ERWINIA SPECIES IDENTIFICATION USING MATRIX-ASSISTED LASER DESORPTION IONIZATION-TIME OF FLIGHT MASS SPECTROMETRY

Rapid and reliable identification of plant pathogenic bacteria is critical for effective implementation of phytosanitary measures. The genus Erwinia includes a number of economically important plant pathogens such as fire blight agent Erwinia amylovora or Asian pear pathogen Erwinia pyrifoliae, together with closely related plant epiphytes of unknown pathogenicity or even with a potential use for biological control like Erwinia tasmaniensis or Erwinia billingiae, respectively. Current laboratory methods to achieve satisfactory identification and discrimination between species within the Erwinia genus are based on the isolation on semi-selective media, serology, specific PCR and gene locus sequencing: these approaches are complicated and time-consuming, often requiring a priori assumptions over the identity of the isolates. Here we present a streamlined approach based on whole-cell Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) based on the AXIMA mass spectrometer of Shimadzu-Biotech Corp that demonstrates the potential of this technology for quick species identification in plant diagnostics within the genus Erwinia.