How Iron Could Be Involved in Esca Fungi Development

Iron reduction capability was detected by ferrozine assay in Phaeomoniella chlamydospora, Phaeacremonium aleophilum and Fomitiporia punctata. On the other hand, the Chrome Azurol S (CAS) assay demonstrated that low molecular weight chelator agents were produced by P. chlamydospora, P. aleophilum, Libertella blepharis and F. punctata. Foliar analysis carried out at harvest showed higher levels of the iron in symptomatic than in asymptomatic leaves. Conversely, levels of the other transition metals (copper, manganese and zinc), and of calcium and magnesium were basically similar in symptomatic and asymptomatic leaves. A possible relationship between iron, esca fungi and host-plant was hypothesized.