The genome of deep-sea vent chemolithoautotroph Thiomicrospira crunogena XCL-2

This is an open-access article distributed under the terms of the Creative Commons Public Domain dedication. The definitive version was published in PLoS Biology 4 (2006): e383, doi:10.1371/journal.pbio.0040383.Presented here is the complete genome sequence of Thiomicrospira crunogena XCL-2, representative of ubiquitous chemolithoautotrophic sulfur-oxidizing bacteria isolated from deep-sea hydrothermal vents. This gammaproteobacterium has a single chromosome (2,427,734 base pairs), and its genome illustrates many of the adaptations that have enabled it to thrive at vents globally. It has 14 methyl-accepting chemotaxis protein genes, including four that may assist in positioning it in the redoxcline. A relative abundance of coding sequences (CDSs) encoding regulatory proteins likely control the expression of genes encoding carboxysomes, multiple dissolved inorganic nitrogen and phosphate transporters, as well as a phosphonate operon, which provide this species with a variety of options for acquiring these substrates from the environment. Thiom. crunogena XCL-2 is unusual among obligate sulfur-oxidizing bacteria in relying on the Sox system for the oxidation of reduced sulfur compounds. The genome has characteristics consistent with an obligately chemolithoautotrophic lifestyle, including few transporters predicted to have organic allocrits, and Calvin-Benson-Bassham cycle CDSs scattered throughout the genome.This work was performed under the auspices of the United States Department of Energy by Lawrence Livermore National Laboratory, University of California, under contract W-7405-ENG-48. Genome closure was funded in part by a University of South Florida Innovative Teaching Grant (to KMS). KMS, SKF, and CAK gratefully acknowledge support from the United States Department of Agriculture Higher Education Challenge Grants Program (Award # 20053841115876). SMS kindly acknowledges support through a fellowship received from the Hanse Wissenschaftskolleg in Delmenhorst, Germany (http://www.h-w-k.de). MH was supported by a Woods Hole Oceanographic Institution postdoctoral scholarship