Award: OCE-1260710

Moyer, PI (NSF OCE-1260710, $302,818, 04/13 to 12/17). Project Title - RUI: Iron-oxidizing Bacteria from the Okinawa Trough Deep Subsurface Biosphere. We have documented the occurrence of unique Zetaproteobacteria residing in the deep subsurface as part of the Integrated Ocean Drilling Program's (IODP) expedition 331 to hydrothermally active mounds in the Okinawa Trough. Through the use of single amplified genomes (SAGs), we have extended the metabolic potential of another understudied group of subsurface microbes, the Chloroflexi. These microbes are frequently detected in the subsurface biosphere, though their metabolic capabilities have remained elusive. In contrast to previously examined Chloroflexi SAGs, our genomes (several are from the order Anaerolineales) were recovered from a hydrothermally driven system and therefore provide a unique window into the metabolic potential of this type of habitat. In addition, a reductive dehalogenase gene (rdhA) has now been directly linked to marine subsurface Chloroflexi, suggesting that reductive dehalogenation is not limited to the class Dehalococcoidia as previously thought. This discovery expands the nutrient-cycling and metabolic potential present within the deep subsurface and provides functional gene information relating to this enigmatic group. Finally, we also conducted an analysis of the biogeography of Thermococcus isolates originating from the subsurface. Amplified fragment length polymorphism (AFLP) analysis and multilocus sequence typing (MLST) were used to resolve genomic differences in 90 isolates of Thermococcus, making biogeographic patterns and evolutionary relationships apparent. The biodiversity identified in our Thermococcus isolates and presence of distinct lineages within the same vent site suggests the utilization of varying ecological niches in this genus. In addition to resolving their biogeographic patterns, this study has raised new questions about the closely related Pyrococcus genus. To better understand what functional genes and metabolic traits are found in the genomes of our Thermococcus isolates, we have used Illumina sequencing of representative members of all clades with an eventual goal of establishing a baseline of common genes, i.e., characterizing the Thermococcus pan-genome. A postdoctoral researcher, four graduate students, and six undergraduates were supported. Three publications have resulted from this project and are cited below (another is currently in preparation). In addition, seven presentations have been made at both national and international scientific meetings based on results from this project. Refs Cited: Fullerton, H. and C. L. Moyer. 2016. Comparative single-cell genomics of Chloroflexi from the Okinawa Trough deep subsurface biosphere. Appl. Environ. Microbiol. 82:3000-3008. doi:10.1128/AEM.00624-16. Price, M. T., H. Fullerton, and C. L. Moyer. 2015. Biogeography and evolution of Thermococcus isolates from hydrothermal vent systems of the Pacific. Front. Microbiol. 6:968. doi:10.3389/fmicb.2015.00968. Yanagawa, K., T. Nunoura, S. M. McAllister, M. Hirai, A. Breuker, L. Brandt, C. House, C. L. Moyer, J.-L. Birrien, K. Aoike, M. Sunamura, T. Urabe, M. J. Mottl and K. Takai. 2013. The first microbiological contamination assessment by deep-sea drilling and coring by the D/V Chikyu at the Iheya North hydrothermal field in the Mid-Okinawa Trough (IODP Expedition 331). Front. Microbiol. 4:327. doi:10.3389/fmicb.2013.00327. Last Modified: 04/12/2018 Submitted by: Craig L Moyer