Transcriptomic data of two Mediterranean sponges exposed to bacterioplankton and symbiont consortia. Sponge transcriptomic response to bacterioplankton vs. symbiotic microbes

Sponges (phylum Porifera) are basal filter feeders constantly interacting with microbial communities from the water column and with the symbiotic partners they harbor. How sponges discriminate between different microbial consortia is still not fully understood. There is initial evidence that immune receptors are involved in the sponge-microbe crosstalk, but experimental data is still scarce. We implemented incubation experiments followed by RNA-Seq differential gene expression analysis to characterize the molecular response of two Mediterranean sponge species upon exposure to bacterioplankton and symbiont. Individuals of the sponges Aplysina aerophoba and Dysidea avara were incubated with microbial consortia enriched from ambient seawater or with the symbiont community extracted from A. aerophoba, and sampled after 1 h, 3 h, and 5 h for RNA-Seq. The response of D. avara involved higher number of differentially expressed genes than A. aerophoba, and involved high expression of genes related to immunity, ubiquitination and signaling. We inferred that D. avara sensed the bacteria consortia by different NLRs, but in both cases, the downstream signaling seems to involve inflammatory pathways. Contrary, A. aerophoba slightly responded to symbiont encountered by silencing genes involved in signaling, ubiquitination and DNA regulation, which could be related to the highly dense symbiont community harbored by this species. Our study provides further evidence of the molecular mechanisms involved in sponge microbial discrimination and aids to understand animal-microbe interactions in early divergent metazoans.