Seasonal and Geographical Transitions in Eukaryotic Phytoplankton Community Structure in the Atlantic and Pacific Oceans.
Seasonal and Geographical Transitions in Eukaryotic Phytoplankton Community Structure in the Atlantic and Pacific Oceans.
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DOI：
10.3389/fmicb.2020.542372
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发表时间：
2020
影响因子：
5.2
通讯作者：
Worden AZ
中科院分区：
文献类型：
--
作者：
Choi CJ;Jimenez V;Needham DM;Poirier C;Bachy C;Alexander H;Wilken S;Chavez FP;Sudek S;Giovannoni SJ;Worden AZ
关于真核浮游植物类群因海洋生态系统中营养物质的可获得性而变化的范围有多广，人们已经知道得很多。然而，属和种一级的动态通常是未知的，尽管考虑到适应和驯化过程在这些水平上有所不同，这一点很重要。我们研究了北大西洋(BATS)季节周期和北太平洋东部(ENP)不同营养条件下的浮游植物群落，使用了叶绿体编码的16S rRNA扩增序列变体(ASV)的系统发育分类和其他方法，包括流式细胞仪细胞分类。在BATS营养丰富的深度混合冬季期间，真核浮游植物的扩增以原生植物为主。在层积期间(夏季)，未培养的苔藓植物形成的∼占所有表面质体扩增的35%±10%，并且主要来自草本藻，而硅藻在全年只表现出轻微的短暂贡献。在寡养型ENP中，未培养的苔藓植物也构成了叶绿体扩增的主要部分。近全长16S rRNA序列的系统发育重建建立了11个未培养的苔藓植物环境分支(DEC)。DEC-I和DEC-VI在BATS和ENP的表层苔藓植物中占主导地位，DEC-IV在后者中也起着重要作用。此外，尽管在BATS中不太常见，但弗洛伦西拉相关分支(FC)在ENP中的深度很突出。在这两个生态系统中，表层植物在深层都有显著的贡献，其中PEC-VIII(表层植物环境分支)和(培养的)钙斑单胞菌是最重要的。定量-聚合酶链式反应证实，在相同的寡营养位点表面几乎不存在P.calceolata，在DCM1,500个18SRRNA基因拷贝∼-1的表面。为了进一步确定样本中浮游植物的特征，我们进行了染色和海上单细胞分选实验。测序结果表明，几个未培养的苔藓植物分支由捕食性混合营养体组成。从进化的角度来看，这些细胞在叶绿体基因组中既显示出保守的特征，又显示出独特的特征。在ENP转录本中，我们观察到多个叶绿体基因的高表达，以及psaA基因中的一个自私元件(第二组内含子)的表达。太平洋和大西洋地区的比较分析支持了捕食性苔藓植物在低营养条件下茁壮成长的结论。观察到几个未培养的苔藓植物谱系似乎能够进行光合作用和捕食，这引发了与季节性和长期海洋变化有关的浮游植物营养作用的潜在变化的问题。
Much is known about how broad eukaryotic phytoplankton groups vary according to nutrient availability in marine ecosystems. However, genus- and species-level dynamics are generally unknown, although important given that adaptation and acclimation processes differentiate at these levels. We examined phytoplankton communities across seasonal cycles in the North Atlantic (BATS) and under different trophic conditions in the eastern North Pacific (ENP), using phylogenetic classification of plastid-encoded 16S rRNA amplicon sequence variants (ASVs) and other methodologies, including flow cytometric cell sorting. Prasinophytes dominated eukaryotic phytoplankton amplicons during the nutrient-rich deep-mixing winter period at BATS. During stratification (‘summer’) uncultured dictyochophytes formed ∼35 ± 10% of all surface plastid amplicons and dominated those from stramenopile algae, whereas diatoms showed only minor, ephemeral contributions over the entire year. Uncultured dictyochophytes also comprised a major fraction of plastid amplicons in the oligotrophic ENP. Phylogenetic reconstructions of near-full length 16S rRNA sequences established 11 uncultured Dictyochophyte Environmental Clades (DEC). DEC-I and DEC-VI dominated surface dictyochophytes under stratification at BATS and in the ENP, and DEC-IV was also important in the latter. Additionally, although less common at BATS, Florenciella-related clades (FC) were prominent at depth in the ENP. In both ecosystems, pelagophytes contributed notably at depth, with PEC-VIII (Pelagophyte Environmental Clade) and (cultured) Pelagomonas calceolata being most important. Q-PCR confirmed the near absence of P. calceolata at the surface of the same oligotrophic sites where it reached ∼1,500 18S rRNA gene copies ml–1 at the DCM. To further characterize phytoplankton present in our samples, we performed staining and at-sea single-cell sorting experiments. Sequencing results from these indicated several uncultured dictyochophyte clades are comprised of predatory mixotrophs. From an evolutionary perspective, these cells showed both conserved and unique features in the chloroplast genome. In ENP metatranscriptomes we observed high expression of multiple chloroplast genes as well as expression of a selfish element (group II intron) in the psaA gene. Comparative analyses across the Pacific and Atlantic sites support the conclusion that predatory dictyochophytes thrive under low nutrient conditions. The observations that several uncultured dictyochophyte lineages are seemingly capable of photosynthesis and predation, raises questions about potential shifts in phytoplankton trophic roles associated with seasonality and long-term ocean change.
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影响因子：
10.7
作者：
Castresana, J
通讯作者：
Castresana, J
DOI：
10.1093/bioinformatics/btu638
发表时间：
2015-01-15
期刊：
Bioinformatics (Oxford, England)
影响因子：
--
作者：
Anders S;Pyl PT;Huber W
通讯作者：
Huber W
DOI：
10.1073/pnas.1001665107
发表时间：
2010-08-17
影响因子：
11.1
作者：
Cuvelier, Marie L.;Allen, Andrew E.;Worden, Alexandra Z.
通讯作者：
Worden, Alexandra Z.
DOI：
10.1016/s0967-0645(03)00134-6
发表时间：
2003-01-01
影响因子：
3
作者：
Collins, CA;Pennington, JT;Chavez, FP
通讯作者：
Chavez, FP
影响因子：
1.7
作者：
Bankevich, Anton;Nurk, Sergey;Pevzner, Pavel A.
通讯作者：
Pevzner, Pavel A.