Volatile fingerprint by SPME-GC-FID to discriminate olive tree varieties infected by Xylella fastidiosa. Volatile fingerprint to discriminate olive tree varieties infected by Xylella fastidiosa

The presence of Xylella fastidiosa subsp. pauca in olive samples was assesed by PCR employing different pairs of species-specific primers: XF1/6, S-S-X.fas-0067-a-S-19/S-S-X.fas-0038-a-A-21, FXYgyr499/RXYgyr907 and HL5/6. A headspace solid phase microextraction (HS-SPME) method combined with gas chromatography-mass spectrometry (GC/MS) was developed and optimized for extraction and analysis of volatile organic compounds (VOCs) of healthy and Xylella fastidiosa (Xf) subsp. pauca infected olive trees. More than hundred compounds were identified in the analyzed samples including acids, esters, alcohols, methyl esters, other esters, aldehydes, hydrocarbons, terpene derivates, furanes and ketones. Moreover, in the infected twigs a lower content of carbonylic compounds (ketones and aldehydes) and a higher content of hydrocarbons were been verified indicating new metabolic pathway produced by the interaction host/plant.