Spatial metabolomics for symbiotic marine invertebrates

Area of Science:

• * Symbiotic interactions between hosts and microbial symbionts.
• * Metabolomics and spatial analysis of host-microbe relationships.

Background:

• * Microbial symbionts reside in specific host tissues, crucial for host health and nutrient exchange.
• * Traditional methods for measuring metabolite exchange lack spatial resolution.
• * Understanding symbiont localization is key to host-microbe dynamics.

Purpose of the Study:

• * To develop and apply a novel mass spectrometry imaging (MSI) workflow for in situ metabolomics in cnidarians.
• * To investigate host-microbe metabolite exchange and spatial niche dynamics.
• * To uncover mechanisms of symbiont regulation and host metabolic responses.

Main Methods:

• * Development of a mass spectrometry imaging workflow for soft- and hard-bodied cnidarians.
• * In situ analysis of host and symbiont metabolomes without isotopic labeling or decalcification.
• * Spatial mapping of metabolites to understand their distribution and function.

Main Results:

• * Cnidarian hosts regulate microalgal symbiont acquisition/rejection via ceramides in the gastrovascular cavity lining.
• * Resident symbionts are found in light-exposed tentacles, facilitating photosynthate production.
• * Metabolite spatial patterns indicate that symbiont identity influences host metabolism.

Conclusions:

• * Mass spectrometry imaging offers critical functional insights into host-microbe interactions, surpassing bulk analyses.
• * Ceramides play a role in cnidarian symbiont selectivity and localization.
• * Spatial metabolomics reveals the intricate interplay between symbiont presence and host metabolic processes.