Stress factors can alter the blend of volatile organic compounds (VOCs) released by plants, inducing an higher amounts of phyto -chemicals synthesizedde novoor emitted. These novel compounds are referred as induced VOCs (IVOCs). We previously reported that Golovinomyces cichoracearum , a powdery mildew agent, induced an increased emission of methyl-jasmonate (MeJA), (E)-2-hexenal and (E)-β-ocimene in the susceptible Nicotiana tabacum cv. Havana 425. We have now tested these compounds for their ability to protect tobacco from G. cichoracearum and for accumulation of lipoxygenase (LOX), allene oxide cyclase (AOC) and defensin genes transcripts, markers of JA-defence pathway. MeJA 2 mM and (E)-2-hexenal 5 mM reduced the disease severity, compared to the control. Protection conferred by MeJA could be due to the activation of the JA-defence pathway, as it induced in tobacco the accumulation of LOX, AOC and defensin genes transcripts and did not inhibit fungal germ tube growth. Protection conferred by (E)-2-hexenal could be mainly attributable to its antimicrobial activity, as it did not induce the accumulation of genes transcripts but inhibited fungal germ tube growth. The increased disease severity caused by ( E)-β-ocimene 0.18 mM could be due to the in vitro stimulation of conidial germination. At the above tested concentrations, the three compounds significantly reduced Myzus persicae infestation with respect to the control. Thus, the defence responses induced by the pathogen were able to protect the plant also from aphid attacks emphasizing the importance of studying plant responses also in a multitrophic in teraction system
Effect of pathogen induced volatile organic compounds on powdery mildew infection, aphid infestation and on genes induction in tobacco.
QUAGLIA, Mara;FABRIZI, MARIO;ZAZZERINI, Antonio;ZADRA, Claudia
2013
Abstract
Stress factors can alter the blend of volatile organic compounds (VOCs) released by plants, inducing an higher amounts of phyto -chemicals synthesizedde novoor emitted. These novel compounds are referred as induced VOCs (IVOCs). We previously reported that Golovinomyces cichoracearum , a powdery mildew agent, induced an increased emission of methyl-jasmonate (MeJA), (E)-2-hexenal and (E)-β-ocimene in the susceptible Nicotiana tabacum cv. Havana 425. We have now tested these compounds for their ability to protect tobacco from G. cichoracearum and for accumulation of lipoxygenase (LOX), allene oxide cyclase (AOC) and defensin genes transcripts, markers of JA-defence pathway. MeJA 2 mM and (E)-2-hexenal 5 mM reduced the disease severity, compared to the control. Protection conferred by MeJA could be due to the activation of the JA-defence pathway, as it induced in tobacco the accumulation of LOX, AOC and defensin genes transcripts and did not inhibit fungal germ tube growth. Protection conferred by (E)-2-hexenal could be mainly attributable to its antimicrobial activity, as it did not induce the accumulation of genes transcripts but inhibited fungal germ tube growth. The increased disease severity caused by ( E)-β-ocimene 0.18 mM could be due to the in vitro stimulation of conidial germination. At the above tested concentrations, the three compounds significantly reduced Myzus persicae infestation with respect to the control. Thus, the defence responses induced by the pathogen were able to protect the plant also from aphid attacks emphasizing the importance of studying plant responses also in a multitrophic in teraction systemI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
