The Complete Mitochondrial Genome of the Dioscorea opposita Thunb. cv. Tiegun, a Traditional Medicinal and Edible Crop

This study reports the first complete mitochondrial genome of the traditional medicinal and edible crop, D. opposita (493,268 bp, 45.67% GC). We annotated 39 unique protein-coding genes (PCGs), which included 24 core mitochondrial genes and 15 variable genes, as well as 19 tRNA genes and 3 rRNA genes, along with 245 SSRs and multiple repeat sequences. The longest palindromic repeat measured 260 bp, while the longest forward repeat was 24,068 bp. Furthermore, 723 RNA editing sites were discovered, all involving C-to-U edits, with the nad4 having the highest number of edits (60 sites in total). Comparative genomic and phylogenomic analyses revealed Tiegun yam conserved gene content but structural variations compared to other monocots, underscoring the role of repetitive sequences and recombination in shaping mitochondrial architecture and facilitating cytonuclear co-adaptation. These findings establish a crucial genomic foundation for understanding mitochondrial regulation of growth and metabolic traits in this important species, with implications for future molecular breeding and functional studies of medicinal compound biosynthesis.