Response of vitis vinifera cell cultures to phaeomoniella chlamydospora : changes in phenolic production, oxidative state and expression of defence-related genes

Cell suspension cultures of Vitis vinifera cv. Vinhão (Vv) were used to study the putative response of V. vinifera to Phaeomoniella chlamydospora (Pc), a fungus frequently associated with esca and grapevine decline. Cells were elicited with a Pc autoclaved biomass extract and methyl jasmonate (MeJ). Phenolic production was evaluated by HPLC-DAD and HPLC-MS/MS. Phenolic production of Vv cells significantly changes after elicitation. Compared to control, Vv cells elicited by Pc extract increase their stilbene production 20-fold and those elicited by MeJ increase stilbenic production 9-fold. In both cases, there is de novo production of viniferin type compounds. We also analyzed the oxidative burst of Vv cells after elicitation with Pc extract and MeJ, using the probe 2′,7′-dichlorodihydrofluorescein diacetate. Adding Pc extract induces an oxidative burst thatshows a biphasic pattern in Vv cells. Moreover, the induction of 7 defence-related genes expression in Vvcell cultures upon Pc extract elicitation was investigated employing semi-quantitative RT-PCR. Elicitation increases the expression of class 6 and class 10 pathogenesis-related proteins, β-1,3-glucanase, class III chitinase, lipoxygenase, phenylalanine ammonia lyase and stilbene synthase. Therefore, Vv in vitro cell cultures could be an important tool to study esca disease, since they offer a simple, rapid and selective way to evaluate plant/fungus interactions.Fundação para a Ciência e a Tecnologia (FCT