Contribution of Metagenomics to our Understanding of Microbial Processes in Antarctic and Sub-Antarctic Coastal Sediments

High wax ester and triacylglycerol biosynthesis potential in coastal sediments of Antarctic and Subantarctic environments

“…For instance, WS/DGAT sequences assigned to the Actinomycetota phylum were more abundant in OR07 metagenome than in subtidal sediment metagenomes, which is in agreement with the abundance of members of this phylum in the overall bacterial community (2.8 ± 2.6% in subtidal sediment samples, [28]; 14.5% in OR07 intertidal sediment sample, M. Lozada, personal communication). Similarly, members of the Deltaproteobacteria class were more abundant in Subantarctic sediments, while Flavobacteriia was more abundant in Antarctic sediments [28], as it was the case in the taxonomic profile of WS/DGAT homolog sequences. Differences in the relative abundance of homologs identified in Antarctic and Subantarctic sediments were also observed at the OPU level.…”

“…The number of WS/DGAT homolog genes per genome varies in different taxonomic groups and even among species, and therefore the predominance of taxa with low or high ws/dgat gene copy number in the sediment microbial community will influence the relative abundance of these sequences in the metagenomes. Even with these limitations, when comparing the relative abundances of WS/DGAT homolog sequences assigned to different taxa with the microbial community structure of the same subtidal or intertidal sediment samples, not only these taxa were abundant in the community, but they also followed a similar trend [ 28 , 30 ]. For instance, WS/DGAT sequences assigned to the Actinomycetota phylum were more abundant in OR07 metagenome than in subtidal sediment metagenomes, which is in agreement with the abundance of members of this phylum in the overall bacterial community (2.8 ± 2.6% in subtidal sediment samples, [ 28 ]; 14.5% in OR07 intertidal sediment sample, M. Lozada, personal communication).…”

“…Even with these limitations, when comparing the relative abundances of WS/DGAT homolog sequences assigned to different taxa with the microbial community structure of the same subtidal or intertidal sediment samples, not only these taxa were abundant in the community, but they also followed a similar trend [ 28 , 30 ]. For instance, WS/DGAT sequences assigned to the Actinomycetota phylum were more abundant in OR07 metagenome than in subtidal sediment metagenomes, which is in agreement with the abundance of members of this phylum in the overall bacterial community (2.8 ± 2.6% in subtidal sediment samples, [ 28 ]; 14.5% in OR07 intertidal sediment sample, M. Lozada, personal communication). Similarly, members of the Deltaproteobacteria class were more abundant in Subantarctic sediments, while Flavobacteriia was more abundant in Antarctic sediments [ 28 ], as it was the case in the taxonomic profile of WS/DGAT homolog sequences.…”

“…Differences in the relative abundance of homologs identified in Antarctic and Subantarctic sediments were also observed at the OPU level. Distanced almost 1,000 km, Ushuaia Bay and Potter Cove present differences in average seawater temperature, salinity and anthropogenic impact [ 28 , 30 , 35 ], which could be contributors in the selection of specific microbial populations. Furthermore, a potential dispersal barrier of the Antarctic Circumpolar Current is present between both environments [ 79 ].…”

“…In contrast, soils samples contained phylotypes only related to Gram positive actinobacteria, such as Nocardioides , Kribbella , Actinomadura , Streptomyces , Rhodococcus , Dietzia and Thermomonospora [ 26 ]. Microbial communities from coastal sediments of high latitude ecosystems are exposed to multiple sources of stress, including low temperatures and various anthropogenic impacts [ 28 , 29 ]. We hypothesized that the capability to accumulate WE or TAG could contribute to their survival under these extreme conditions, and therefore, this trait would be common among members of these microbial communities.…”