# De Novo Hybrid Assembly of the Tripterygium wilfordii Mitochondrial Genome Provides the Chromosomal Mitochondrial DNA Structure and RNA Editing Events

## TL;DR

This study assembles the mitochondrial genome of Tripterygium wilfordii and identifies its structure and RNA editing events, offering insights into its evolution and potential for genetic breeding.

## Contribution

The first de novo hybrid assembly of the T. wilfordii mitochondrial genome, revealing its chromosomal structure and RNA editing sites.

## Key findings

- The T. wilfordii mitogenome is 720,306 bp and encodes 55 genes, including 35 protein-coding genes.
- Phylogenetic analysis shows T. wilfordii is closely related to Euonymus alatus.
- 600 RNA-editing sites were identified, with ccmB and nad4 genes having the highest number.

## Abstract

Tripterygium wilfordii has extremely important pharmaceutical value in both traditional and modern medicine. The mitogenome of T. wilfordii was subjected to assembly and annotation with Nanopore long reads and Illumina short reads in this study. The mitogenome is 720,306 bp in length and is responsible for encoding 55 specific genes, including 35 protein-coding genes (PCGs), 17 transfer RNA (tRNA) genes, and 3 ribosomal RNA (rRNA) genes. Upon repetitive sequence analysis, 223 simple sequence repeats (SSRs), 24 long tandem repeats (LTRs), and 47 dispersed repetitive sequences (DRSs) were identified. The 24 common PCGs were used for phylogenetic analysis, which revealed that T. wilfordii is more closely related to Euonymus alatus. Moreover, mitochondrial plastid DNA (MTPT) analysis revealed eight MTPTs in the mitochondrial genome. Furthermore, 600 RNA-editing sites were detected in the protein-coding genes according to RNA-seq results. Among these genes, the ccmB gene contained the greatest number of sites, followed by the nad4 gene. This is the first study to report the T. wilfordii mitogenome and illustrate its linear structure. The findings of this study will help elucidate the evolution of the T. wilfordii mitogenome and facilitate its potential application in genetic breeding.