Phylogeny of Korean Hornbeam (Carpinus turczaninovii) based on nuclear ribosomal ITS sequence

The genus Carpinus belonging to Coryloideae, Betulaceae, has significant economic and ornamental importance. This study was undertaken with the aim to understand the genetic diversity among eighteen isolates of Carpinus turczaninovii collected from different geographical regions of Korea, using ribosomal RNA (rRNA) internal transcribed spacer (ITS) sequences, to compare the infraspecific-phylogenetic relationships among C. turczaninovii in Korea, and some known Carpinus plants. The size variation of sequenced rRNA ITS regions was not seen, with 215, 162, 222 bp of ITS1 region, 5.8S rRNA gene, ITS2 region, respectively. However, some certain nucleotide variations resulted in genetic diversity. In the genus Carpinus, C. turczaninovii closely genetic with Castanopsis kawakamii, Carpinus orientalis, Carpinus monbeigiana, and Calyptranthes polynenra formed one monophyletic clade, while Carpinus betulus and Carpinus laxiflora, respectively formed one monophyletic clade. In the present ITS sequence analysis, Carpinus fangiana, Carpinus coreana, Carpinus japonica, and Carpinus caroliniana were considered as Out Group, compared to C. turczaninovii group. The highest intraspecific variation was found between C. caroliniana and C. japonica. The least intraspecific variation was obtained between C. turczaninovii and C. coreana. The results will help further understanding Carpinus infraspecies population and their phylogenetic analysis.