Identification and detection of wheat pathogens through volatile organic compound analysis
A. FICKE (1), B. Asalf (1), H. R. Norli (1), G. K. Knudsen (1). (1) Bioforsk Plant Health, Ås, Norway
Research shows that fungi produce different VOCs in different concentrations depending on their species, developmental stage, and abiotic and biotic factors. The objective of this work was to detect and distinguish fungal wheat pathogens by VOC profile analysis. Single spore isolates from <i>Fusarium graminearum</i>, <i>F. culmorum</i>, <i>F. poa</i>, <i>F. avenaceum</i>, <i>Phaeosphaeria nodorum</i>, <i>Mycosphaerella graminicola</i>, and <i>Pyrenophora tritici-repentis</i> were grown 7 days in 5cm-PDA petri dishes. In parallel experiments, wheat plants were inoculated with <i>B. graminis</i>, <i>F. graminearum</i>, and <i>P. nodorum</i> and sampled 7, 14 and 21 days post inoculation dpi. We collected VOCs using a Super Q filter fitted on airtight glass containers, eluted with hexane, and injected the extract into the GC/MS. The GC data sets were analyzed, aligned and compared using MetAlignTM. VOC collection of each isolate and each wheat-pathogen combination was repeated 3-5 times. In contrast to the controls, <i>P. nodorum</i> isolates produced Mellein, <i>M. graminicola</i> produced 6-methyl-5-hepten-2-one, Isosativene, 2-one, and Mellein, while <i>F. poa</i> produced 1,2,3-trimethylbenzen and Sesquiterpen, possibly Germacrende D. Powdery mildew, leaf blotch and Fusarium head blight produced clearly distinguishable VOC profiles. We will discuss the application of these findings in early detection of plant diseases and in site specific disease control.
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