北部湾涠洲岛红色赤潮藻的分子鉴定

为了弄清北部湾涠洲岛6株疑似红色赤潮藻（Akashiwo sanguinea）株的种类，作者采用光学显微镜和荧光显微镜对其进行形态学初步鉴定；并对藻株SSU rDNA、LSU rDNA和ITS序列测序，利用最大似然法构建系统发育树。结果表明，北部湾涠洲岛6株藻与红色赤潮藻形态特征基本符合；3种序列系统发育树分析均发现北部湾涠洲岛6株藻与不同海域来源的红色赤潮藻聚在同一大分支上，自展值高达99、100、100；与来自亚洲海域的韩国安山株、新加坡株、中国厦门港株序列差异最小，亲缘关系最近，而与其他地理来源的红色赤潮藻序列差异大，亲缘关系较远。红色赤潮藻SSU、LSU、ITS种内遗传距离分别为0.001~0.008、0.003~0.025和0.045~0.406，明显小于该藻与其他裸甲藻科（Gymnodiniaceae）藻属下的种间遗传距离0.032~0.072、0.165~0.222和0.589~1.559，因此可确定北部湾涠洲岛6株藻均为红色赤潮藻。研究结果将为北部湾海域赤潮生物来源与组成、赤潮的发生与管理提供基础信息。

Molecular identification of Akashiwo sanguinea in Weizhou Island, Beibu Gulf

To identify six putative Akashiwo sanguinea strains from the vicinity of Weizhou Island, Beibu Gulf, light microscope and fluorescence microscope observations were used to define morphological characteristics, and the genes SSU rDNA, LSU rDNA, and ITS were sequenced to construct phylogenetic trees using the maximum probability method. The results showed that certain strains morphology was consistent with Akashiwo sanguinea. Besides, all six strains were clustered on the same branch with Akashiwo sanguinea, in the phylogenetic trees based on the SSU rDNA, LSU rDNA, and ITS genes, supported by bootstrap values of 99, 100, and 100, respectively. The minimum genetic distance was between Weizhou Island''s six Akashiwo sanguinea varieties, and Anshan (Korea), Singapore, and Xiamen harbor. The genetic distances of SSU, LSU, and ITS sequences within Akashiwo sanguinea were 0.001-0.008, 0.003-0.025, and 0.045-0.406, respectively, which is significantly smaller than the genetic distances between Akashiwo sanguinea and other Gymnodiniaceae species (0.032-0.072, 0.165-0.222, and 0.589-1.559). As a result, Akashiwo sanguinea six putative strains at Weizhou Island, Beibu Gulf are all Akashiwo sanguineas. This taxonomic and systematic information on causative species in the Weizhou Island and Beibu Gulf region of Guangxi for harmful algal blooms is important in the management of HABs in that region.