초록
<P>Volatile organic compounds (VOCs) are responsible for the antagonistic activity exerted by different biological control agents (BCAs). In this study, VOCs produced by <I>Pseudomonas synxantha</I> strain 117-2b were tested against two kiwifruit fungal postharvest pathogens: <I>Cadophora luteo-olivacea</I> and <I>Botrytis cinerea</I>, through <I>in vitro</I> and <I>in vivo</I> assays. <I>In vitro</I> results demonstrated that <I>P. synxantha</I> 117-2b VOCs inhibit mycelial growth of <I>C. luteo-olivacea</I> and <I>B. cinerea</I> by 56% and 42.8% after 14 and 5 days of exposition, respectively. <I>In vivo</I> assay demonstrated significant inhibitory effects. VOCs used as a biofumigant treatment reduced skin-pitting symptoms disease severity by 28.5% and gray mold incidence by 66.6%, with respect to the untreated control. BCA volatiles were analyzed by solid-phase microextraction coupled with gas chromatography-mass spectrometry (SPME-GC/MS), and among the detected compounds, 1-butanol, 3-methyl and 1-nonene resulted as the most produced. Their efficacy as pure synthetic compounds was assayed against mycelial growth of fungal pathogens by different concentrations (0.34, 0.56, and 1.12 µL mL<SUP>−1</SUP> headspace). The effect of the application of VOCs as a biofumigant was also investigated as the expression level of seven defense-related genes of kiwifruit at different exposition times. The results indicated an enhancement of the expression of almost all the genes starting from 3 h of treatment. These results described <I>P. synxantha VOCs</I> characteristics and their potential as a promising method to adopt for protecting kiwifruit from postharvest diseases caused by <I>C. luteo-olivacea</I> and <I>B. cinerea</I>.</P>