Identification of genes involved in salt adaptation in the archaeonMethanosarcina mazeiGö1 using genome-wide gene expression profiling

Abstract

Methanosarcina mazei is a nonhalophilic methanogen that can adapt to 800 mM NaCl. Microarray studies have been used to examine the effect of elevated salinities on the regulation of gene expression in M. mazei. Eighty-four genes of different functional categories, such as solute transport and biosynthesis, Na(+) export, stress response, ion, protein and phosphate transport, metabolic enzymes, regulatory proteins, DNA-modification systems, and cell-surface modulators, were found to be stronger expressed at high salinities. Moreover, 10 genes encoding different metabolic functions including potassium uptake and ATP synthesis were reduced in expression under high salt. The overall expression profiles suggest that M. mazei is able to adapt to high salinities by multiple upregulation of many different cellular functions including protective pathways such as solute transport and biosynthesis, import of phosphate, export of Na(+), and upregulation of pathways for modification of DNA and cell surface architecture.

Role of Polyphosphates in Microbial Adaptation to Extreme Environments

“…Within the HAAW microbial ecosystem, Archaea comprise an important component of the community (13,18). Methanosarcina mazei Gö adapts to concentrations of NaCl up to 1 M by inducing genes that encode a phosphate transport system, which results in the increase of transport and synthesis of polyP (64).…”

Global Transcriptional, Physiological, and Metabolite Analyses of the Responses of Desulfovibrio vulgaris Hildenborough to Salt Adaptation

“…Genome-wide transcriptional analyses of salt and/or osmotic stress responses have been performed for many different bacteria and archaea, including Escherichia coli (60), Bacillus subtilis (52), Shewanella oneidensis MR-1 (34), Yersinia pestis (19), Pseudomonas aeruginosa (1), Sinorhizobium meliloti (16), and Methanosarcina mazei (45,51). A broad set of differentially expressed genes was observed in these studies.…”

Contribution of Transcriptomics to Systems-Level Understanding of MethanogenicArchaea

“…In M. mazei , the most highly differentially expressed gene during sodium chloride stress was a hypothetical protein with no known homologues outside of the Methanosarcina genus [35]. The second most differentially expressed gene encoded a putative hypothetical protein.…”

“…This indicates that some novel salt adaptive mechanisms may be present in M. mazei . However, conventional salt adaptive mechanisms were also evident in M. mazei with the upregulation of transcript levels related to solute transport and biosynthesis and Na + export in response to high sodium chloride concentrations [35]. Interestingly, among nonmarine methanogens, their sensitivity to sodium levels is rather variable from highly to less sensitive [36].…”