Insight into heavy metal resistome of soil psychrotolerant bacteria originating from King George Island (Antarctica)

The presence of heavy metals in Antarctica is an emerging issue, especially as (bio)weathering of metal-containing minerals occurs and human influence is more and more visible in this region. Chemical analysis of three soil samples collected from the remote regions of King George Island (Antarctica) revealed the presence of heavy metals (mainly copper, mercury, and zinc) at relatively high concentrations. Physiological characterization of over 200 heavy metal-resistant, psychrotolerant bacterial strains isolated from the Antarctic soil samples was performed. This enabled an insight into the heavy metal resistome of these cultivable bacteria and revealed the prevalence of co-resistance phenotypes. All bacteria identified in this study were screened for the presence of selected heavy metal-resistance genes, which resulted in identification of arsB (25), copA (3), czcA (33), and merA (26) genes in 62 strains. Comparative analysis of their nucleotide sequences provided an insight into the diversity of heavy metal-resistance genes in Antarctic bacteria.