Does the Chemodiversity of Bacterial Exometabolomes Sustain the Chemodiversity of Marine Dissolved Organic Matter?
Does the Chemodiversity of Bacterial Exometabolomes Sustain the Chemodiversity of Marine Dissolved Organic Matter?
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DOI：
10.3389/fmicb.2019.00215
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发表时间：
2019-02
影响因子：
5.2
通讯作者：
Beatriz E. Noriega‐Ortega;G. Wienhausen;A. Mentges;T. Dittmar;M. Simon;J. Niggemann
中科院分区：
文献类型：
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作者：
Beatriz E. Noriega‐Ortega;G. Wienhausen;A. Mentges;T. Dittmar;M. Simon;J. Niggemann
海洋溶解有机物（DOM）是一种复杂的化合物混合物。它的碳含量为 750 Pg C，是地球上最大的碳还原池之一。有人提出，DOM 的多样性是其顽抗性的原因。我们假设海洋 DOM 的化学多样性反映了细菌外代谢组的化学多样性。为了测试这一点，我们培养了两种玫瑰杆菌属模型菌株；使用三种不同的简单有机化合物作为唯一碳源（分别用于抑制 P. inhibens 和 D. shibae 的谷氨酸、葡萄糖、乙酸盐和琥珀酸盐）纯培养中的抑制褐杆菌和柴犬恐龙杆菌。使用傅里叶变换离子回旋共振质谱 (FT-ICR-MS) 和生态多样性测量来表征模型生物的外代谢组。我们在 P. inhibens 和 D. shibae 的外代谢组中检测到了数千个分子质量（分别为 21,105 和 9,386），反映了单一细菌菌株使简单有机化合物多样化的能力。外代谢组的化学组成随着生长阶段的变化而变化，并且根据培养的菌株和所使用的底物的不同而有所不同。我们通过计算创建检测到的外代谢组的组合，模拟了更高多样性的底物、细菌种类和异质生长（不同的生长阶段），以接近自然环境的复杂性。我们比较了这些组合的化学多样性，表明新鲜产生的微生物 DOM 与来自最古老的海洋水团之一（北赤道太平洋中层水）的难熔 DOM 的化学多样性。一些外代谢组的组合显示出比深海难降解DOM更高的丰富度，并且所有组合都显示出更高的功能多样性。在外代谢组和难处理的海洋 DOM 中检测到的 13,509 个分子式中，约 15% 是相同的，即出现在玫瑰杆菌外代谢组和深水样品中。这种重叠进一步支持了我们的假设，即玫瑰杆菌属的海洋细菌有助于海洋 DOM 化学多样性和稳定性的可持续性。
Marine dissolved organic matter (DOM) is a complex mixture of chemical compounds. At 750 Pg C, it is one of the biggest pools of reduced carbon on Earth. It has been proposed that the diversity of DOM is responsible for its recalcitrance. We hypothesize that the chemodiversity of marine DOM is a reflection of the chemodiversity of bacterial exometabolomes. To test this, we incubated two model strains of the Roseobacter group; Phaeobacter inhibens and Dinoroseobacter shibae in pure culture using three different simple organic compounds as sole carbon sources (glutamate, glucose, and acetate and succinate for P. inhibens and D. shibae, respectively). The exometabolome of the model organisms was characterized using Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) and ecological diversity measures. We detected thousands of molecular masses in the exometabolomes of P. inhibens and D. shibae (21,105 and 9,386, respectively), reflecting the capability of single bacterial strains to diversify simple organic compounds. The chemical composition of the exometabolomes changed with growth phase and also differed according to the strain incubated and the utilized substrate. We mimicked a higher diversity of substrates, bacterial species and heterogeneous growth (different growth phases) to approach the complexity of natural environments, by computationally creating combinations of detected exometabolomes. We compared the chemodiversity of these combinations, indicative for chemodiversity of freshly produced microbial DOM to that of refractory DOM from one of the oldest oceanic water masses (North Equatorial Pacific Intermediate Water). Some combinations of exometabolomes showed higher richness than the deep ocean refractory DOM, and all the combinations showed higher functional diversity. About 15% of the 13,509 molecular formulae detected in exometabolomes and refractory oceanic DOM were shared, i.e., occurred in Roseobacter exometabolomes and in deep water samples. This overlap provides further support for our hypothesis that marine bacteria from the Roseobacter group contribute to the sustainability of marine DOM chemodiversity and stability.