ARS | Publication request: “Light-tagged” bacteriophage as a diagnostic tool for the detection of phytopathogens

Submitted to: Bioengineered Bugs
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 10, 2012
Publication Date: N/A

Interpretive Summary: Bacterial diseases of plants result in the loss of harvestable crops thus limiting the availability of those crops to consumers. Disease control and prevention is dependent upon understanding what pathogens cause disease and the mode by which the pathogen comes in contact with the crop. However microorganisms are small and it is difficult to determine whether they are present in the environment or on plants. This manuscript describes a new method that can rapidly indicate if a plant pathogen is present in levels high enough to cause disease. Furthermore, data generated using these tools will allow researchers to design preventative disease control strategies. The control of bacterial plant pathogens is fundamental to providing high quality food and fiber to consumers.

Technical Abstract: Detection of the phytopathogen Pseudomonas cannabina pv. alisalensis, the causeal agent of bacterial blight of crucifers is essential for managing this disease. A phage-based diagnostic assay was developed that detected and identify P. cannabina pv. alisalensis from cultures and diseased plant specimens. A recombinant “light-tagged” reporter phage was generated by integrating the luxAB genes into the genome of the P. cannabina pv. alisalensis phage PBSPCA1. The PBSPCA1::luxAB reporter phage was viable, stable and able to detect P. cannabina pv. alisalensis by rapidly (within minutes) and sensitively (103 CFU/mL) conferring a bioluminescent signal response to cultured cells. Detection was dependent on cell viability since ethanol-treated cells, which reduced viability 106-fold, were unable to elicit a signal response. Importantly, the reporter phage was able to detect P. cannabina pv. alisalensis from diseased plant specimens indicating the potential of the diagnostic for disease identification. The reporter phage displays promise for the rapid and specific diagnostic detection of cultivated isolates, and infected plant specimens.