SREL Reprint #3509

Metagenomics-guided survey, isolation, and characterization of uranium resistant microbiota from the Savannah River Site, USA

Rajneesh Jaswal1, Ashish Pathak1, Bobby Edwards III1, Robert Lewis III1, John C. Seaman2,
Paul Stothard3, Kirill Krivushin3, Jochen Blom4 , Oliver Rupp4, and Ashvini Chauhan1

1School of the Environment, 1515 S. MLK Blvd., Suite 305B, Building FSHSRC,
Florida A&M University, Tallahassee, FL 32307, USA
2Savannah River Ecology Laboratory, The University of Georgia. PO Drawer E, Aiken, SC 29802, USA
3Department of Agricultural, Food and Nutritional Science,
University of Alberta, Edmonton, AB T6G2P5, Canada
4Bioinformatics and Systems Biology, Justus-Liebig-University Giessen, 35392 Giessen, Germany

Abstract: Despite the recent advancements in culturomics, isolation of the majority of environmental microbiota performing critical ecosystem services, such as bioremediation of contaminants, remains elusive. Towards this end, we conducted a metagenomics-guided comparative assessment of soil microbial diversity and functions present in uraniferous soils relative to those that grew in diffusion chambers (DC) or microbial traps (MT), followed by isolation of uranium (U) resistant microbiota. Shotgun metagenomic analysis performed on the soils used to establish the DC/MT chambers revealed Proteobacterial phyla and Burkholderia genus to be the most abundant among bacteria. The chamber-associated growth conditions further increased their abundances relative to the soils. Ascomycota was the most abundant fungal phylum in the chambers relative to the soils, with Penicillium as the most dominant genus. Metagenomics-based taxonomic findings completely mirrored the taxonomic composition of the retrieved isolates such that the U-resistant bacteria and fungi mainly belonged to Burkholderia and Penicillium species, thus confirming that the chambers facilitated proliferation and subsequent isolation of specific microbiota with environmentally relevant functions. Furthermore, shotgun metagenomic analysis also revealed that the gene classes for carbohydrate metabolism, virulence, and respiration predominated with functions related to stress response, membrane transport, and metabolism of aromatic compounds were also identified, albeit at lower levels. Of major note was the successful isolation of a potentially novel Penicillium species using the MT approach, as evidenced by whole genome sequence analysis and comparative genomic analysis, thus enhancing our overall understanding on the uranium cycling microbiota within the tested uraniferous soils.

Keywords: uranium resistance; metagenomics; whole genome sequence; comparative genomics;
Burkholderia; Penicillium; diffusion chamber; microbial trap

SREL Reprint #3509

Jaswal, R., A. Pathak, B. Edwards III, R. Lewis III, J. C. Seaman, P. Stothard, K. Krivushin, J. Blom, O. Rupp, and A. Chauhan. 2019. Metagenomics-guided survey, isolation, and characterization of uranium resistant microbiota from the Savannah River Site, USA. Genes 10(5): 1-22.

This information was provided by the University of Georgia's Savannah River Ecology Laboratory (srel.uga.edu).