동중국해에서 분리된 Synechococcus의 16S rDNA와 16S-23S rRNA ITS 방법을 활용한 계통발학적 분석

Abstract

In order to investigate phylogenetic relationships of Synechococcus strinas isolated from the East China Sea, sequences of 16S rRNA gene and 16S-rRNA internal transcribed spacer region(ITS) were determined from 12 Synechococcus isolates. The phylogeny of 12S rRNA gene showed the isolates are divided into 7 distinct clades belonging to marine subcluster 5.1 lineage, including three novel clades not previously recognized. The phylogenetic tree constrcuted from ITS sequences also revealed that our isolates belong to several distinct clusters including novel clades, suggesting the presence of genetically diverse and distinct Synechococcus strains in the East China Sea. In addition, adsorption spectrum of the isolates were analyzed. Most isolates showed absorption peaks at about 495 nm(phycourobilin) and 545 nm (phycoerythrobilin) and low 495 and 545 ratio, which might be general characterstic of coastal strains. However, two green colored strains (Strains KOR 18 and KOR 17) containing low phycoerythrobilin and high phycocyanin contents, and a orange strain (KOR 52) with high 495 to 545 ratio were also isolated. These green colored strins formed a novel clade and the oranged strain clustered within clade III which consists of isolates with high phycourobilin contents. These results suggest that the Synechococcus community in the East China Sea might be genetically as well as physiologically diverse.