Role of pathogen-induced volatiles in the Nicotiana tabacum-Golovinomyces cichoracearum interaction.
Plant injuries activate signal transduction cascades mediated by the plant hormones, which lead to enhanced expression of defence related genes and/or to changes in the emission of volatile organic compounds that can act as semiochemicals. In this research we demostrated that infection with the biotrophic pathogen Golovinomyces cichoracearum (DC.) V.P. Heluta (ex Erysiphe cichoracearum DC.), the causal agent of powdery mildew, led in the susceptible host Nicotiana tabacum L. cv Havana 425 to an increased emission of volatile compounds including Methyl-jasmonate (MeJA), (E)-2-hexenal and (E)-β-ocimene. Furthermore we investigated the role of these volatiles in the plant-pathogen interaction. Exogenous application of MeJA induced in tobacco an increase in the transcripts level of the defence related genes lipoxygenase, allene oxide cyclase and defensin and a decrease in the severity of the infection. Qualitative and quantitative differences in volatile compounds emission were showed also in MeJA-treated plants, where the emission of (E)-β-ocimene was significantly increased instead (E)-2-hexenal was not detected. Application of (E)-2-hexenal reduced the severity of powdery mildew while application of (E)-β-ocimene did not. Since (E)-2-hexenal did not activate in tobacco the accumulation of the above reported genes transcripts and the plant cell death, the reduction of the infection severity could be attributable to its inhibitory activity on the fungal germ tube growth. Our data highlight the contributions of natural substances that can act, directly or indirectly, against phytopathogens. In the global context of sustainability, food safety and environmental protection, such semiochemicals represent an alternative and promising approach to integrated pest management.
Department of Agricultural and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, I-06121 Perugia, Italy. mara.quaglia@unipg.it
Mara
M
Quaglia
Mario
M
Fabrizi
Antonio
A
Zazzerini
Claudia
C
Zadra
D000085:Acetates / Q000378:metabolism / Q000494:pharmacology*; D000080462:Acyclic Monoterpenes; D000447:Aldehydes / Q000378:metabolism; D000475:Alkenes / Q000378:metabolism; D000890:Anti-Infective Agents / Q000378:metabolism; D001203:Ascomycota / Q000502:physiology*; D003517:Cyclopentanes / Q000378:metabolism / Q000494:pharmacology*; D023082:Defensins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D054884:Host-Pathogen Interactions; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism; D009822:Oils, Volatile / Q000378:metabolism*; D054883:Oxylipins / Q000378:metabolism / Q000494:pharmacology*; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D010937:Plant Growth Regulators / Q000378:metabolism / Q000494:pharmacology*; D057865:Plant Immunity / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000276:immunology / Q000382:microbiology / Q000502:physiology; D010938:Plant Oils / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013997:Time Factors; D014026:Nicotiana / Q000187:drug effects / Q000276:immunology / Q000382:microbiology / Q000502:physiology*
D000085:Acetates; D000080462:Acyclic Monoterpenes; D000447:Aldehydes; D000475:Alkenes; D000890:Anti-Infective Agents; D003517:Cyclopentanes; D023082:Defensins; D009822:Oils, Volatile; D054883:Oxylipins; D010937:Plant Growth Regulators; D010938:Plant Oils; D010940:Plant Proteins; C443996:beta-ocimene; C051750:2-hexenal; C072239:methyl jasmonate; D008084:Lipoxygenase; D019746:Intramolecular Oxidoreductases; C021377:hydroperoxide isomerase