence repeats and dispersed repeats), and 468 RNA editing sites (mainly C-to-U conversions). Comparative analysis revealed homologous sequences between mitochondrial and chloroplast genomes, accounting for 3.02% of the mtDNA length. Phylogenetic analysis (based on 14 conserved mitochondrial PCGs) placed V. thapsus within the order Lamiales, supporting its taxonomic position. CONCLUSIONS: This study presents the first complete mtDNA of V. thapsus, which sheds light on mitochondrial genome evolution in Scrophulariaceae. The identified genomic rearrangements, codon usage biases, and RNA editing events form a foundation for future phylogenetic and functional research on V. thapsus and related species.