Replications of Two Closely Related Groups of Jumbo Phages Show Different Level of Dependence on Host-encoded RNA Polymerase.

ABSTRACT: Ralstonia solanacearum phages ?RP12 and ?RP31 are jumbo phages isolated in Thailand. Here we show that they exhibit similar virion morphology, genome organization and host range. Genome comparisons as well as phylogenetic and proteomic tree analyses support that they belong to the group of ?KZ-related phages, with their closest relatives being R. solanacearum phages ?RSL2 and ?RSF1. Compared with ?RSL2 and ?RSF1, ?RP12 and ?RP31 possess larger genomes (ca. 280 kbp, 25% larger). The replication of ?RP12 and ?RP31 was not affected by rifampicin treatment (20 ?g/ml), suggesting that phage-encoded RNAPs function to start and complete the infection cycle of these phages without the need of host-encoded RNAPs. In contrast, ?RSL2 and ?RSF1, encoding the same set of RNAPs, did not produce progeny phages in the presence of rifampicin (5 ?g/ml). This observation opens the possibility that some ?RP12/?RP31 factors that are absent in ?RSL2 and ?RSF1 are involved in their host-independent transcription.

SUBMITTER: Matsui T 

PROVIDER: S-EPMC5468394 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature