| HU Zhangxi,DENG Yunyan,LI Yuhang,TANG Ying Zhong. 2018. The morphological and phylogenetic characterization for the dinoflagellate Margalefidinium fulvescens (=Cochlodinium fulvescens) isolated from the Jiaozhou Bay, China. Acta Oceanologica Sinica, 37(10):11－17 |
| The morphological and phylogenetic characterization for the dinoflagellate Margalefidinium fulvescens (=Cochlodinium fulvescens) isolated from the Jiaozhou Bay, China |
| 分离自中国胶州湾的褐色马格里夫藻(Margalefidinium fulvescens)的形态学和系统进化特征 |
| Received:June 27, 2017 |
| DOI：10.1007/s13131-018-1295-0 |
| Key words:Margalefidinium fulvescens morphology phylogeny pumpkin-like structure Jiaozhou Bay China |
| 中文关键词: 褐色马格里夫藻 形态特征 系统进化 南瓜型结构 胶州湾 中国 |
| 基金项目:The National Natural Science Foundation of China under contract No. 41506143; the NSFC-Shandong Joint Fund for Marine Ecology and Environmental Sciences under contract No. U1606404; the National Natural Science Foundation of China under contract Nos 41476142, 61533011 and 41776125; the Scientific and Technological Innovation Project supported by the Qingdao National Laboratory for Marine Science under contract No. 2016ASKJ02; the Creative Team Project of the Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology under contract No. LMEES-CTSP-2018-1. |
| Author Name | Affiliation | E-mail | | HU Zhangxi | CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China
Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China | | | DENG Yunyan | CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China
Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China | | | LI Yuhang | Department of Marine Organism Taxonomy and Phylogeny, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China | | | TANG Ying Zhong | CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
Laboratory for Marine Ecology and Environmental Science, Pilot National Laboratory for Marine Science and Technology(Qingdao), Qingdao 266237, China
Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao 266071, China | yingzhong.tang@qdio.ac.cn |
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| Abstract: |
| The dinoflagellate genus Margalefidinium has been split from Cochlodinium as a new genus recently and Margalefidinium fulvescens is one of the five Margalefidinium species. Margalefidinium fulvescens is toxic and has been reported from the coastal waters of USA, Canada, Mexico, China, Japan, Indonesia, Korea, Pakistan and Spain. Here we provide the morphological and phylogenetic characterization for an isolate of it from the Jiaozhou Bay, Qingdao, China. Our results showed that the vegetative cells were subspherical to ellipsoidal, 34–60 μm in length, and 19–41 μm in width. Both single cell forms and colonies in chains of 2, 4, or 8 cells were observed in cultures, but chain forms with 2 or 4 cells were observed more often in the field samples. The cingulum was rather deep, encircling the cell approximately twice, but the sulcus was rather narrow, surrounding the cell about one turn. The nucleus was spherical and located at the central epicone. The chloroplasts were granular, brownish, and scattered peripherally. An orange pigmented body also appeared in the epicone. The apical groove appeared vase-like as previously described. Under epi-fluorescence microscopy, a pumpkin-like structure was clearly observed, in which cells were embedded. Cells were observed to exit from the structure, which led us to a hypothesis that the structure may provide cells a shelter to avoid predation or to respond to other stresses. The phylogenetic analyses based on partial LSU rDNA sequences indicated that M. fulvescens from the Jiaozhou Bay was grouped with M. fulvescens populations from other origins and closely related to the clade of M. polykrikoides. Our morphological observations and phylogenetic analyses together confirmed the presence of M. fulvescens in China and our monitoring has also observed the species dominant in the dinoflagellate community of the Jiaozhou Bay in the early autumn of 2015, which alerted us to continually monitor this bloom-forming species in the region. |
| 中文摘要: |
| 由于近来对甲藻旋沟藻属（Cochlodinium）的模式种Cochlodinium strangulatum的形态特征和系统进化重新进行了详细研究，特别是基于顶沟的形态、横沟环绕细胞圈数、形成链状群体以及分子特征等对旋沟藻属（Cochlodinium）的分类地位进行了修订，被划分成了两个属：旋沟藻属（Cochlodinium）和马格里夫藻属（Margalefidinium）。褐色马格里夫藻（Margalefidinium fulvescens）是马格里夫藻属这个新属中的一种。褐色马格里夫藻是一种有毒有害的藻华甲藻，该种有较广的地理分布，在美国、加拿大、墨西哥、中国、日本、印度尼西亚、韩国、巴基斯坦和西班牙等国家沿海均有报道。2015年，我们首次在中国胶州湾海域分离到了褐色马格里夫藻并建立了纯培养，详细地观察了该种的形态并对其分子系统学进行了分析。研究结果显示该藻的营养细胞亚球形至椭圆形，长34-60 μm，宽19-41 μm。在实验室纯培养中，可以观察到单细胞及2个、4个或8个细胞组成的细胞链，在野外样品中，常常可以观察到2个或4个细胞组成的细胞链。其横沟较深，环绕细胞大约2圈，纵沟则较窄，环绕细胞约1圈。细胞核圆形，位于上锥的中间。叶绿体颗粒状，呈褐色。上锥可见一橘黄色的色素体。顶沟呈“花瓶型”。在实验室纯培养中，我们观察到了一种“南瓜型”囊状结构，营养细胞可以在这种囊状结构里自由游动，也可以通过伸缩从这种结构中出来。我们推测这种结构可能为该种提供了一种避免被捕食的机制，也可能是对外界其它不利环境的一种响应。基于核糖体大亚基序列（LSU rDNA）的系统学分析显示，分离于中国胶州湾的褐色马格里夫藻与亚洲和美国的多环马格里夫藻（M.polykrikoides）种群的亲缘关系较近。我们的形态学观察和分子进化分析确证了褐色马格里夫藻在我国近海的分布。而且，我们的监测数据显示2015年秋季，该藻已经是胶州湾甲藻群落中的优势种，警示我们需要对该区域的有毒有害藻华种继续进行长期的监测。 |
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