AUTHOR=Kallscheuer Nicolai , Wiegand Sandra , Kohn Timo , Boedeker Christian , Jeske Olga , Rast Patrick , Müller Ralph-Walter , Brümmer Franz , Heuer Anja , Jetten Mike S. M. , Rohde Manfred , Jogler Mareike , Jogler Christian 

TITLE=Cultivation-Independent Analysis of the Bacterial Community Associated With the Calcareous Sponge Clathrina clathrus and Isolation of Poriferisphaera corsica Gen. Nov., Sp. Nov., Belonging to the Barely Studied Class Phycisphaerae in the Phylum Planctomycetes

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.602250

DOI=10.3389/fmicb.2020.602250

ISSN=1664-302X

ABSTRACT=<p>Marine ecosystems serve as global carbon sinks and nutrient source or breeding ground for aquatic animals. Sponges are ancient parts of these important ecosystems and can be found in caves, the deep-sea, clear waters, or more turbid environments. Here, we studied the bacterial community composition of the calcareous sponge <italic>Clathrina clathrus</italic> sampled close to the island Corsica in the Mediterranean Sea with an emphasis on planctomycetes. We show that the phylum <italic>Planctomycetes</italic> accounts for 9% of the <italic>C. clathrus</italic>-associated bacterial community, a 5-fold enrichment compared to the surrounding seawater. Indeed, the use of <italic>C. clathrus</italic> as a yet untapped source of novel planctomycetal strains led to the isolation of strain KS4<sup>T</sup>. The strain represents a novel genus and species within the class <italic>Phycisphaerae</italic> in the phylum <italic>Planctomycetes</italic> and displays interesting cell biological features, such as formation of outer membrane vesicles and an unexpected mode of cell division.</p>