The first mitochondrial genome assembly of Ardisia gigantifolia Stapf: genome characterization, RNA editing, and phylogenetic analysis

Ardisia gigantifolia Stapf, belonging to the genus Ardisia (Primulaceae), is an important traditional medicinal plant with extensive applications in folk medicine. However, its mitochondrial genome remains unexplored. The first mitochondrial genome of A. gigantifolia was sequenced using Illumina NovaSeq 6000 and Oxford Nanopore Technologies platforms and assembled using a hybrid strategy implemented in Unicycler. The genome was assembled into a 639,756 bp circular configuration with a GC content of 42.02%. ONT long reads supported the contig connections within this configuration, although alternative configurations may also exist. The mitochondrial genome contained 38 protein-coding genes, 20 tRNA genes, and 3 rRNA genes. Repetitive sequence analysis identified abundant repeat elements, including 63 simple sequence repeats, 62 tandem repeats, and 73 dispersed repeat regions, which may contribute to mitochondrial genome expansion and structural complexity. In addition, 72 mitochondrial plastid DNA fragments were identified between the mitochondrial and plastid genomes. A total of 451 C-to-U RNA editing sites were predicted across 38 protein-coding genes using Deepred-Mt. Fourteen editing sites in nad4L , including the conversion of its ACG start codon to AUG, and a stop-codon editing site in ccmFC were experimentally validated. Phylogenetic analysis supported a close relationship between A. gigantifolia and Aegiceras corniculatum . This study reports the first mitochondrial genome of A. gigantifolia , providing a valuable genomic resource for understanding mitochondrial genome evolution, phylogenetic relationships, and molecular characteristics of Ardisia .