Lysogenic Conversion of the Phytopathogen by the P2virus ϕRSY1.

A P2-like phage ϕRSY1 infecting the phytopathogen was isolated and characterized. The 40-kb genome of ϕRSY1 showed high sequence similarity to the phage ϕRSA1 and the GMI1000 prophage ϕRSX. The major genomic differences between these phages were the different orientation of the gene and the gene content close to the L. ϕRSY1 and ϕRSX use a 15-base 3' portion of the serine tRNA(GGA) gene as B, while ϕRSA1 uses a 45-base 3' portion of the arginine tRNA(CCG) gene. The different orientation of in the genomes means that the gene arrangements in the prophage states are reversed in ϕRSY1 and ϕRSA1. Several putative gene products of ϕRSY1 may affect the bacterium's fitness. ϕRSY1 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. ϕRSY1 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 strains and found that the P2-like phages of (14 phages) consist of two major groups: the ϕRSY1-type and the ϕRSA1-type. The relationships and evolution of these P2-like phages inferred from our data are discussed in detail.