2 research outputs found
Volatolomics approach by HSâSPMEâGCâMS and multivariate analysis to discriminate olive tree varieties infected by Xylella fastidiosa
Introduction: Xylella fastidiosa (Xf) is a pathogenic bacterium that causes diseases in
olive trees. Therefore, analytical methods for both the characterisation of the
host/pathogen interaction and infection monitoring are needed. Volatile organic compounds
(VOCs) are emitted by plants relate to their physiological state, therefore
VOCs monitoring can assist in detecting stress or infection states before visible signs
are present.
Objective: In this work, the headspaceâsolid phase microextractiongaschromatographyâ
mass spectrometry (HSâSPMEâGCâMS) technique was used for
the first time to highlight VOCs differences between healthy and Xfâinfected olive
trees.
Methodology: VOCs from olive tree twig samples were extracted and analysed by
HSâSPMEâGCâMS, and hence identified by comparing the experimental linear retention
indexes with the reference values and by MS data obtained from NIST library.
Data were processed by principal component analysis (PCA) and analysis of variance
(ANOVA).
Results: The HSâSPME step was optimised in terms of adsorbent phase and extraction
time. HSâSPMEâGCâMS technique was applied to the extraction and analysis of
VOCs of healthy and Xfâinfected olive trees. More than 100 compounds were identified
and the differences between samples were evidenced by the multivariate
analysis approach. The results showed the marked presence of methyl esters in Xfinfected
samples, suggesting their probable involvement in the mechanism of diffusible
signal factor.
Conclusion: The proposed approach represents an easy and solventâfree method to
evaluate the presence of Xf in olive trees, and to evidence volatiles produced by
host/pathogen interactions that could be involved in the defensive mechanism of
the olive tree and/or in the infective action of Xf