Subcellular view of host-microbiome nutrient exchange in sponges: insights into the ecological success of an early metazoan-microbe symbiosis.

摘要: Sponges are increasingly recognised as key ecosystem engineers in many aquatic habitats. They play an important role nutrient cycling due to their unrivalled capacity for processing both dissolved and particulate organic matter (DOM POM) the exceptional metabolic repertoire of diverse abundant microbial communities. Functional studies determining host microbiome uptake exchange, however, limited. Therefore, we coupled pulse-chase isotopic tracer techniques with nanoscale secondary ion mass spectrometry (NanoSIMS) visualise translocation 13C- 15N-labelled food at subcellular level high abundance sponge Plakortis angulospiculatus low Halisarca caerulea. The two species showed significant enrichment DOM- POM-derived 13C 15N into tissue over time. Microbial symbionts were actively involved assimilation DOM, but filtering cells (choanocytes) appeared be primary site DOM POM overall, via pinocytosis phagocytosis, respectively. Translocation carbon nitrogen from choanocytes occurred time, irrespective abundance, reflecting recycling waste products by microbiome. Here, provide empirical evidence indicating that prokaryotic communities a obtain nutritional benefits host-associated lifestyle. interaction between highly efficient filter-feeding its likely provides competitive advantage holobiont oligotrophic environments which they thrive, retaining limiting nutrients. present unique model link symbiotic interactions function, and, cascading effects, functioning, one earliest metazoan–microbe symbioses.