Genetic diversity of Kalopanax pictus populations in Korea based on the nrDNA ITS sequence

Kalopanax pictus is a long-lived deciduous perennial tree in the family Araliaceae mainly distributed in the East Asia. In Korea, this species is of ecological and medical importance. Because typical populations of this species are small and distributed in patches, K. pictus has been considered as a narrow habitat species. To understand the genetic diversity and population structure of this species, the sequence variation of the nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region was analyzed among 18 different K. pictus populations in the present investigation. The nrDNA ITS sequences of Korean populations investigated in this study showed identical of 616 bp in length, and no any nucleotide variation was found in the entire nrDNA ITS region sequence. This result suggested that the K. pictus populations in Korea might belong to the same isolate, and no mutation was found in the nrDNA ITS region. Compared with other known ITS sequence sources from K. pictus populations, only four variable nucleotide sites were found within the entire ITS region. Very narrow genetic diversity appearing in the population level of K. pictus makes us hypothesize that their relatively isolated habitats. The long-lived traits might be one main reason. However, another probability was that the nr- DNA ITS region might be noneffective in classifying populations of K. pictus. Thus, to further understand the phylogenetic relationship of K. pictus populations, more samplings should be performed based on more DNA sequences.