Characterization and classification of a novel bacteriophage, vB_RsoP_HXg1W, infecting Ralstonia pseudosolanacearum: a new member of the genus Serkorvirus in the family Autotranscriptaviridae.

Abstract

Bacterial wilt caused by Ralstonia solanacearum species complex (RSSC) is a significant threat to agriculture due to the pathogen's broad host range and persistence in soil. Bacteriophages (phages) are being explored as biocontrol agents, and such strategies are gaining interest. In this study, we isolated and characterized vB_RsoP_HXg1W, a novel phage propagated on R. pseudosolanacearum GMI1000. The phage has a linear double-stranded DNA genome of 40,184 bp with a GC content of 62.3%, and displays an icosahedral head with a short tail. A total of 51 open reading frames (ORFs) were identified, and no tRNA genes were detected. Comparative genomic and phylogenetic analyses revealed that vB_RsoP_HXg1W is closely related to Ralstonia phage p2137, p2106, and RpY2, and clusters within the genus Serkorvirus in the family Autotranscriptaviridae. VIRIDIC analysis revealed a maximum intergenomic similarity of 84.7% to the closest included relative, supporting vB_RsoP_HXg1W as a putative novel species-level member of Serkorvirus. These findings contribute to the understanding of RSSC-infecting phages and provide a foundation for further exploration of phage evolution, host range, and biocontrol relevant traits.