Novel Lytic Agrobacterium Bacteriophage Miki Representing a New Genus

Abstract

Rhizogenic Agrobacterium (Rhizobium) spp. are causative agents of hairy root disease (HRD), a major threat to hydroponic crop production worldwide. The use of specific bacteriophages is considered a prospective approach to control the development of HRD in greenhouses. A combination of diverse bacteriophages is a key step to overcome potential phage resistance in the pathogen. In this study, a novel lytic bacteriophage, named Miki, was identified and characterized for its antibacterial potential against a rhizogenic Agrobacterium sp. strain circulating in greenhouses in Central Russia. High-throughput sequencing revealed a 63,458 bp double-stranded DNA genome (G + C content 53%), with 117 predicted coding sequences, considering Miki as a lytic candidate phage for plant protection. Electron microscopy of phage Miki shows a morphology unusual for Agrobacterium phages, and phylogenetic analysis attributes it as a representative of a previously undescribed taxon at least at the genus level. The paper presents a detailed analysis of the genome and structural proteome of phage Miki, including in silico predictions and modeling of receptor-binding proteins, including central and proximal fibers resembling the adsorption apparatus of Escherichia phage T5.