Abstract
This study was carried out to identify the phylogenetic relationship among Phellinus species by comparing the DNA sequences of the 5.8S ribosomal DNA (rDNA) and the internal transcribed spacers (ITSs), ITS1 and ITS2 regions. Two primers from the 3' end of 18S rDNA and the 5' end of 28S rDNA sequences were chosen to amplify the specific ITS regions of Phellinus spp. Phellinus strains used in the study were divided into four clusters by the phylogenetic tree based on the amplified regions of ITS and 5.8S rDNA sequences. The first cluster consist of Phellinus hartigii IMSNU 32041 and Phellinus robustus IMSNU 32068, and the second cluster consists of Phellinus linteus strains and Phellinus weirianus IMSNU 32021. Phellinus laevigatus KCTC 6229, KCTC 6230 and Phellinus igniarius KCTC 6227, KCTC 6228 belong to the third cluster. Finally, Phellinus chrysoloma KCTC 6225 and Phellinus chrysoloma KCTC 6226 are the fourth cluster. In the second cluster the differentiation between Phellinus linteus strains and Phellinus weirianus species were not possible by the comparison of the ITS sequences. These results revealed that Phellinus linteus and Phellinus weirianus cannot be established the concept of species level only by the ITS sequences. Therefore, both physiological and molecular biological methods as well as the sequences of type strains are necessary to classify the strains of these two species accurately. The comparison of the ITS sequences of four Phellinus species indicated that the sequences of the ITS1 generally are more divergent than those of the ITS2. Although the ITS sequences are varied in some species, the conserved regions in both ITS1 and ITS2 are useful tool to differentiate the species. Phellinus linteus and related species have their specific sequences in the ITS1 compared to the other species.
본 실험은 진흙버섯류 7종 15균주에 대한 5.85 rDNA와 ITS 부위의 염기서열을 비교 분석함으로서 종간 및 종내의 유연관계를 조사하였다. 5.8S rDNA와 ITS 부위를 증폭하고자 18S rDNA의 3'말단 부위와 28S rDNA의 5'말단 부위에 두 개의 primer를 이용하여 PCR증폭을 행하였다. 5.8S rDNA와 ITS 부위를 증폭하여 염기서열을 비교 분석한 결과 본 실험에 공시된 Phellinus속의 제균종은 크게 4개의 cluster를 형성하였다. 첫 번째 cluster는 Phellinus hartigii IMSNU 32041, Phellinus robustus IMSNU 32068로 이루어졌고, 두 번째 cluster는 Phellinus linteus KCTC 6190, IMSNU 31014, DGUM 25003, DGUM 25004, Phellinus sp. DGUM 25007, Namsan No. 1과 Phellinus weirianus IMSNU 32021, 세 번째 cluster는 Phellinus laevigatus KCTC 6229, KCTC 6230과 Phellinus igniarius KCTC 6227, KCTC 6228로 이루어졌으며, Phellinus chrysoloma KCTC 6225와 KCTC 6226이 마지막 cluster를 형성하였다. 결과적으로 ITS 염기서열의 결과만으로 볼 때 Phellinus linteus와 Phellinus weirianus는 명확하게 종 단위의 개념을 정립할 수 없었다. 따라서 정확한 분류를 위해 생리학적, 분자생물학적 인 분류방법이 첨가되어야 하며, type strain에 대한 ITS 염기서얼도 결정되어야 한다. Phellinus속의 균들에서는 ITS2부위에 비해 ITS1부위의 변이율이 높았다. ITS 염기서열은 종 구분에 유용한 도구이며, 다른 균종들과 비교해 보았을 때 Phellinus linteus와 Phellinus weirianus에서만 ITS1 부위에서 특이적인 염기서열을 가지고 있었다.