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Insights into fruit defense mechanisms against the main post-harvest pathogens of apples and oranges

Rosario Torres: IRTA, XaRTA-Postharvest, Edifici Fruitcentre

<div>Despite the current use of chemical fungicides, <em>Penicillium digitatum </em>and <em>Penicillium expansum</em>, the most devastating pathogens of citrus and pome fruits, respectively, are still responsible of important economic losses during postharvest handling worldwide. Current trends are focused on finding new rational and environmental friendly control alternatives. In this sense, a better understanding of the fruit-pathogen interaction may be consider as a novel perspective for the control of postharvest diseases. The main goal of these studies was to obtain a better understanding of the fruit’s defence response against both pathogens. For such purposes, both the lignification process and the role of ethylene production on compatible and non-host interactions was studied using pathological, biochemical and molecular approaches. Concerning lignification, the main results indicate that orange response to wounding is slower than the response to the pathogen attack. In apples, the resulting data from transcriptomic analysis provide further evidence that apples inoculated with <em>P. expansum</em> exhibit significant upregulation of defence-related genes and genes involved in detoxification of reactive oxygen species. The results related to ethylene biosynthesis on apples showed that <em>P. expansum</em> and <em>P. digitatum</em> could differentially alter the fruit ethylene production, probably by the manipulating the endogenous fruit ethylene biosynthesis, leading to the circumvention or suppression of effective defences and hence facilitating its colonization.</div>