Isolation of the Novel Phage PHB09 and Its Potential Use against the Plant Pathogen Pseudomonas syringae pv. actinidiae

Abstract

Bacteriophages are viruses that specifically infect target bacteria. Recently, bacteriophages have been considered potential biological control agents for bacterial pathogens due to their host specificity. Pseudomonas syringae pv. actinidiae (Psa) is a reemerging pathogen that causes bacterial canker of kiwifruit (Actinidia sp.). The economic impact of this pest and the development of resistance to antibiotics and copper sprays in Psa and other pathovars have led to investigation of alternative management strategies. Phage therapy may be a useful alternative to conventional treatments for controlling Psa infections. Although the efficacy of bacteriophage φ6 was evaluated for the control of Psa, the characteristics of other DNA bacteriophages infecting Psa remain unclear. In this study, the PHB09 lytic bacteriophage specific to Psa was isolated from kiwifruit orchard soil. Extensive host range testing using Psa isolated from kiwifruit orchards and other Pseudomonas strains showed PHB09 has a narrow host range. It remained stable over a wide range of temperatures (4–50 °C) and pH values (pH 3–11) and maintained stability for 50 min under ultraviolet irradiation. Complete genome sequence analysis indicated PHB09 might belong to a new myovirus genus in Caudoviricetes. Its genome contains a total of 94,844 bp and 186 predicted genes associated with phage structure, packaging, host lysis, DNA manipulation, transcription, and additional functions. The isolation and identification of PHB09 enrich the research on Pseudomonas phages and provide a promising biocontrol agent against kiwifruit bacterial canker.

Biological characteristics of the bacteriophage LDT325 and its potential application against the plant pathogen Pseudomonas syringae

“…In addition, pH significantly influenced adsorption, contagiousness, intracellular multiplication, and enhancement of the bacteriophage. Unfavorable pH values can disrupt lysozyme or other phage capsid proteins, ultimately hindering phage attachment to receptor sites on the host cell ( Liu et al, 2021 ). Bacteriophage LDT325 was highly active at pH 3–11 but could not be detected at pH 1–2 and pH 13.…”

“…The latent period and outbreak size of the isolated bacteriophage were 10 and 150 min, respectively. The latent period of phage LDT325 was shorter than that of phage PHB09, which is also specific to P. syringae ( Liu et al, 2021 ). Therefore, phage LDT325 is more conducive to practical application.…”

“…In vitro , 48 h of phage therapy markedly diminished the bacterial load compared with untreated cultures. In in vitro experiments, compared with phage PHB09, phage LDT325 showed a significant antibacterial effect ( Liu et al, 2021 ). For the effective application of phages in controlling bacteria that cause plant diseases, the bacteriophage must interact with the host on the leaf surface ( Vieira et al, 2012 ).…”

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

“…The spot method was used to determine the bacteriophage host range [ 19 ]. Fourteen strains of E. amylovora , one strain of E. coli , one strain of P. syringae pv.…”

Isolation of Novel Xanthomonas Phages Infecting the Plant Pathogens X. translucens and X. campestris

“…Erwinia amylovora , which developed resistance to streptomycin, has led to the evaluation of phage biocontrol with promising outcomes in some cases [ 14 , 15 , 16 ]. Due to the broad spectrum of plants infected by Pseudomonas syringae spp., multiple biocontrol trails have been conducted in the past, but with a special effort on citrus canker disease [ 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. Xylella fastidiosa is a major threat to olive trees in Europe, where first phages have been isolated and tested [ 24 , 25 , 26 ].…”