Lysogenic Conversion of the Phytopathogen Ralstonia solanacearum by the P2virus ?RSY1.

ABSTRACT: A P2-like phage ?RSY1 infecting the phytopathogen Ralstonia solanacearum was isolated and characterized. The 40-kb genome of ?RSY1 showed high sequence similarity to the Ralstonia phage ?RSA1 and the GMI1000 prophage ?RSX. The major genomic differences between these phages were the different orientation of the int gene and the gene content close to the cosL. ?RSY1 and ?RSX use a 15-base 3' portion of the serine tRNA(GGA) gene as attB, while ?RSA1 uses a 45-base 3' portion of the arginine tRNA(CCG) gene. The different orientation of int in the genomes means that the gene arrangements in the prophage states are reversed in ?RSY1 and ?RSA1. Several putative gene products of ?RSY1 may affect the bacterium's fitness. ?RSY1 contains an open reading frame (ORF) that seems to encode a protein similar to Vgr in the type VI secretion system of various bacterial species. ?RSY1 lysogens showed phenotypic changes including enhanced twitching motility, large colony formation, and easy aggregation of cells, suggesting involvement of this ORF in the changes. In view of these phage gene arrangements, we surveyed prophages in the genomes of various R. solanacearum strains and found that the P2-like phages of R. solanacearum (14 phages) consist of two major groups: the ?RSY1-type and the ?RSA1-type. The relationships and evolution of these P2-like phages inferred from our data are discussed in detail.

SUBMITTER: Askora A 

PROVIDER: S-EPMC5694545 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature