Protection ofErwinia amylovorabacteriophage Y2 from UV-induced damage by natural compounds

Abstract

Bacteriophages have regained much attention as biocontrol agents against bacterial pathogens. However, with respect to stability, phages are biomolecules and are therefore sensitive to a number of environmental influences. UV-irradiation can readily inactivate phage infectivity, which impedes their potential application in the plant phyllosphere. Therefore, phages for control of , the causative agent of fire blight, need to be protected from UV-damage by adequate measures. We investigated the protective effect of different light-absorbing substances on phage particles exposed to UV-light. For this, natural extracts from carrot, red pepper, and beetroot, casein and soy peptone in solution, and purified substances such as astaxanthin, aromatic amino acids, and Tween 80 were prepared and tested as natural sunscreens for phage. All compounds were found to significantly increase half-life of UV-irradiated phage particles and they did not negatively affect phage viability or infectivity. Altogether, a range of readily available, natural substances are suitable as UV-protectants to prevent phage particles from UV-light damage.

DNA preservation in silk

“…Thus the assumption is that some degree of hydrophobic interaction may play a role, or some degree of pi-pi stacking with the predominant tyrosines present in the silk (~5% from gene sequence prediction and amino acid residue analysis) 41, 42 . As reported in the literature, aromatic amino acids including tyrosine could protect bacteriophage Y2 from inactivation by UV-light 43 . The abundant and inexpensive silk material obtained via the textile industry via sericulture, the simple and all-aqueous process used here, and the diversified material formats available with silk materials provide an alternative for DNA preservation in a variety of applications.…”

Bacteriophages and Bacterial Plant Diseases

“…Born et al (2015) conducted studies with number of substances to investigate if they gave phage protection against UV and reported that natural extracts from carrot, red pepper and beetroot all gave protection as did casein, soy peptone and also purfied aromatic amino acids, astaxathin and Tween 80. None of these subtances had a compromising effect on phage infection and stability (Born et al, 2015).…”

“…None of these subtances had a compromising effect on phage infection and stability (Born et al, 2015). Thus, it appears that a wide range of substances could enhance phage preformance in the phyllosphere with the main requirement being that they need to absorb UV thus limiting phage exposure.…”

“…vesicatoria , preventing it from exerting a biocontrol effect. Phage sensitivity against UV light has been shown to occur also with phage of Dickya solani and E. amylovora phages (Czajkowski et al, 2014; Born et al, 2015). However, there have been phages isolated against the phytopathogen Pseudomonas syringae pv.…”

Biocontrol of phytobacteria with bacteriophage cocktails

“…Phages may also be supplemented with light‐absorbing substances. One study explored the use of natural compounds to minimize the ultraviolet (UV)‐induced damage of Erwinia amylovora phage Y2 . When supplemented with 10% carrot or 5% red pepper juice, 28% and 34% respectively of the initial phage titer survived after 5 min exposure to UV irradiation.…”