Heavy Metal Stress Tolerance by Serratia nematodiphila sp. MB307: Insights from Mass Spectrometry-based Proteomics

Background: Heavy metals impact living organism deleteriously when exceed the required limits. Their remediation by bacteria is a much pursued area of environmental research. In this study, we explored the quantitative changes for four heavy metals (Cadmium, Chromium, Zinc, Copper), on global and membrane proteome of gram negative S. nematodiphila MB307. This is a versatile bacterium, isolated from rhizosphere of heavy metal tolerating plant and equipped with characteristics ranging from useful biopeptide production to remediation of metals. Methods: We explored changes in its static end products of coding DNA sequences i.e. proteins after 24 incubation under metal stress, using LC-MS/MS. Data analysis was done using MaxQuant software coupled with Perseus package. Results: Up and downregulated protein fractions consisted prominently of chaperones, membrane integrity proteins, mobility or transporter proteins. Comparative analysis with previously studied bacteria and functional contribution of these proteins in metal stress offers evidence for survival of S. nematodiphila under high concentrations of selected metals. Conclusion: The outcomes validate that this soil derived bacterium is well attuned to remove these metals from soil, water and may be additionally useful for boosting phytoremediation of metals. This study delivers interesting insights and overlays ground for further investigations into mechanistic activity of this bacterium under pollutant stress.