Genetic diversity of small eukaryotes in lakes differing by their trophic status
Genetic diversity of small eukaryotes in lakes differing by their trophic status
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DOI：
10.1128/aem.71.10.5935-5942.2005
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发表时间：
2005-10-01
影响因子：
4.4
通讯作者：
Debroas, D
中科院分区：
文献类型：
--
作者：
Lefranc, M;Thénot, A;Debroas, D
小的真核生物，直径小于5毫米的细胞，是湖泊浮游生物系统的基本组成部分。在这项研究中，通过测序克隆的18S rRNA基因，测定了法国中部山区三个不同营养状况湖泊的小真核生物多样性：贫营养的Godivelle湖、贫营养的Pavin湖和富营养的Aydat湖。结果表明，富营养化湖泊生物类群多样性最低（12个OTUs），寡营养化湖泊生物类群多样性最高（26个OTUs）。某些群体至少出现在两个生态系统中，而其他群体则在采样日期特定于一个湖泊。在这三个文库中鉴定出了隐藻门、金藻门和严格异养的真核生物纤毛门和真菌。在两个湖泊中发现的小真核生物中，在富营养化系统中未发现Choanoflagellida和环境序列（LKM11），而Cercozoa仅限于少营养化和富营养化湖泊。与Perkinsozoa相关的三个otu仅在Aydat文库中被检测到，在那里它们代表了文库克隆的60%。绿藻系和附藻系均为单一无性系，分别存在于Godivelle和Pavin。在研究的127个克隆中，无论文库的来源如何，经典色素生物（自养和混合养）只占很低的比例。本研究表明，小真核生物群落组成可能随营养状态的不同而不同；某些谱系只能在单一的生态系统中发现。
Small eukaryotes, cells with a diameter of less than 5 lim, are fundamental components of lacustrine planktonic systems. In this study, small-eukaryote diversity was determined by sequencing cloned 18S rRNA genes in three libraries from lakes of differing trophic status in the Massif Central, France: the oligotrophic Lake Godivelle, the oligomesotrophic Lake Pavin, and the eutrophic Lake Aydat. This analysis shows that the least diversified library was in the eutrophic lake (12 operational taxonomic units [OTUs]) and the most diversified was in the oligomesotrophic lake (26 OTUs). Certain groups were present in at least two ecosystems, while the others were specific to one lake on the sampling date. Cryptophyta, Chrysophyceae, and the strictly heterotrophic eukaryotes, Ciliophora and fungi, were identified in the three libraries. Among the small eukaryotes found only in two lakes, Choanoflagellida and environmental sequences (LKM11) were not detected in the eutrophic system whereas Cercozoa were confined to the oligomesotrophic and eutrophic lakes. Three OTUs, linked to the Perkinsozoa, were detected only in the Aydat library, where they represented 60% of the clones of the library. Chlorophyta and Haptophyta lineages were represented by a single clone and were present only in Godivelle and Pavin, respectively. Of the 127 clones studied, classical pigmented organisms (autotrophs and mixotrophs) represented only a low proportion regardless of the library's origin. This study shows that the small-eukaryote community composition may differ as a function of trophic status; certain lineages could be detected only in a single ecosystem.