Green approach to phytopathogen: Characterization of lytic bacteriophages of Pseudomonas sp., an etiology of the bacterial blight of pomegranate.

Two morphologically different bacteriophages were isolated from the river and soil samples from various locations of Maharashtra, India against the phytopathogen Pseudomonas sp. that was recently reported to cause a new bacterial blight of pomegranate. Both the phages belonged to the order Caudovirales representing the families Siphoviridae (vB_Psp.S_PRɸL2) and Myoviridae (vB_Psp.M_SSɸL8). The multiplicity of infection ranged from 0.01 to 0.1, phage adsorption rate from 39% to 66%, latent period from 10 to 20 min with a burst size of 24-85 phage particles per infected host cell. The genome size of phages PRɸL2 and SSɸL8 was approximately 25.403 kb and 29.877 kb respectively. Restriction digestion pattern of phage genomic DNA was carried out for phage PRɸL2, Eco RI resulted in two bands and Hind III resulted in three bands while for phage SSɸL8, both Eco RI and Hind III each resulted in three bands. SDS-PAGE protein profile showed six bands for PRɸL2 and nine bands for SSɸL8 of different proteins. Phages showed high pH stability over a range of 4-9, temperature stability over a range of 4-50 °C and UV radiation showed a reduction up to 89.36% for PRɸL2 and 96% for SSɸL8. In short, the present research work discusses for the first time in-detailed characterization of phages of a phytopathogen Pseudomonas sp. from Maharashtra, India, which can be further efficiently used for biological control of the causative agent of a new bacterial blight disease of pomegranate.

BVPaP-3, a T7-like lytic phage of Pseudomonas aeruginosa: its isolation and characterisation.

The increasing emergence of antibiotic-resistant bacteria has produced a growing interest among scientists in bacteriophages as alternative antimicrobial agents. This article reports a lytic phage against an antibiotic-resistant strain of Pseudomonas aeruginosa. Phage BVPaP-3 is a member of the Podoviridae family and morphologically similar to the T7-like phage gh-1. The phage has a hexagonal head of 58-59 nm in diameter and a short tail of 10 × 8 nm. It is stable at a wide range of pH (6-10) and temperatures (4-40°C). Its optimal growth temperature is 37°C and the adsorption rate constant is 1.19 × 10(-9). Latent and eclipse periods are 20 and 15 min, respectively, and the burst size is 44 after 35 min at 37°C. The phage has a DNA size of 41.31 kb and a proteome of 11 proteins. The major protein is 33 kDa in size.