Comprehensive analysis of the complete mitochondrial genome of Distylium chinense

Distylium chinense is a flood-tolerant woody species distributed in the hydro-fluctuation zone of the Three Gorges Reservoir in the Yangtze River basin and plays an important role in regional ecological restoration. Nevertheless, its mitochondrial genome (mitogenome) has not yet been characterized.

Here, the complete mitogenome of D. chinense was de novo assembled using a hybrid sequencing strategy integrating MGISEQ-2000 and Nanopore platforms. Codon usage bias was evaluated based on relative synonymous codon usage (RSCU). Simple sequence repeats (SSRs), mitochondrial plastid DNA (MTPTs) fragments, and RNA editing sites were also identified.

The assembled mitogenome was 916,504 bp in length, with a GC content of 46.17%, and contains 39 unique protein-coding genes (PCGs), 19 transfer RNA (tRNA) genes, and 3 ribosomal RNA (rRNA) genes. A total of 294 SSRs, 17 MTPTs fragments, and 676 RNA editing sites were detected in the mitogenome. Phylogenetic analysis placed D. chinense within the order Saxifragales, showing the closest relationship to Distylium racemosum.

Collectively, these results provide a comprehensive characterization of the D. chinense mitogenome and establish a valuable genomic resource for future studies on mitochondrial genome evolution and the molecular basis of flood tolerance.