AUTHOR=Burgunter-Delamare Bertille , Rousvoal Sylvie , Legeay Erwan , Tanguy Gwenn , Fredriksen Stein , Boyen Catherine , Dittami Simon M. 

TITLE=The Saccharina latissima microbiome: Effects of region, season, and physiology

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2023

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.1050939

DOI=10.3389/fmicb.2022.1050939

ISSN=1664-302X

ABSTRACT=<sec><title>Introduction</title><p><italic>Saccharina latissima</italic> is a canopy-forming species of brown algae and, as such, is considered an ecosystem engineer. Several populations of this alga are exploited worldwide, and a decrease in the abundance of <italic>S. latissima</italic> at its southern distributional range limits has been observed. Despite its economic and ecological interest, only a few data are available on the composition of microbiota associated with <italic>S. latissima</italic> and its role in algal physiologyn.</p></sec><sec><title>Methods</title><p>We studied the whole bacterial community composition associated with <italic>S. latissima</italic> samples from three locations (Brittany, Helgoland, and Skagerrak) by 16S metabarcoding analyses at different scales: algal blade part, regions, season (at one site), and algal physiologic state.</p></sec><sec><title>Results and Discussion</title><p>We have shown that the difference in bacterial composition is driven by factors of decreasing importance: (i) the algal tissues (apex/meristem), (ii) the geographical area, (iii) the seasons (at the Roscoff site), and (iv) the algal host’s condition (healthy vs. symptoms). Overall, <italic>Alphaproteobacteria</italic>, <italic>Gammaproteobacteria</italic>, and <italic>Bacteroidia</italic> dominated the general bacterial communities. Almost all individuals hosted bacteria of the genus <italic>Granulosicoccus</italic>, accounting for 12% of the total sequences, and eight additional core genera were identified. Our results also highlight a microbial signature characteristic for algae in poor health independent of the disease symptoms. Thus, our study provides a comprehensive overview of the <italic>S. latissima</italic> microbiome, forming a basis for understanding holobiont functioning.</p></sec>