Epigenetics of Sulfate Reducing Bacteria Under Copper Stress

Author: Payal Thakur, Department of Chemical and Biological Engineering (Equal contribution)

Co-Author: Shailabh Rauniyar, Department of Chemical and Biological Engineering (Equal contribution)

Contributor: Abhilash Kumar Tripathi, Department of Chemical and Biological Engineering

Contributor: Priya Saxena, Department of Chemical and Biological Engineering

Mentor: Dr. Rajesh Sani, Department of Chemical and Biological Engineering

Epigenetics is a mechanism of gene regulation without changing the DNA sequence, which is heritable in nature. Epigenetic regulation is poorly studied in prokaryotes and is associated with DNA methylation that regulates the DNA-protein interaction in bacteria which often plays a role in phenotypic variations. Our study focuses on biofilm-forming Desulfovibrio alaskensis G20, which are sulfate-reducing bacteria (SRB), thereby producing hydrogen sulfide as an end product. Hydrogen sulfide is responsible for metal corrosion which is directly proportional to the biofilms formation by the SRB on metal surfaces. Preliminary experiments were performed on the planktonic SRB cells grown under variable bioavailable copper conditions (0, 5, 15, and 30µM) in anaerobic serum bottles. SRB cell density decreased with an increase in copper ion concentration. The DNA extraction was carried out, followed by the quality and quantity assessment. The samples were subjected to Whole-Genome Bisulfite Sequencing (WGBS) for epigenetic profiling. The sequencing data were processed in-house using the Galaxy platform, wherein Bismark workflow was set up to map the m⁵C base modifications. Our results show more than a 20% differential m⁵C percentage methylation in the genes responsible for biofilm formation across CpG, CHG and CHH islands. The data is crucial to investigate the role of epigenetics in the biocorrosion of a metal surface by SRB biofilms.