Prokaryotic Diversity and Community Patterns in Antarctic Continental Shelf Sponges

Abstract

Marine sponges (Phylum Porifera) are globally distributed within marine and freshwater ecosystems. In addition, sponges host dense and diverse prokaryotic communities, which are potential sources of novel bioactive metabolites and other complex compounds. Those sponge-derived natural products can span a broad spectrum of bioactivities, from antibacterial and antifungal to antitumor and antiviral compounds. However, most analyses concerning sponge-associated prokaryotes have mainly focused on conveniently accessible relatively shallow sampling locations for sponges. Hence, knowledge of community composition, host-relatedness and biotechnological potential of prokaryotic associations in temperate and cold-water sponges from greater depths (mesophotic to mesopelagic zones) is still scarce. Therefore, we analyzed the prokaryotic community diversity of four phylogenetically divergent sponge taxa from mesophotic to mesopelagic depths of Antarctic shelf at different depths and locations in the region of the South Shetland Islands using 16S rRNA gene ampliconbased sequencing. In addition, we predicted functional profiles applying Tax4Fun from metagenomic 16S rRNA gene data to estimate their biotechnological capability and possible roles as sources of novel bioactive compounds. We found indications that cold and deep-water sponges exhibit host-specific prokaryotic communities, despite different sampling sites and depths. Functional prediction analysis suggests that the associated prokaryotes may enhance the roles of sponges in biodegradation processes of xenobiotics and their involvement in the biosynthesis of secondary metabolites.

Host species determine symbiotic community composition in Antarctic sponges (Porifera: Demospongiae)

“…Contrastingly, these phyla represent a much lower percentage in Antarctic sponges (0.0005-0.4%). Our results are in agreement with previous studies carried out in Antarctica (Rodríguez-Marconi et al 2015; Cárdenas et al 2018; Steinert et al 2019; Moreno-Pino et al 2020). Other widely described but less abundant phyla associated with sponges from other geographical areas are Poribacteria and PAUC34f (Moitinho-Silva et al 2017b).…”

“…Other widely described but less abundant phyla associated with sponges from other geographical areas are Poribacteria and PAUC34f (Moitinho-Silva et al 2017b). These bacterial groups were not detected neither in the Antarctic sponges from the present study nor in other species previously studied in Antarctica (Rodríguez-Marconi et al 2015; Cárdenas et al 2018; Steinert et al 2019; Cárdenas et al 2019; Moreno-Pino et al 2020). These phyla have been found overrepresented in HMA over LMA sponges and can be used as “HMA/LMA indicators” (Moitinho-Silva et al 2017b; Glasl et al 2018).…”

“…Classes Gamma- and Alphaproteobacteria dominate bacterial assemblages in association with marine sponges from different biotopes (Thomas et al 2016; Moitinho-Silva et al 2017a; Pita et al 2018; Cleary et al 2019). These classes also dominate Antarctic sponges as previously reported on Antarctic marine shallow (Webster et al 2004; Rodríguez-Marconi et al 2015; Cárdenas et al 2018; Cárdenas et al 2019) and deep waters (Steinert et al 2019) with Bacteroidetes also as important members in terms of number of OTUs recovered (n = 1,174) and in relative abundance (10%). The presence of the phylum Nitrospirae (>3% in relative abundance) in one of the sponges analyzed ( S. antarcticus ) is particularly noticeable.…”

“…This work describes the bacterial and archaeal diversity and the community composition of four Antarctic sponge species, revealing that the sponges had a microbial signature different from the richer and diverse seawater community. In Antarctica, due to the difficult access to this region, only few studies have made comprehensive descriptions of microbial symbionts of marine sponges (Webster et al 2004; Rodríguez-Marconi et al 2015; Cárdenas et al 2018; Steinert et al 2019; Cárdenas et al 2019; Moreno-Pino et al 2020). However, this is the first study that assesses the microbial communities associated to Antarctic sponges using high throughput sequencing, considering biological replications and covering a spatial scale over 650 km.…”

“…There have been several approximations to unravel the composition of Antarctic microbial communities associated to sponges, but primarily focused on eukaryotic microorganisms (Bavestrello et al 2000; Cerrano et al 2000; Cerrano et al 2004; Henríquez et al 2014). However, the most comprehensive studies describing microbial communities associated to Antarctic sponges using classic and high throughput sequencing described a total prokaryotic composition of 26 bacterial and 3 archaeal phyla and the presence of 8 eukaryotic groups (Webster et al 2004; Rodríguez-Marconi et al 2015; Cárdenas et al 2018; Steinert et al 2019; Cárdenas et al 2019). Recently, functional metagenomics has been used to characterize the community composition and metabolic potential of microbiomes of two Antarctic sponges (Moreno-Pino et al 2020).…”