Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, People's Republic of China.
PLoS One. 2013;8(1):e53820. doi: 10.1371/journal.pone.0053820. Epub 2013 Jan 7.
New specimens of the kleptoplastidal dinoflagellate Gymnodinium eucyaneum Hu were collected in China. We investigated the systematics of the dinoflagellate and the origin of its endosymbiont based on light morphology and phylogenetic analyses using multiple DNA sequences. Cells were dorsoventrally flattened with a sharply acute hypocone and a hemispherical epicone. The confusion between G. eucyaneum and G. acidotum Nygaard still needs to be resolved. We found that the hypocone was conspicuously larger than the epicone in most G. eucyaneum cells, which differed from G. acidotum, but there were a few cells whose hypocone and epicone were of nearly the same size. In addition, there was only one site difference in the partial nuclear LSU rDNA sequences of a sample from Japan given the name G. acidotum and G. eucyaneum in the present study, which suggest that G. eucyaneum may be a synonym of G. acidotum. Spectroscopic analyses and phylogenetic analyses based on nucleomorph SSU rDNA sequences and chloroplast 23 s rDNA sequences suggested that the endosymbiont of G. eucyaneum was derived from Chroomonas (Cryptophyta), and that it was most closely related to C. coerulea Skuja. Moreover, the newly reported kleptoplastidal dinoflagellates G. myriopyrenoides and G. eucyaneum in our study were very similar, and the taxonomy of kleptoplastidal dinoflagellates was discussed.
在中国采集到了新的 kleptoplastidal 甲藻 Gymnodinium eucyaneum Hu 标本。我们基于光形态学和使用多个 DNA 序列的系统发育分析，对该甲藻的系统发生及其内共生体的起源进行了研究。细胞呈背腹扁平状，具有尖锐的背腹锥体和半球形腹锥体。G. eucyaneum 和 G. acidotum Nygaard 之间的混淆仍需要解决。我们发现，在大多数 G. eucyaneum 细胞中，背腹锥体明显大于腹锥体，与 G. acidotum 不同，但也有少数细胞的背腹锥体大小几乎相同。此外，本研究中来自日本的一个样本的核 LSU rDNA 部分序列仅有一个位点差异，被命名为 G. acidotum 和 G. eucyaneum，这表明 G. eucyaneum 可能是 G. acidotum 的同义词。基于核形 SSU rDNA 序列和叶绿体 23 s rDNA 序列的光谱分析和系统发育分析表明，G. eucyaneum 的内共生体来源于 Chroomonas（Cryptophyta），与 C. coerulea Skuja 关系最为密切。此外，本研究中新报道的 kleptoplastidal 甲藻 G. myriopyrenoides 和 G. eucyaneum 非常相似，讨论了 kleptoplastidal 甲藻的分类学。
