Metatranscriptome analyses indicate resource partitioning between diatoms in the field
Metatranscriptome analyses indicate resource partitioning between diatoms in the field
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DOI：
10.1073/pnas.1421993112
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发表时间：
2015-04-28
影响因子：
11.1
通讯作者：
Dyhrman, Sonya T.
中科院分区：
文献类型：
--
作者：
Alexander, Harriet;Jenkins, Bethany D.;Dyhrman, Sonya T.
不同的海洋浮游植物群落承担着全球一半的初级生产。浮游植物的巨大多样性长期以来一直困扰着生态学家，因为这些生物共存于一个各向同性的环境中，同时竞争相同的基本资源(如无机营养物质)。资源的不同生态位划分是解释这种“浮游生物悖论”的一种假说，但很难在原位量化和跟踪浮游植物代谢的变化。在这里，我们使用定量的转录组分析来研究在美国东海岸的河口(纳拉甘西特湾)定期共存的硅藻中氮(N)和磷(P)的代谢途径。已知的N和P代谢途径在硅藻之间的表达不同，表明资源利用能力的明显差异可能会阻止直接竞争。营养改良剂培养扭曲了N/P比率，阐明了营养响应的表达模式，并促进了硅藻之间的定量比较。资源响应(RR)基因集在组成上偏离了生物体的代谢谱，富含与N和P代谢相关的基因。RR基因组的表达随着时间的推移而变化，并且在不同的硅藻之间存在显著差异，导致对相同环境的相反转录反应。代谢能力的明显差异及其在环境中的表现表明，纳拉甘西特湾正在发生硅藻特有的资源分配。这种高分辨率的方法突出了硅藻资源利用的分子基础，以及共生硅藻如何调整它们的细胞生理来划分它们的生态位空间。
Diverse communities of marine phytoplankton carry out half of global primary production. The vast diversity of the phytoplankton has long perplexed ecologists because these organisms coexist in an isotropic environment while competing for the same basic resources (e.g., inorganic nutrients). Differential niche partitioning of resources is one hypothesis to explain this "paradox of the plankton," but it is difficult to quantify and track variation in phytoplankton metabolism in situ. Here, we use quantitative metatranscriptome analyses to examine pathways of nitrogen (N) and phosphorus (P) metabolism in diatoms that cooccur regularly in an estuary on the east coast of the United States (Narragansett Bay). Expression of known N and P metabolic pathways varied between diatoms, indicating apparent differences in resource utilization capacity that may prevent direct competition. Nutrient amendment incubations skewed N/P ratios, elucidating nutrient-responsive patterns of expression and facilitating a quantitative comparison between diatoms. The resource-responsive (RR) gene sets deviated in composition from the metabolic profile of the organism, being enriched in genes associated with N and P metabolism. Expression of the RR gene set varied over time and differed significantly between diatoms, resulting in opposite transcriptional responses to the same environment. Apparent differences in metabolic capacity and the expression of that capacity in the environment suggest that diatom-specific resource partitioning was occurring in Narragansett Bay. This high-resolution approach highlights the molecular underpinnings of diatom resource utilization and how cooccurring diatoms adjust their cellular physiology to partition their niche space.