Author: Pamela  Engelberts,   (University of Queensland)

Designation: 

Description:
Marine sponges are essential for the survival and productivity of coral reefs, and frequently host a diverse and species-specific community of microorganisms. Although these microbes are thought to contribute to host health, in-depth characterisation of each taxa remains challenging, with many sponge species hosting over 3000 distinct microbial species. Ianthella basta, an abundant and widespread reef sponge, has recently emerged as a model organism for sponge symbiosis research. This sponge harbours only three dominant symbionts: a Thaumarchaeotum, a Gammaproteobacterium, and an Alphaproteobacterium, with metagenome-assembled genomes (MAGs) recovered for the first two symbionts. Here, we retrieved the genome of the Alphaproteobacterium (amongst other less abundant taxa), enabling the detailed characterisation of the metabolic potential of the entire I. basta microbiome. Furthermore, knowing how these dominant symbionts are transmitted (i.e. vertically or environmentally) throughout the sponge’s life cycle is vital to understanding how they mediate important developmental stages. To further establish I. basta as a model species, we successfully spawned I. basta in aquaria and applied 16S rRNA gene amplicon sequencing, fluorescence in situ hybridisation (FISH), and transmission electron microscopy (TEM) to unravel the mode of transmission for each of the dominant symbionts throughout the sponge’s life cycle. We show that all dominant symbionts are vertically transmitted from the parent to the offspring, suggesting an obligate relationship between the microbes and their host.

Category: Scientific Program Abstract > Special Sessions > SS40 Host-microbiome interactions of marine organisms