The fitness landscape of the African Salmonella Typhimurium ST313 strain D23580 reveals unique properties of the pBT1 plasmid

English version

Autoři: Rocío Canals ^aff001; Roy R. Chaudhuri ^aff002; Rebecca E. Steiner ^aff003; Siân V. Owen ^aff001; Natalia Quinones-Olvera ^aff005; Melita A. Gordon ^aff006; Michael Baym ^aff005; Michael Ibba ^aff003; Jay C. D. Hinton ^aff001
Působiště autorů: Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom ^aff001; Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, United Kingdom ^aff002; Department of Microbiology, The Ohio State University, Columbus, Ohio, United States of America ^aff003; Center for RNA Biology, The Ohio State University, Columbus, Ohio, United States of America ^aff004; Department of Biomedical Informatics, Harvard Medical School, Boston, Massachusetts, United States of America ^aff005; Institute of Infection and Global Health, University of Liverpool, Liverpool, United Kingdom ^aff006; Malawi-Liverpool-Wellcome Trust Clinical Research Programme, University of Malawi College of Medicine, Blantyre, Malawi, Central Africa ^aff007
Vyšlo v časopise: The fitness landscape of the African Salmonella Typhimurium ST313 strain D23580 reveals unique properties of the pBT1 plasmid. PLoS Pathog 15(9): e32767. doi:10.1371/journal.ppat.1007948
Kategorie: Research Article
doi: https://doi.org/10.1371/journal.ppat.1007948

Souhrn

We have used a transposon insertion sequencing (TIS) approach to establish the fitness landscape of the African Salmonella enterica serovar Typhimurium ST313 strain D23580, to complement our previous comparative genomic and functional transcriptomic studies. We used a genome-wide transposon library with insertions every 10 nucleotides to identify genes required for survival and growth in vitro and during infection of murine macrophages. The analysis revealed genomic regions important for fitness under two in vitro growth conditions. Overall, 724 coding genes were required for optimal growth in LB medium, and 851 coding genes were required for growth in SPI-2-inducing minimal medium. These findings were consistent with the essentiality analyses of other S. Typhimurium ST19 and S. Typhi strains. The global mutagenesis approach also identified 60 sRNAs and 413 intergenic regions required for growth in at least one in vitro growth condition. By infecting murine macrophages with the transposon library, we identified 68 genes that were required for intra-macrophage replication but did not impact fitness in vitro. None of these genes were unique to S. Typhimurium D23580, consistent with a high conservation of gene function between S. Typhimurium ST313 and ST19 and suggesting that novel virulence factors are not involved in the interaction of strain D23580 with murine macrophages. We discovered that transposon insertions rarely occurred in many pBT1 plasmid-encoded genes (36), compared with genes carried by the pSLT-BT virulence plasmid and other bacterial plasmids. The key essential protein encoded by pBT1 is a cysteinyl-tRNA synthetase, and our enzymological analysis revealed that the plasmid-encoded CysRS^pBT1 had a lower ability to charge tRNA than the chromosomally-encoded CysRS^chr enzyme. The presence of aminoacyl-tRNA synthetases in plasmids from a range of Gram-negative and Gram-positive bacteria suggests that plasmid-encoded essential genes are more common than had been appreciated.

Klíčová slova:

Biosynthesis – Genomic libraries – Macrophages – Plasmid construction – Salmonella typhimurium – Transposable elements – Salmonella typhi – Aminoacyl-tRNA synthetases

Zdroje

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