Plants release a large number of volatile molecules (including ethylene, terpenoids, lipoxygenase-derived volatiles) and the emission profiles change after damaging. Several studies have demonstrated that semiochemicals play an important role in plant defence against biotic stresses, for example, some plants may emit molecules when attacked by herbivores to attract their natural enemies. Moreover, exogenous application of these molecules can induce a subset of defence responses against fungal and bacterial pathogens. In order to evaluate the role of semiochemicals in tobacco (Nicotiana tabacum cv Havana 425) resistance against Erysiphe cichoracearum (causal agent of powdery mildew), analyses were conducted to identify and quantify the emission of volatile compounds in uninfected and infected plants. Plants were analysed at different time intervals after infection done by spraying an aqueous suspension containing 105 fresh conidia/ml. Volatile compounds emitted from plants were collected by headspace- solid phase micro extraction (HS-SPME) and analysed by gas chromatography (GC-FID) and gas chromatography–mass spectrometry (GC-MS). Significant differences in the emission of volatile compounds by infected plants were observed with time with respect to uninfected control. An increase in terpenoids (E-beta- ocimene and Z-beta-ocimene) was observed 24h after infection, whereas cis-jasmone and methyl-jasmonate showed highest concentrations at 48 and 72h after infection, respectively. The volatile compounds reported above will be further tested for their ability to induce resistance in tobacco against powdery mildew.
Tobacco-Erysiphe cichoracearum: a possible role of plant semiochemicals in induced resistance
QUAGLIA, Mara;ZADRA, Claudia;FABRIZI, MARIO;VOLPE, Daniela;ZAZZERINI, Antonio
2007
Abstract
Plants release a large number of volatile molecules (including ethylene, terpenoids, lipoxygenase-derived volatiles) and the emission profiles change after damaging. Several studies have demonstrated that semiochemicals play an important role in plant defence against biotic stresses, for example, some plants may emit molecules when attacked by herbivores to attract their natural enemies. Moreover, exogenous application of these molecules can induce a subset of defence responses against fungal and bacterial pathogens. In order to evaluate the role of semiochemicals in tobacco (Nicotiana tabacum cv Havana 425) resistance against Erysiphe cichoracearum (causal agent of powdery mildew), analyses were conducted to identify and quantify the emission of volatile compounds in uninfected and infected plants. Plants were analysed at different time intervals after infection done by spraying an aqueous suspension containing 105 fresh conidia/ml. Volatile compounds emitted from plants were collected by headspace- solid phase micro extraction (HS-SPME) and analysed by gas chromatography (GC-FID) and gas chromatography–mass spectrometry (GC-MS). Significant differences in the emission of volatile compounds by infected plants were observed with time with respect to uninfected control. An increase in terpenoids (E-beta- ocimene and Z-beta-ocimene) was observed 24h after infection, whereas cis-jasmone and methyl-jasmonate showed highest concentrations at 48 and 72h after infection, respectively. The volatile compounds reported above will be further tested for their ability to induce resistance in tobacco against powdery mildew.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
