Volatile compounds produced by Erwinia amylovora and their potential exploitation for bacterial identification

Since volatile production reflects the specific metabolism of individual microorganisms, profiling the volatile emission was used for the identification of plant pathogenic and plant associated bacteria. A first characterization of the volatile profiles of the different bacterial species was obtained by proton transfer reaction-mass spectrometry which allows the real-time monitoring of the emission. Successively, the gas chromatographic-mass spectroscopy analysis was used for identifying the specific volatiles emitted by each of the bacterial species. Finally, electronic nose instrumentation was challenged discriminating Erwinia amylovora from the other bacteria frequently isolated from the phylloplane. The electronic nose identification by direct comparison of the odorous profiles of unknown bacterial isolates with reference species allowed a correct classification in 87% of the cases. These promising results show that the electronic nose can be potentially used as a screening method to support the bacterial identification. However, methods to enhance the stability and reliability of the electronic nose measures need to be developed. In addition, the characterization of the volatiles which primarily contribute to the odorous profiles of the different plant pathogenic bacteria may allow the development of reliable and highly sensitive electronic nose sensors.