Taxonomic revision of Chattonella antiqua, C. marina and C. ovata (Raphidophyceae) based on their morphological characteristics and genetic diversity
Taxonomic revision of Chattonella antiqua, C. marina and C. ovata (Raphidophyceae) based on their morphological characteristics and genetic diversity
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DOI：
10.2216/08-98.1
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发表时间：
2009-11-01
期刊：
影响因子：
1.6
通讯作者：
Kawachi, Masanobu
中科院分区：
文献类型：
--
作者：
Demura, Mikihide;Noel, Mary-Helene;Kawachi, Masanobu
三种石墨藻Chattonella antiqua、C.marina和C.ovata是形成赤潮的有害浮游植物物种，导致养鱼场大规模死亡。这些物种最初仅根据它们的形态特征而相互区分。最近的遗传多样性分析表明，这三个物种极其相似。因此，有必要重新审查这三个物种，以确定它们是否是独立的单一物种。我们从形态特征、核ITS rDNA区域、叶绿体rbcL基因、线粒体COI基因和选定的微卫星区域等方面对这三个物种的104个菌株进行了比较。这三个物种的形态特征形成了一个连续的变异统一体，而不是明确界定的界限。与其他异位附着体比较，它们在所分析的三个区域的遗传差异都在种内水平上，微卫星标记区分了这104个菌株，但这些菌株明显形成了一个地理种群。根据形态特征和系统发育分析，初步识别出3个Chattonella种对应的3个类群。然而，这种三类群的分布不足以证明它们在物种等级上的区别。因此，我们建议对C antiqua和C ovata进行分类修订，将C antiqua和C ovata归入C marina的变种，后者具有名称优先。我们提出了一个新的地位：C marina var。Antiqua(Hada)Demura&Kawachi和C marina var.Ovata(Y.Hara&Chihara)Demura&Kawachi.
Three raphidophyte species, Chattonella antiqua, C. marina and C. ovata, are red tide-forming harmful phytoplankton species, causing mass mortality at fish farms. These species were originally distinguished from each other solely based on their morphological characters. Recent genetic diversity analyses showed that the three species were extremely similar. It was therefore necessary to re-examine these three species to determine if they were independent single species. We compared 104 strains of the three species using morphological characters, nuclear ITS rDNA regions, the chloroplast rbcL gene, the mitochondrion COI gene and selected microsatellite regions. The morphological characters for the three species formed a continuum of variation instead of clearly defined limits. Compared with other selected heterokontophytes, their genetic divergence in the analyzed three regions was found to be at the intraspecies level, Microsatellite markers distinguished each of the 104 strains, but the strains apparently formed a single geographical population. Based on the morphological characters and the phylogenetic analyses, three groups, corresponding to each of the three Chattonella species, were roughly recognized. Nevertheless, this three-group distribution was insufficient to justify their distinction at the species rank. We therefore proposed a taxonomic revision with C antiqua and C ovata reduced to varieties of C marina, this latter having name priority. We proposed a new status: C marina var. antiqua (Hada) Demura & Kawachi and C marina var. ovata (Y. Hara & Chihara) Demura & Kawachi.