Virus-host interactions are regulated by complex coevolutionary dynamics. In Streptococcus pneumoniae, phase-variable type I restriction-modification (R-M) systems are part of the core genome. We hypothesized that the ability of the R-M systems to switch between six target DNA specificities also has a key role in preventing the spread of bacteriophages. Using the streptococcal temperate bacteriophage SpSL1, we show that the variants of both the SpnIII and SpnIV R-M systems are able to restrict invading bacteriophage with an efficiency approximately proportional to the number of target sites in the bacteriophage genome. In addition to restriction of lytic replication, SpnIII also led to abortive infection in the majority of host cells. During lytic infection, transcriptional analysis found evidence of phagehost interaction through the strong upregulation of the nrdR nucleotide biosynthesis regulon. During lysogeny, the phage had less of an effect on host gene regulation. This research demonstrates a novel combined bacteriophage restriction and abortive infection mechanism, highlighting the importance that the phase-variable type I R-M systems have in the multifunctional defense against bacteriophage infection in the respiratory pathogen S. pneumoniae.
Methylation warfare: interaction of pneumococcal bacteriophages with their host / Furi L; Crawford LA; Rangel-Pineros G; Manso AS; De Ste Croix M; Haigh RD; Kwun MJ; Engelsen Fjelland K; Gilfillan GD; Bentley SD; Croucher NJ; Clokie MR; Oggioni MR. - In: JOURNAL OF BACTERIOLOGY. - ISSN 0021-9193. - ELETTRONICO. - 201:19(2019), pp. 1-16. [10.1128/JB.00370-19]
Methylation warfare: interaction of pneumococcal bacteriophages with their host
Oggioni MR
2019
Abstract
Virus-host interactions are regulated by complex coevolutionary dynamics. In Streptococcus pneumoniae, phase-variable type I restriction-modification (R-M) systems are part of the core genome. We hypothesized that the ability of the R-M systems to switch between six target DNA specificities also has a key role in preventing the spread of bacteriophages. Using the streptococcal temperate bacteriophage SpSL1, we show that the variants of both the SpnIII and SpnIV R-M systems are able to restrict invading bacteriophage with an efficiency approximately proportional to the number of target sites in the bacteriophage genome. In addition to restriction of lytic replication, SpnIII also led to abortive infection in the majority of host cells. During lytic infection, transcriptional analysis found evidence of phagehost interaction through the strong upregulation of the nrdR nucleotide biosynthesis regulon. During lysogeny, the phage had less of an effect on host gene regulation. This research demonstrates a novel combined bacteriophage restriction and abortive infection mechanism, highlighting the importance that the phase-variable type I R-M systems have in the multifunctional defense against bacteriophage infection in the respiratory pathogen S. pneumoniae.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.