The Holo-Transcriptome of a Calcified Early Branching Metazoan
The Holo-Transcriptome of a Calcified Early Branching Metazoan
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DOI：
10.3389/fmars.2017.00081
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发表时间：
2017-01-01
影响因子：
3.7
通讯作者：
Jackson, Daniel J.
中科院分区：
文献类型：
--
作者：
Germer, Juliane;Cerveau, Nicolas;Jackson, Daniel J.
共生相互作用在动物王国中广泛存在，并且越来越被认为是影响物种进化的重要特征。海绵被广泛认为是后生动物最早的分支林地，通常含有密集、多样但特定的微生物群落，可占其生物量的50%。这些细菌群落实现了影响海绵生理和生态的多种功能，并可能极大地促进了Porifera的进化成功。在这里，我们分析和表征了高钙化海绵Vaceletia sp.的全转录组，并将其与其他海绵转录组和基因组数据进行了比较。Vaceletia sp.拥有丰富多样的微生物群落；通过确定各种脂质途径组分的潜在分子机制，我们表明海绵似乎依赖于其细菌群落提供的短链脂肪酸。与其他海绵的比较表明，这种依赖性可能在微生物群落丰富的海绵中更为明显。此外，细菌聚酮合成酶基因的存在表明，细菌是海绵菌丰富的中链支链脂肪酸的生产者，而海绵菌酸可能是通过短链前体的延伸和去饱和产生的。我们表明，海绵及其微生物群落具有通过不同机制相互作用的分子工具，包括海绵的免疫系统和细菌中真核样蛋白的存在。这些结果扩大了我们对海绵复杂基因库的认识，并显示了海绵及其内源性微生物群落之间代谢相互作用的重要性。
Symbiotic interactions are widespread throughout the animal kingdom and are increasingly recognized as an important trait that can shape the evolution of a species. Sponges are widely understood to be the earliest branching Glade of metazoans and often contain dense, diverse yet specific microbial communities which can constitute up to 50% of their biomass. These bacterial communities fulfill diverse functions influencing the sponge's physiology and ecology, and may have greatly contributed to the evolutionary success of the Porifera. Here we have analyzed and characterized the holo-transcriptome of the hypercalcifying demosponge Vaceletia sp. and compare it to other sponge transcriptomic and genomic data. Vaceletia sp. harbors a diverse and abundant microbial community; by identifying the underlying molecular mechanism of a variety of lipid pathway components we show that the sponge seems to rely on the supply of short chain fatty acids by its bacterial community. Comparisons to other sponges reveal that this dependency may be more pronounced in sponges with an abundant microbial community. Furthermore, the presence of bacterial polyketide synthase genes suggests bacteria are the producers of Vaceletia's abundant mid-chain branched fatty acids, whereas demospongic acids may be produced by the sponge host via elongation and desaturation of short-chain precursors. We show that the sponge and its microbial community have the molecular tools to interact through different mechanisms including the sponge's immune system, and the presence of eukaryotic-like proteins in bacteria. These results expand our knowledge of the complex gene repertoire of sponges and show the importance of metabolic interactions between sponges and their endobiotic microbial communities.