KSPT Workshop (Jeongwoo Seo1P, Yun-Gyeong Choi2, Junhyun Hur3, Hoesu Jeong4, Sein Jeong4, Minkyung Jung1, Se-Eun Jung1, Hyun-Jun Kang2, Iseon Kim5, Woo-Ho Kim6, Yoon-Su Kim2, Dohyeon Kwag3, Ji-Eun Lim6, Hyeonji Moon1, Hwa-Jung Suh2, Jiye Suh1, Tae-Soo Jang4, Sang-Tae Kim3, Sang-Hun Oh2, Seung-Chul Kim5, Young-Dong Kim6, Sangtae Kim1)

1Department of Biology, Sungshin Women's University, Seoul, Korea; 2Department of Biology, Daejeon University, Daejeon, Korea; 3Department of Medical and Biological Sciences, The Catholic University, Bucheon, Korea; 4Department of Biological Science, Chungnam National University, Daejeon, Korea; 5Department of Biological Sciences, Sungkyunkwan University, Suwon, Korea; 6Department of Life Science, Hallym University, Chuncheon, Korea

Plant mitochondrial genomes are characterized by extensive structural variation, frequent rearrangements, and high levels of polymorphism, which often hinder accurate assembly using short-read sequencing alone. Consequently, long-read sequencing approaches are essential for resolving their complex genomic architectures. Here, we report the complete mitochondrial genome of Deutzia paniculata Nakai (Hydrangeaceae), an endangered Korean endemic shrub, assembled using a hybrid sequencing strategy that integrates Oxford Nanopore Technologies (ONT) long reads with Illumina short reads. High-molecular-weight DNA was extracted to ensure the recovery of long mitochondrial fragments, enabling reliable structural reconstruction. Long-read data were assembled using POLAP, an assembler specifically optimized for ONT reads and organellar genome assembly, resulting in a highly reliable mitochondrial genome sequence. The assembled circular mitochondrial genome is 582,750 bp in length with a GC content of 45.4% and contains 64 genes, including 36 protein-coding genes (PCGs), 26 transfer RNA (tRNA) genes, and two ribosomal RNA (rRNA) genes. Eleven genes were identified as cis-spliced, whereas nad2 was confirmed as a trans-spliced gene, reflecting the complex gene organization typical of plant mitochondrial genomes. Phylogenetic analysis based on 17 conserved mitochondrial PCGs revealed that D. paniculata forms a sister relationship with species of Hydrangea, supporting its distinct evolutionary lineage within Hydrangeaceae. Overall, this study highlights the necessity of long-read sequencing for resolving structurally complex plant mitochondrial genomes and provides a valuable genomic resource for future phylogenetic, evolutionary, and conservation studies of East Asian Hydrangeaceae.