De Novo assembly and phylogenetic analysis of the complete mitochondrial genome of Eleutherococcus senticosus and related araliaceous species.

Eleutherococcus senticosus, a unique herb with significant medicinal and ecological importance, has remained largely unexplored regarding its mitochondrial genome. This research details the complete assembly and annotation of the E. senticosus mitogenome, achieved using a hybrid sequencing strategy that integrates data from Illumina short-read and Nanopore sequencing long-read sequencing data. The mitogenome is 548,869 bp in length and encompasses 78 annotated genes, including 38 essential protein-coding genes (PCGs), 24 transfer RNAs, 13 variable genes, and three ribosomal RNAs. An in-depth investigation of repetitive sequences identified simple sequence repeats, tandem repeats, and dispersed repeats, which are implicated in homologous recombination and genomic variability. Prediction of RNA-editing sites uncovered 587 modifications, primarily involving C-to-U transitions that lead to changes in amino acid sequences within PCGs. Furthermore, the chloroplast genome, measuring 156,802 bp, was examined to uncover structural variations and assess mitochondrial-plastid DNA integration events. Phylogenetic analyses utilizing mitochondrial PCGs elucidated the evolutionary position of E. senticosus within the Araliaceae family, demonstrating a close genetic relationship to Panax species while showcasing unique genomic adaptations. These results provide critical insights into the genetic framework, evolutionary processes, and biological functions of E. senticosus, delivering essential genomic data for further studies on phylogenetics, conservation, and molecular breeding of this valuable medicinal plant.