Janson S, Gisselson L A, Salomon P S, Granéli E
Department of Marine Sciences, University of Kalmar, Sweden.
Parasitol Res. 2000 Nov;86(11):929-33. doi: 10.1007/s004360000272.
Parasitism within the group of dinoflagellates is a widespread phenomenon. Whether the parasitic dinoflagellates exhibit specificity in their infection is not well known, but this possibility has become an important issue in the development of biological control of harmful algal blooms. The 18S rDNA sequences from the parasite Amoebophrya sp. and its dinoflagellate host Dinophysis norvegica were determined and compared with the published sequence of Amoebophrya sp. infecting Gymnodinium sanguineum and other dinoflagellates. The results showed that the sequence from the parasite within D. norvegica was clustered with that of the one from G. sanguineum with 100% bootstrap support in a maximum-likelihood analysis. The observed identity between these two sequences was 93%, which indicates that they are not identical species. The two sequences from Amoebophrya sp. were deeply branched within the group of dinoflagellate sequences and represent the earliest diverging dinoflagellates. The sequence from the parasite Parvilucifera infectans, also infecting D. norvegica, was not closely related to the Amoebophrya sp. sequences. The sequence from D. norvegica appeared as a sister group to a cluster containing Prorocentrum lima and Alexandrium spp. without significant bootstrap support. The data presented herein support the hypothesis that A. ceratii comprises more than one species, and this opens the possibility that infections of harmful algal species might involve more than one Amoebophrya species.
在甲藻群体内寄生是一种普遍现象。寄生性甲藻在感染过程中是否具有特异性尚不清楚，但这种可能性已成为有害藻华生物防治发展中的一个重要问题。测定了寄生性阿米巴藻（Amoebophrya sp.）及其甲藻宿主挪威裸甲藻（Dinophysis norvegica）的18S rDNA序列，并与已发表的感染血红裸甲藻（Gymnodinium sanguineum）和其他甲藻的阿米巴藻序列进行了比较。结果表明，在最大似然分析中，挪威裸甲藻内的寄生藻序列与血红裸甲藻内的寄生藻序列聚类，自展支持率为100%。这两个序列之间的一致性为93%，这表明它们不是同一物种。来自阿米巴藻的两个序列在甲藻序列组内深度分支，代表了最早分化的甲藻。同样感染挪威裸甲藻的寄生性微小夜光藻（Parvilucifera infectans）的序列与阿米巴藻序列没有密切关系。挪威裸甲藻的序列作为包含利马原甲藻（Prorocentrum lima）和亚历山大藻属（Alexandrium spp.）的一个聚类的姐妹群出现，但自展支持率不显著。本文提供的数据支持了“角状阿米巴藻（A. ceratii）包含不止一个物种”这一假说，这使得有害藻种的感染可能涉及不止一种阿米巴藻成为可能。
