A flagella-dependent jumbo phage controls rice seedling rot and steers toward reduced virulence in rice seedlings.

Bacteriophages (phages) are being investigated as potential biocontrol agents for the suppression of bacterial diseases in cultivated crops. Jumbo bacteriophages, which possess genomic DNA larger than 200 kbp, generally have a broader host range than other phages and therefore would be useful as biocontrol agents against a wide range of bacterial strains. Thus, the characterization of novel jumbo phages specific for agricultural pathogens would be of importance for the development of phage biocontrol strategies. Herein, we demonstrate that phage S13 requires flagella for its attachment and infection and that loss of flagella prevents S13 cellular lysis. As flagella is a known virulence factor, loss of flagella results in a surviving population of with reduced virulence. Further experimentation demonstrates that phage S13 can protect rice plants from -sponsored destruction in a rice seedling model of infection.IMPORTANCEBacterial plant pathogens threaten many major food crops and inflict large agricultural losses worldwide. is a bacterial plant pathogen that causes diseases such as rot, wilt, and blight in several food major crops including rice, tomato, hot pepper, and eggplant. infects rice during all developmental stages, causing diseases such as rice seedling rot and bacterial panicle blight (BPB). The incidence of rice plant infection is predicted to increase with warming global temperatures, and several different control strategies targeting are being explored. These include chemical and antibiotic soil amendment, microbiome manipulation, and the use of partially resistant rice cultivars. However, despite rice growth amelioration, the treatment options for plant infections remain limited to cultural practices. Alternatively, phage biocontrol represents a promising new method for eliminating from crop soils and improving rice yields.