Unexpected importance of potential parasites in the composition of the freshwater small-eukaryote community
Unexpected importance of potential parasites in the composition of the freshwater small-eukaryote community
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DOI：
10.1128/aem.01156-07
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发表时间：
2008-05-01
影响因子：
4.4
通讯作者：
Debroas, Didier
中科院分区：
文献类型：
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作者：
Lepere, Cecile;Domaizon, Isabelle;Debroas, Didier
利用18S rRNA基因文库构建和荧光原位杂交结合酪胺信号扩增(TSA-FISH)技术，研究了布尔吉特湖中营养湖泊小型真核生物(0.2~5um m)的多样性。在两个日期采集的样本被用来扩展以前对具有一系列营养类型的湖泊使用类似方法获得的数据集。在这个中等营养状态的系统中，记录到了高度的多样性，来自布尔热湖的主要序列与纤毛虫(最大，占可操作分类单位的19%)、隐芽植物(33%)、稻草类(13.2%)和尾丝虫(9%)有关。尽管TSA-FISH结果和克隆文库的比较表明，使用18S rRNA引物的PCR可能低估了绿藻的水平，但异养生物在小真核生物组合中占主导地位。我们发现很大一部分序列属于潜在的淡水浮游植物寄生虫，包括与真菌和Perkinsozoa相关的序列。平均而言，这些序列代表了布尔吉特湖两个日期中每一个获得的OTUS的30%(克隆的40%)。我们的结果提供了关于湖泊小型真核生物多样性和结构的信息，为各种营养类型的湖泊提供了可用的系统发育数据。
The diversity of small eukaryotes (0.2 to 5 mu m) in a mesotrophic lake (Lake Bourget) was investigated using 18S rRNA gene library construction and fluorescent in situ hybridization coupled with tyramide signal amplification (TSA-FISH). Samples collected from the epilimnion on two dates were used to extend a data set previously obtained using similar approaches for lakes with a range of trophic types. A high level of diversity was recorded for this system with intermediate trophic status, and the main sequences from Lake Bourget were affiliated with ciliates (maximum, 19% of the operational taxonomic units [OTUs]), cryptophytes (33%), stramenopiles (13.2%), and cercozoa (9%). Although the comparison of TSA-FISH results and clone libraries suggested that the level of Chlorophyceae may have been underestimated using PCR with 18S rRNA primers, heterotrophic organisms dominated the small-eukaryote assemblage. We found that a large fraction of the sequences belonged to potential parasites of freshwater phytoplankton, including sequences affiliated with fungi and Perkinsozoa. On average, these sequences represented 30% of the OTUs (40% of the clones) obtained for each of two dates for Lake Bourget. Our results provide information on lacustrine small-eukaryote diversity and structure, adding to the phylogenetic data available for lakes with various trophic types.