Snapshot of a Bacterial Microbiome Shift during the Early Symptoms of a Massive Sponge Die-Off in the Western Mediterranean.
Snapshot of a Bacterial Microbiome Shift during the Early Symptoms of a Massive Sponge Die-Off in the Western Mediterranean.
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DOI：
10.3389/fmicb.2016.00752
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发表时间：
2016
影响因子：
5.2
通讯作者：
Galand PE
中科院分区：
文献类型：
--
作者：
Blanquer A;Uriz MJ;Cebrian E;Galand PE
海洋变暖正在通过涉及海洋无脊椎动物，特别是双壳类动物、珊瑚和海绵的大规模死亡事件影响海洋底栖生态系统。在这些事件中，西地中海地区反复报道了束状鸢尾海绵的大量死亡。我们的研究目的是测试与温度相关的大规模海绵死亡是否与海绵组织中早期不平衡的细菌微生物群有关或之前。我们利用早期发现疾病的优势，比较了健康和早期患病的束状水蛭组织的微生物组。我们的研究结果显示，早期病变组织中的微生物组发生了变化。与健康组织相比，病变组织中γ变形菌群和酸性细菌群的丰度增加，三角洲变形菌群的丰度减少。在操作分类单位（OTU）水平上，群落组成的变化也很明显。与健康组织相比，患病组织含有更多先前在受伤或受压的海绵和珊瑚中发现的细菌序列。病变组织中细菌多样性显著增加，低丰度otu数量较多。我们的研究结果不支持一种特定病原体的假设，无论是弧菌还是任何其他细菌，引发了地中海西北地区束状支原体的大规模死亡。我们的数据表明，通过OTU丰度的变化，健康海绵中细菌微生物群平衡的早期破坏，以及随之而来的海绵适应性和抗感染能力的下降。机会性细菌可以在海绵组织中定植，利用海绵的弱点，在一种或多种致命病原体增殖之前，最终导致海绵大量死亡。
Ocean warming is affecting marine benthic ecosystems through mass mortality events that involve marine invertebrates, in particular bivalves, corals, and sponges. Among these events, extensive die-offs of Ircinia fasciculata sponges have been recurrently reported in western Mediterranean. The goal of our study was to test whether the temperature-related mass sponge die-offs were associated with or preceded by an early unbalanced bacterial microbiome in the sponge tissues. We took advantage of the early detection of disease and compared the microbiomes of healthy vs. early diseased I. fasciculata tissues. Our results showed a microbiome shift in early diseased tissues. The abundance of Gammaproteobacteria and Acidobacteria increased and that of Deltaproteobacteria decreased in diseased vs. healthy tissues. The change in community composition was also noticeable at the operational taxonomic unit (OTU) level. Diseased tissues contained more bacterial sequences previously identified in injured or stressed sponges and corals than healthy tissues. Bacterial diversity increased significantly in diseased tissues, which contained a higher number of low abundance OTUs. Our results do not support the hypothesis of one particular pathogen, whether a Vibrio or any other bacteria, triggering the Northwestern Mediterranean mass mortalities of I. fasciculata. Our data rather suggest an early disruption of the bacterial microbiome balance in healthy sponges through a shift in OTU abundances, and the purported consequent decline of the sponge fitness and resistance to infections. Opportunistic bacteria could colonize the sponge tissues, taking benefit of the sponge weakness, before one or more virulent pathogens might proliferate ending in the mass sponge die-off.