Assembly and comparative analysis of the complete mitochondrial genome of Tetrastigma hemsleyanum Diels & Gilg

Tetratigma hemsleyanum Diels & Gilg is a well-known traditional Chinese medicine, renowned for its remarkable medicinal value in various clinical contexts. The corresponding chloroplast and nuclear genomes have since been sequenced, providing valuable information for breeding and exploration. However, the mitochondrial genome of T. hemsleyanum remains uncharacterized, which restricts a broad view of its evolution and utilisation. This work assembled the mitochondrial genome of T. hemsleyanum var. Jinhulu2 combines Illumina and Nanopore sequencing technologies, followed by a comparative analysis with its close relatives. The mitogenome features a multi-chromosomal structure, comprising two circular chromosomes with a total length of 809,173 bp and a GC content of 44.35%. It contains 76 annotated functional genes, including 35 protein-coding genes, 37 tRNA genes, 3 rRNA genes, and 1 pseudogene. Analysis revealed 273 simple sequence repeats, 109 tandem repeats, and 8,733 dispersed repeats, suggesting a higher repeat abundance in T. hemsleyanum relative to related species. RNA editing analysis identified 57 sites within the mitochondrial CDS, all showing a precise cytosine to uracil conversion, typically substituting hydrophilic amino acids with hydrophobic ones. This work presents the first assembled and annotated mitogenome of T. hemsleyanum, enhancing genetic resources for the Tetrastigma genus and paving the way for an in-depth study of this medicinally significant plant.