Decoding the Chloroplast Genome of Korean endemic plant Acer okamotoanum: Comparative Genomics, Phylogenetic Insights, and Potential for Marker Development.

Acer okamotoanum, a medicinally significant endemic plant of Korea, has seen limited genomic research. To address this gap, we conducted a comprehensive sequencing and analysis of its chloroplast genome. The assembled genome is 156,242 bp in length, with typical quadripartite structure, consisting of a large single-copy region, a small single-copy region, and two inverted repeat regions. It contains 130 genes, including 85 protein-coding, 37 tRNA, and 8 rRNA genes. Sixteen genes have a single intron, while clpP and ycf3 possess two introns each. Additionally, 17 genes are duplicated within the inverted repeat regions. The genome analysis revealed 92 Simple Sequence Repeats (SSRs), predominantly located in intergenic regions, with a bias toward A/T-rich codons. Comparative analysis with five closely related Acer species highlighted a highly conserved genomic structure, but also revealed differences in SSRs and repeat sequences. Hypervariable regions, such as rpl32-trnL and ycf1, were identified as potential molecular markers for phylogenetic and population studies. Phylogenetic analysis involving 37 chloroplast genomes confirmed the monophyly of the Acer genus and placed A. okamotoanum within the Platanoidea section, closely related to A. truncatum. This study improves the understanding of A. okamotoanum's genomic structure, offering insights for phylogenetic analysis, marker development, and conservation efforts.