ABSTRACTWe determined a significant fraction of the genome sequence of a representative ofThiovulum, the uncultivated genus of colorless sulfurEpsilonproteobacteria, by analyzing the genome sequences of four individual cells collected from phototrophic mats from Elkhorn Slough, California. These cells were isolated utilizing a microfluidic laser-tweezing system, and their genomes were amplified by multiple-displacement amplification prior to sequencing.Thiovulumis a gradient bacterium found at oxic-anoxic marine interfaces and noted for its distinctive morphology and rapid swimming motility. The genomic sequences of the four individual cells were assembled into a composite genome consisting of 221 contigs covering 2.083 Mb including 2,162 genes. This single-cell genome represents a genomic view of the physiological capabilities of isolatedThiovulumcells.Thiovulumis the second-fastest bacterium ever observed, swimming at 615 μm/s, and this genome shows that this rapid swimming motility is a result of a standard flagellar machinery that has been extensively characterized in other bacteria. This suggests that standard flagella are capable of propelling bacterial cells at speeds much faster than typically thought. Analysis of the genome suggests that naturally occurringThiovulumpopulations are more diverse than previously recognized and that studies performed in the past probably address a wide range of unrecognized genotypic and phenotypic diversities ofThiovulum. The genome presented in this article provides a basis for future isolation-independent studies ofThiovulum, where single-cell and metagenomic tools can be used to differentiate between differentThiovulumgenotypes.
Three Draft Single-Cell Genome Sequences of Novel SAR324 Strains Isolated from the Abyssopelagic Southern Ocean
