Department of Agricultural Biotechnology and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea.
eGnome, Inc, Seoul, Republic of Korea.
PLoS One. 2023 Mar 13;18(3):e0277471. doi: 10.1371/journal.pone.0277471. eCollection 2023.
Unlike other Cirsium in Korea, Cirsium nipponicum (Island thistle) is distributed only on Ulleung Island, a volcanic island off the east coast of the Korean Peninsula, and a unique thistle with none or very small thorns. Although many researchers have questioned the origin and evolution of C. nipponicum, there is not much genomic information to estimate it. We thus assembled the complete chloroplast of C. nipponicum and reconstructed the phylogenetic relationships within the genus Cirsium. The chloroplast genome was 152,586 bp, encoding 133 genes consisting of 8 rRNA genes, 37 tRNA genes, and 88 protein-coding genes. We found 833 polymorphic sites and eight highly variable regions in chloroplast genomes of six Cirsium species by calculating nucleotide diversity, as well as 18 specific variable regions distinguished C. nipponicum from other Cirsium. As a result of phylogenetic analysis, C. nipponicum was closer to C. arvense and C. vulgare than native Cirsium in Korea: C. rhinoceros and C. japonicum. These results indicate that C. nipponicum is likely introduced through the north Eurasian root, not the mainland, and evolved independently in Ulleung Island. This study contributes to further understanding the evolutionary process and the biodiversity conservation of C. nipponicum on Ulleung Island.
与韩国的其他蓟属植物不同，日本蓟（岛蓟）仅分布于朝鲜半岛东海岸的火山岛屿——郁陵岛，是一种没有或很少有刺的独特蓟属植物。尽管许多研究人员对日本蓟的起源和进化提出了质疑，但几乎没有基因组信息可以对其进行估计。因此，我们组装了日本蓟的完整叶绿体，并重建了蓟属内的系统发育关系。叶绿体基因组长 152586bp，编码 133 个基因，包括 8 个 rRNA 基因、37 个 tRNA 基因和 88 个蛋白编码基因。通过计算核苷酸多样性，我们发现了 6 种蓟属植物叶绿体基因组中的 833 个多态性位点和 8 个高度可变区，以及 18 个特定的可变区可以将日本蓟与其他蓟属植物区分开来。系统发育分析结果表明，日本蓟与韩国的本地蓟属植物（猬蓟和日本蓟）比与亚洲蓟属植物（胡枝子蓟和刺苞蓟）更接近。这些结果表明，日本蓟可能是通过北欧亚大陆根而不是大陆传入的，并在郁陵岛独立进化。本研究有助于进一步了解日本蓟在郁陵岛的进化过程和生物多样性保护。
