我国近海浒苔漂浮种类ITS与18SrDNA序列相似性分析

Analysis of the similarity on ITS and 18S rDNA sequence of the main species from free-floating Enteromorpha along Chinese coast

2008年6-7月在青岛近海海域再次发生大量浒苔漂浮现象,并且江苏连云港、如东近海海域也发生了浒苔漂浮现象。实验分别对青岛、连云港、如东海域采集样本进行了nrDNA的ITS全长序列和18S rDNA序列分析及相似性比对。结果表明,青岛、连云港、如东海域主要漂浮种类QD-01(青岛)、QD-02(青岛)、QD-03(青岛)、LY-01(连云港)、RD-02(如东)5个样品的ITS全长序列相似性为100%,表明青岛、连云港、如东三地沿海浒苔漂浮主要种类为同一种浒苔。18S rDNA序列分析结果也支持这个判断。根据相似性比对和BLAST分析结果,如东海域浒苔漂浮种类还发现少量另外2种绿藻(RD-01和RD-03),其中RD-01为浒苔属。浒苔主要漂浮种类与目前采集到的三地定生浒苔样本ITS全长序列比对存在一定差异,歧化度小于0.3%。

In June and July, 2008, a large number of free-floating Enteromorpha were found in Qingdao coast, and it also happened in Lianyungang coast and Rudong coast, Jiangsu Province. The Enteromorpha samples were collected from Qingdao, Lianyungang and Rudong coasts, and their ITS and 18S rDNA genes were cloned and sequenced. Based on the sequence data of ITS and 18S rDNA, the molecular phylogenetic analysis was carried out. The result of the ITS sequence analysis showed that the similarity of ITS sequence between 5 samples （ QD-01, QD-02, QD-03, LY-01, RD-02） was 100%. It indicated that main free-floating Enteromorpha species from Qingdao coast, Lianyungang coast and Rudong coast were the same species. The result was also supported by 18S rDNA sequence analysis. According to sequence similarity and BLAST analysis, there were another 2 species in free-floating Enteromorpha in Rudong. RD-01 belonged to Enteromorpha. The results of pairwise sequence divergency analysis showed that there was no difference between the main free-floating species from Qingdao, Lianyungang and Rudong coasts, and the values were very low （0.3%） between the free-floating Enteromorpha species and attached Enteromorpha species from Qingdao, Lianyungang and Rudong coasts.