Isolation and Characterization of a Lytic Bacteriophage RH-42-1 of Erwinia amylovora from Orchard Soil in China

• Published in: Viruses Vol. 16; no. 4; p. 509
• Main Authors: Xi, Haishen, Fu, Benzhong, Sheng, Qiang, Luo, Ming, Sun, Liying
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 26.03.2024; MDPI
• Subjects: Alphatectivirus; Antibiotics; Bacteria; Bacterial infections; bacteriophage; Bacteriophages - classification; Bacteriophages - genetics; Bacteriophages - isolation & purification; Bacteriophages - physiology; Blight; Burst size; Cell size; China; Chloroform; Disease; Electron microscopy; Erwinia amylovora; Erwinia amylovora - drug effects; Erwinia amylovora - virology; fire blight; genome; Genome, Viral; Genomes; Host range; Host Specificity; Hydrogen peroxide; Hydrogen-Ion Concentration; Infectivity; Latent period; Morphology; Multiplicity of infection; Pathogens; Phages; Phylogeny; Plant Diseases - microbiology; Pyrus - microbiology; Pyrus - virology; resistance; Soil Microbiology; Ultraviolet radiation; China; United States > US; genome; RH-42-1; fire blight; Alphatectivirus; orchard soil; Erwinia amylovora; bacteriophage; resistance
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v16040509

Fire blight, caused by the bacterium , is a major threat to pear production worldwide. Bacteriophages, viruses that infect bacteria, are a promising alternative to antibiotics for controlling fire blight. In this study, we isolated a novel bacteriophage, RH-42-1, from Xinjiang, China. We characterized its biological properties, including host range, plaque morphology, infection dynamics, stability, and sensitivity to various chemicals. RH-42-1 infected several strains but not all. It produced clear, uniform plaques and exhibited optimal infectivity at a multiplicity of infection (MOI) of 1, reaching a high titer of 9.6 × 10 plaque-forming units (PFU)/mL. The bacteriophage had a short latent period (10 min), a burst size of 207 PFU/cell, and followed a sigmoidal one-step growth curve. It was stable at temperatures up to 60 °C but declined rapidly at higher temperatures. RH-42-1 remained viable within a pH range of 5 to 9 and was sensitive to extreme pH values. The bacteriophage demonstrates sustained activity upon exposure to ultraviolet radiation for 60 min, albeit with a marginal reduction. In our assays, it exhibited a certain level of resistance to 5% chloroform (CHCl ), 5% isopropanol (C H O), and 3% hydrogen peroxide (H O ), which had little effect on its activity, whereas it showed sensitivity to 75% ethanol (C H OH). Electron microscopy revealed that RH-42-1 has a tadpole-shaped morphology. Its genome size is 14,942 bp with a GC content of 48.19%. Based on these characteristics, RH-42-1 was identified as a member of the family, genus. This is the first report of a bacteriophage in this genus with activity against .