Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, P.O. Box 94240, 1090 GE Amsterdam, Netherlands.
Department of Marine Ecology, Research Unit Marine Symbioses, GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker Weg 20, 24105 Kiel, Germany.
Environ Microbiol. 2021 Aug;23(8):4489-4504. doi: 10.1111/1462-2920.15642. Epub 2021 Jun 22.
Sponges possess exceptionally diverse associated microbial communities and play a major role in (re)cycling of dissolved organic matter (DOM) in marine ecosystems. Linking sponge-associated community structure with DOM utilization is essential to understand host-microbe interactions in the uptake, processing, and exchange of resources. We coupled, for the first time, DNA-stable isotope probing (DNA-SIP) with 16S rRNA amplicon sequencing in a sponge holobiont to identify which symbiotic bacterial taxa are metabolically active in DOM uptake. Parallel incubation experiments with the sponge Plakortis angulospiculatus were amended with equimolar quantities of unlabelled ( C) and labelled ( C) DOM. Seven bacterial amplicon sequence variants (ASVs), belonging to the phyla PAUC34f, Proteobacteria, Poribacteria, Nitrospirae, and Chloroflexi, were identified as the first active consumers of DOM. Our results support the predictions that PAUC34f, Poribacteria, and Chloroflexi are capable of organic matter degradation through heterotrophic carbon metabolism, while Nitrospirae may have a potential mixotrophic metabolism. We present a new analytical application of DNA-SIP to detect substrate incorporation into a marine holobiont with a complex associated bacterial community and provide new experimental evidence that links the identity of diverse sponge-associated bacteria to the consumption of DOM.
海绵具有非常多样化的相关微生物群落，在海洋生态系统中对溶解有机物质 (DOM) 的（再）循环起着重要作用。将海绵相关群落结构与 DOM 的利用联系起来，对于理解宿主-微生物之间在资源吸收、加工和交换过程中的相互作用至关重要。我们首次将 DNA 稳定同位素探测 (DNA-SIP) 与海绵全共生体的 16S rRNA 扩增子测序相结合，以确定哪些共生细菌类群在 DOM 吸收过程中具有代谢活性。我们用等量的未标记 ( C) 和标记 ( C) DOM 对 Plakortis angulospiculatus 海绵进行平行孵育实验。鉴定出的 7 个细菌扩增子序列变体 (ASV) 属于 PAUC34f、变形菌门、Poribacteria、硝化螺旋菌门和绿弯菌门，它们被认为是 DOM 的首批活性消费者。我们的研究结果支持以下预测：PAUC34f、Poribacteria 和绿弯菌门能够通过异养碳代谢降解有机物，而硝化螺旋菌门可能具有潜在的混合营养代谢。我们提出了一种新的 DNA-SIP 分析应用，用于检测复杂相关细菌群落的海洋全共生体中底物的掺入，并提供了新的实验证据，将不同海绵相关细菌的身份与 DOM 的消耗联系起来。
