The peach (Prunus persica) defensin PpDFN1 displays antifungal activity through specific interactions with the membrane lipids. (12th June 2012)

• Record Type: Journal Article
• Authors: Nanni, V.; Zanetti, M.; Bellucci, M.; Moser, C.; Bertolini, P.; Guella, G.; Dalla Serra, M.; Baraldi, E.
• Is Part Of: Plant pathology. Volume 62:Number 2(2013:Apr.)
• Page Start: 393
• Page End: 403
• Publication Date: 2012-06-12
• Subjects: Agricultural pests -- Periodicals; Plant diseases -- Periodicals; 632
• DOI: 10.1111/j.1365-3059.2012.02648.x
• Languages: English
• ISSNs: 0032-0862

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p> <italic>Ppdfn1</italic> is a defensin gene previously identified in peach (<italic>Prunus persica</italic>). The biological role of <italic>Ppdfn1</italic> was investigated by analysing its expression profile in leaves, flowers and fruits, either inoculated with the <italic>Monilinia laxa</italic> fungal pathogen or mock‐inoculated. <italic>Ppdfn1</italic> expression was highest in flowers and, in fruits, did not vary upon <italic>M. laxa</italic> inoculation. To characterize the PpDFN1 antifungal activity, the recombinant mature peptide was expressed in <italic>Escherichia coli</italic> and purified; recombinant PpDFN1 displays antifungal activity against <italic>Botrytis cinerea, M. laxa</italic> and <italic>Penicillium expansum</italic>, with IC<sub>50</sub> values of 15·1, 9·9 and 1·1 μg mL<sup>−1</sup>, respectively. Treatment of fungal hyphae with FITC‐labelled PpDFN1 indicated that the peptide is not internalized by fungal hyphae, but localizes on their external cell surface. At this site, PpDFN1 is capable of membrane destabilization and permeabilization, as demonstrated by SYTOX Green fluorescence uptake by the treated mycelia. Using artificial lipid monolayers, it was shown that PpDFN1 interacts with sphingolipid‐containing membranes; however the strongest interaction occurs with monolayers composed of lipids extracted from sensitive fungi, such as <italic>P</italic>. <italic>expansum</italic>. These data suggest that the lipid composition of fungal membranes is of key relevance for defensin specificity.</p> </abstract>