Host Range for Bacteriophages that Infect Bacterial Blight Pathogen on Soybean

Bacterial blight disease caused by Pseudomonas syringae pv. glycinea becomes one among several important factors that affects soybean production. To control this pathogen, most farmers apply synthetic pesticides that have negative effect for human, animal, and environment. Therefore, an alternative control must be developed including the use of bacteriophages. Moreover, identification and detection of this pathogen should be accurate for optimal diseases management. On the other hand, bacteriophage, a virus that infects specific host-bacterium, is largely known to have the ability to kill their specific host- bacterium. In addition, bacteriophage is also used as diagnostic tool for bacterial detection and identification of purpose, known as phatovar classification. This research was aimed to isolate the bacterial blight pathogen and their bacteriophage from soybean field in Jember, determine the pathogen pathogenicity and virulence, and determine the host-range of bacteriophage that infects several isolates of bacterial blight pathogen on soybean. The results has shown that among 12 isolates of bacterial blight pathogens that had similar characteristic to P. syringae pv. glycinea, only 10 isolates showed positive hypersensitive response (HR) on tobacco leaf. However, all isolates were virulent when inoculated to soybean leaves by showing particular bacterial blight symptom. In addition, one bacteriophage was found to infect isolate H3, called ϕPSGH3, and was to have 6 hosts among 12 bacterial isolates including isolates H3, SK4-2, BT4-1, KR1-1, KR4-2 dan MG4-1. The results from plaque assay PSGH3 with ϕH3-1 found out three only particle bacteriophage which are ϕGH1, ϕGH2 and ϕGH3.