Speaker
Description
The brown alga Ascophyllum nodosum and its microbiota form a dynamic functional entity named holobiont. The microbial partners play a role in seaweed health by producing bioactive compounds crucial for normal morphology and development. Ascophyllum is also an important raw material to produce plant biostimulants. However, we need more knowledge about the microbiome of Ascophyllum to understand the role of symbionts in bioactive molecule production. Within the SEABIOZ project, we are studying the roles of microorganisms associated with Ascophyllum through multi-omics approaches. By combining long-read and short-read metabarcoding approaches, we examined the composition of the microbiome (bacteria, archaea, fungi, and other eukaryotes) over a year, including algal tissue, and site as covariables. We identified three major player symbionts as there are almost always associated with the host and found in high relative abundance: the two fungi Mycophycias ascophylli and Moheitospora sp., and the bacterium Granulosicoccus sp.. Moheitospora sp. and Granulosicoccus sp. were successfully cultured and sequenced. However, Mycophycias ascophylli is still uncultivable and to obtain its genome sequence, we used Illumina metagenome assembly, real-time read enrichment during long-read metagenome re-sequencing, and hybrid assemblies. The analysis of microbial genomes provided access to their potential metabolic and biological functions in the holobiont ecosystem.
