How Mediterranean Sponges React to Friendly Microbes

Jenn Hoskins
8th July, 2024

How Mediterranean Sponges React to Friendly Microbes

The sponge Dysidea avara mounts a complex transcriptomic response to foreign symbionts from Aplysina aerophoba, involving the differential expression of multiple immune receptors like NLRs (a), whereas A. aerophoba shows a minimal response to its own native symbionts, indicating distinct mechanisms for microbial discrimination (b).

Image adapted from: Marulanda-Gomez et al. / CC BY (Source)

Key Findings

  • The study took place at the GEOMAR Helmholtz Centre for Ocean Research Kiel and focused on how sponges differentiate between symbiotic and non-symbiotic microbes
  • Sponges use a variety of immune receptors to recognize and respond to different microbial communities
  • The ability to distinguish between symbiotic and non-symbiotic microbes helps sponges maintain balance and survive in their natural environment
The interaction between sponges and microbes is a fascinating subject that touches on the broader field of animal-microbe relationships. Sponges (phylum Porifera) continuously engage with microbes by filter-feeding from the water column and harboring symbiotic partners within their bodies. Recent research from the GEOMAR Helmholtz Centre for Ocean Research Kiel explores how sponges discriminate between symbiotic and non-symbiotic microbes, shedding light on the underlying mechanisms that allow such differentiation[1]. Sponges are known to take up symbionts at lower rates compared to non-symbiotic seawater microbes, indicating a selective process. Previous genomic studies have revealed that sponges have an extensive array of immune receptors, including NLRs (Nucleotide-binding domain Leucine-rich repeat Receptors), SRCRs (Scavenger Receptor Cysteine-Rich), and GPCRs (G-protein-coupled receptors). These receptors are thought to play crucial roles in microbial recognition and immune responses. The study hypothesized that sponges might use differential expression of these immune receptors to sense and respond to various microbial consortia while filter-feeding. To test this, researchers focused on the transcriptomic responses of two sponge species, Aplysina aerophoba and Dysidea avara, when exposed to microbial consortia extracted from A. aerophoba compared to exposure to general seawater microbes. The sponges were sampled at intervals of 1 hour, 3 hours, and 5 hours for RNA-Seq differential gene expression analysis. The findings of this study align with earlier research that emphasizes the integral role of microbes in animal development and physiology. For instance, it has been established that animal development is not autonomous but requires interactions with the microbial world[2]. This is particularly evident in sponges, which not only filter-feed on microbes but also depend on their symbiotic partners for various physiological functions. The concept of the holobiont, which considers the host and its microbiome as a single evolutionary unit, further supports the idea that the microbial genome can quickly adapt to environmental changes, providing the host organism with a means to survive and thrive under varying conditions[3]. This study advances our understanding of how sponges regulate their immune responses to different microbial communities. By characterizing the transcriptomic responses, the researchers found that sponges indeed exhibit differential expression of immune receptors when encountering different microbial consortia. This ability to distinguish between symbiotic and non-symbiotic microbes likely plays a crucial role in maintaining homeostasis and ensuring the survival of the sponge in its natural habitat. The broader implications of these findings are significant. They contribute to a growing body of evidence that microbes play a fundamental role in the development, physiology, and evolution of animals[4]. Understanding these interactions at a molecular level can provide insights into the mechanisms of immune response and microbial recognition, not only in sponges but potentially in other animals as well. In conclusion, this study from the GEOMAR Helmholtz Centre for Ocean Research Kiel highlights the sophisticated immune mechanisms sponges use to interact with their microbial environment. By leveraging an extensive repertoire of immune receptors, sponges can discriminate between different microbial consortia, ensuring they maintain beneficial symbiotic relationships while effectively managing non-symbiotic microbes. This research not only deepens our understanding of sponge biology but also underscores the intricate and essential relationships between animals and microbes.

GeneticsBiochemMarine Biology

References

Main Study

1) Transcriptomic responses of Mediterranean sponges upon encounter with symbiont microbial consortia

Published 7th July, 2024

https://doi.org/10.1186/s12864-024-10548-z

Related Studies

2) Animal development in the microbial world: Re-thinking the conceptual framework.

https://doi.org/10.1016/bs.ctdb.2020.11.007

3) The hologenome concept of evolution after 10 years.

https://doi.org/10.1186/s40168-018-0457-9

4) Animals in a bacterial world, a new imperative for the life sciences.

https://doi.org/10.1073/pnas.1218525110


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