Isolation and Characterization of Bacteriophages Infecting , the Major Causal Agent of Bacterial Panicle Blight in Rice.

Bacterial panicle blight (BPB), caused by , is one of the most severe seed-borne bacterial diseases of rice in the world, which can decrease rice production by ≤75%. Nevertheless, there are few effective measures to manage this disease. In an attempt to develop an alternative management tool for BPB, we isolated and characterized phages from soil and water that are effective to lyse several strains of After tests of host ranges, the phages NBP1-1, NBP4-7, and NBP4-8 were selected for further comprehensive characterization, all of which could lyse BGLa14-8 (phage sensitive) but not 336gr-1 (phage insensitive). This result indicates that the phages killing cells have specific host ranges at the strain level within the bacterial species. In the greenhouse condition of this study, foliar application of the phage NBP4-7 reduced the severity of BPB caused by BGLa14-8 ≤62% but did not cause any significant effect on the infection by 336gr-1. Electron microscopy and whole-genome sequencing were also performed to characterize the three selected phages. Transmission electron microscopy revealed that the selected phages belong to the family Myoviridae. Furthermore, whole-genome sequence analysis indicated that the three phages belong to a same species and are closely related to the , a member of the Myoviridae family.