2009年和2010年黄海绿潮浒苔的ITS序列分析

2009年和2010年黄海绿潮爆发时,采集了江苏和山东5个站位的13份漂浮浒苔样品,利用PCR扩增和测序获得了浒苔样品转录间隔区ITS序列(包括5.8S rDNA),依据ITS序列基于邻接法(NJ)和最大简约法(MP)构建系统进化树。形态特征比较表明2009年出现在青岛和乳山的浒苔与2010年出现在青岛、响水和如东的浒苔,形态特征相似。主要特征包括主枝明显,充满气体,分枝较多,藻体细胞纵向排列,形状为四边形或多边形,大小为(13～21)μm×(15～28)μm,一般具有一个蛋白核。比较分析2009年与2010年浒苔的ITS序列全长,发现ITS序列相似性为100%,与GenBank中黄海绿潮浒苔的ITS序列信息完全一致。分子系统学和形态学的结果一致表明2009年和2010年黄海爆发绿潮的浒苔为同一种;结合之前的研究结果,表明2007～2010年连续4 a黄海绿潮的形成种均为浒苔(Ulva prolifera)。

Sequence analysis of ITS regions of Ulva prolifera in green tides in Yellow Sea of China in 2009 and 2010

Thirteen drifting samples were collected at 5 sites in Jiangsu and Shandong in 2009~2010.The internal transcribed spacers(ITS region) including 5.8S rDNA were sequenced.Based on ITS sequences with the neighbor joining(NJ) and maximum parsimony(MP) method,the phylogenetic trees were constructed respectively.The morphological comparison showed that the bloom-forming alga in 2009 was similar to that in 2010,The similar morphological features included the obvious main-branch,which was full of air,algae somatic cell in the longitudinal rows,quadrilateral or polygonal in shape,(13~21) μm ×(15~28)μm in size,and chloroplast with one pyrenoids.Based on the comparative analysis of the full length of ITS sequences from the 13 samples and data from GenBank,it showed that the ITS including 5.8S rDNA sequences of the 13 samples were identical and also the same as the data about Ulva prolifera from the Yellow Sea in the GenBank,which fell into the same clade including the information about U.linza,U.prolifera and U.procera.The molecular and morphological results consistently showed that the bloom-forming alga in the Yellow Sea in 2009 and 2010 was the same species.Combined the results of previous studies,it showd that U.prolifera was the bloom-forming alga in the Yellow Sea for 4 years(2007~2010).