| Summary: | <i>Rehmannia chingii</i> is an important medicinal plant with immense value in scientific research. However, its mitochondrial genome (mitogenome) has not yet been characterized. Herein, based on whole-genome Illumina short reads and PacBio HiFi reads, we obtained the complete mitogenome of <i>R. chingii</i> through a de novo assembly strategy. We carried out comparative genomic analyses and found that, in comparison with the plastid genome (plastome) showing a high degree of structural conservation, the <i>R. chingii</i> mitogenome structure is relatively complex, showing an intricate ring structure with 16 connections, owing to five repetitive sequences. The <i>R. chingii</i> mitogenome was 783,161 bp with a GC content of 44.8% and contained 77 genes, comprising 47 protein-coding genes (CDS), 27 tRNA genes, and 3 rRNA genes. We counted 579 RNA editing events in 47 CDS and 12,828 codons in all CDSs of the <i>R. chingii</i> mitogenome. Furthermore, 24 unique sequence transfer fragments were found between the mitogenome and plastome, comprising 8 mitogenome CDS genes and 16 plastome CDS genes, corresponding to 2.39% of the <i>R. chingii</i> mitogenome. Mitogenomes had shorter but more collinear regions, evidenced by a comparison of the organelles of non-parasitic <i>R. chingii</i>, hemiparasitic <i>Pedicularis chinensis</i>, and holoparasitic <i>Aeginetia indica</i> in the Orobanchaceae family. Moreover, from non-parasitic to holoparasitic species, the genome size in the mitogenomes of Orobanchaceae species did not decrease gradually. Instead, the smallest mitogenome was found in the hemiparasitic species <i>P. chinensis,</i> with a size of 225,612 bp. The findings fill the gap in the mitogenome research of the medicinal plant <i>R. chingii</i>, promote the progress of the organelle genome research of the Orobanchaceae family, and provide clues for molecular breeding.
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