title: Chlorobaculum tepidum TLS displays a complex transcriptional response to sulfide addition.
abstract: Chlorobaculum tepidum is a green sulfur bacterium (GSB) that is a model system for phototrophic sulfur oxidation. Despite over 2 decades of research, conspicuous gaps exist in our understanding of its electron donor metabolism and regulation. RNA sequencing (RNA-seq) was used to provide a global picture of the C. tepidum transcriptome during growth on thiosulfate as the sole electron donor and at time points following the addition of sulfide to such a culture. Following sulfide addition, 121 to 150 protein-coding genes displayed significant changes in expression depending upon the time point. These changes included a rapid decrease in expression of thiosulfate and elemental sulfur oxidation genes. Genes and gene loci with increased expression included CT1087, encoding a sulfide:quinone oxidoreductase required for growth in high sulfide concentrations; a polysulfide reductase-like complex operon, psrABC (CT0496 to CT0494); and, surprisingly, a large cluster of genes involved in iron acquisition. Finally, two genes that are conserved as a cassette in anaerobic bacteria and archaea, CT1276 and CT1277, displayed a strong increase in expression. The CT1277 gene product contains a DNA-binding domain, suggesting a role for it in sulfide-dependent gene expression changes.
authors.affiliation: College of Earth, Ocean, and Environment and Delaware Biotechnology Institute, University of Delaware, Newark, DE, USA.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Eddie
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Hanson
mesh_terms: D019414:Chlorobi / Q000187:drug effects* / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D053858:Metabolic Networks and Pathways / Q000235:genetics; D013440:Sulfides / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D059467:Transcriptome
chemical_list: D013440:Sulfides