David Wendehenne, and
Université de Bourgogne, INRA 1088, and CNRS 5184, Unité Mixte de Recherche Plante-Microbe-Environnement, 17 Rue Sully, F-21000 Dijon, France
Go to article:
Accepted 19 April 2010.
The molecular mechanisms underlying the process of priming are poorly understood. In the present study, we investigated the early signaling events triggered by β-aminobutyric acid (BABA), a well-known priming-mediated plant resistance inducer. Our results indicate that, in contrast to oligogalacturonides (OG), BABA does not elicit typical defense-related early signaling events nor defense-gene expression in grapevine. However, in OG-elicited cells pretreated with BABA, production of reactive oxygen species (ROS) and expression of the respiratory-burst oxidase homolog RbohD gene were primed. In response to the causal agent of downy mildew Plasmopara viticola, a stronger ROS production was specifically observed in BABA-treated leaves. This process was correlated with an increased resistance. The NADPH oxidase inhibitor diphenylene iodonium (DPI) abolished this primed ROS production and reduced the BABA-induced resistance (BABA-IR). These results suggest that priming of an NADPH oxidase--dependent ROS production contributes to BABA-IR in the Vitis-Plasmopara pathosystem.
The American Phytopathological Society, 2010