Pantoea ananatis is an emerging phytopathogen that causes leaf blight and fruit or bulb rot diseases in a wide range of economically important plant species, resulting in severe yield loss. This study investigates the isolation and characterization of a virulent bacteriophage for potential biocontrol of bacterial rot and leaf blight diseases caused by P. ananatis.

Results
Virulent phage was isolated from surface agricultural drainage water collected in Dakahlia Governorate, Egypt using a single plaque purification method. Morphological analysis classified phage PanM1EGY as Myovirus-like. The optimal multiplicity of infection (MOI) was 0.1; one step growth curve revealed a latency period of 30 min and a burst size of approximately 252 ± 2 PFU/ cell. Environmental stability tests showed that phage PanM1EGY maintained activity across a broader temperature range (4 °C–70 °C) and under pH conditions ranging from 5 to 11. Results of the UV and NaCl tolerance experiments showed that the phage titer did not change following 5 min of UV exposure or incubation at a 5% NaCl concentration. In vitro assay indicated that the phage effectively reduced and prevented P. ananatis growth. The genome of PanM1EGY consisted of a double-stranded DNA with a total length of 77,516 base pairs and a GC content of 37%. A total of 131 coding sequences were predicted. In planta experiments utilizing phage treatments demonstrated that treated potato tubers, onion bulbs, and garlic cloves exhibited inhibition of rot disease symptoms compared to untreated controls. Likewise, the phage treatment effectively prevented the development of leaf blight in strawberry leaves.

Conclusion
These results highlight the possibility of using P. ananatis-infecting phage as a sustainable biocontrol method to manage the symptoms of the disease induced by rot and leaf blight across variety of plants.