Genomic and physiological characterization and description of Marinobacter gelidimuriae sp. nov., a psychrophilic, moderate halophile from Blood Falls, an antarctic subglacial brine

Abstract

Antarctic subice environments are diverse, underexplored microbial habitats. Here, we describe the ecophysiology and annotated genome of a Marinobacter strain isolated from a cold, saline, iron-rich subglacial outflow of the Taylor Glacier, Antarctica. This strain (BF04_CF4) grows fastest at neutral pH (range 6-10), is psychrophilic (range: 0°C-20°C), moderately halophilic (range: 0.8%-15% NaCl) and hosts genes encoding potential low temperature and high salt adaptations. The predicted proteome suggests it utilizes fewer charged amino acids than a mesophilic Marinobacter strain. BF04_CF4 has increased concentrations of membrane unsaturated fatty acids including palmitoleic (33%) and oleic (27.5%) acids that may help maintain cell membrane fluidity at low temperatures. The genome encodes proteins for compatible solute biosynthesis and transport, which are known to be important for growth in saline environments. Physiological verification of predicted metabolic functions demonstrate BF04_CF4 is capable of denitrification and may facilitate iron oxidation. Our data indicate that strain BF04_CF4 represents a new Marinobacter species, Marinobacter gelidimuriae sp. nov., that appears well suited for the subglacial environment it was isolated from. Marinobacter species have been isolated from other cold, saline environments in the McMurdo Dry Valleys and permanently cold environments globally suggesting that this lineage is cosmopolitan and ecologically relevant in icy brines.

Microbial Assemblages in Pressurized Antarctic Brine Pockets (Tarn Flat, Northern Victoria Land): A Hotspot of Biodiversity and Activity

“…Polar habitats harbor diverse and metabolically active microbial communities [17,56,57,58]. To the best of our knowledge, this is the first comprehensive study which includes quali-quantitative and metabolic analyses of microbial communities inhabiting hypersaline brines from a perennially ice-covered lake in the Tarn Flat area.…”

“…To the best of our knowledge, this is the first comprehensive study which includes quali-quantitative and metabolic analyses of microbial communities inhabiting hypersaline brines from a perennially ice-covered lake in the Tarn Flat area. Recently, Chua et al [58] defined the Antarctic briny environments as liquid oases for microbial life. Hypersaline brine lenses are unique aquatic systems that are thought not to undergo changes via external influence over geological timescales [59].…”

“…The TF brines hosted isolates belonging to the genus Psychrobacter (within Gammaproteobacteria) and were able to grow up to 17–19% in NaCl (data not shown). That genus, in addition to Marinobacter , appears to be cosmopolitan in cold Antarctic brines [5,17,19,58,104] and hypersaline Antarctic lakes [105]. Halophilic species have been previously retrieved in Antarctica in samples of geothermal and saline soils [106].…”

Isolation, characterization and optimization of EPSs produced by a cold-adaptedMarinobacterisolate from Antarctic seawater

“…Cold-adapted Marinobacter from Antarctica have been poorly reported, although two novel halotolerant species from Antarctic sediments, i.e. Marinobacter antarcticus Liu et al (Liu et al 2012) and Marinobacter guineae Montes et al (Montes et al 2008), and brines (Chua et al 2018) have been described. Further, at the time of writing, no report exists on EPS-producing cold-adapted Marinobacter isolates.…”

Microbial diversity of an Antarctic subglacial community and high‐resolution replicate sampling inform hydrological connectivity in a polar desert

“…(OTU25) shares 100% 16S rRNA gene sequence identity to M. gelidimuriea which was cultivated directly from the 2004 EMB collection (Chua et al, ). This halotolerant, psychrophile is a member of an apparently cosmopolitan lineage of Marinobacter , prevalent throughout the MDV brines (Chua et al, ) and is closely related to isolates from both the east and west lobe of Lake Bonney (Ward and Priscu, ). Marinobacter sequences were also abundant in 30 m WLB samples reported by Kwon et al .…”