Effects of three esca-associated fungi on Vitis vinifera L.:: III.: Enzymes produced by the pathogens and their role in fungus-to-plant or in fungus-to-fungus interactions

When the esca-associated fungi Phaeomoniella chlamydospora (Pch), Togninia minima (Tmi) and Fomitiporia mediterranea (Fme) were grown in liquid stationary cultures, it was seen that they were able to live in media containing resveratrol (RES) or tannic acid (TA) as the sole carbon source and that the fungi were able to convert both compounds. Particular attention is paid here to detecting RES and TA conversion. Pch, Tmi and Fine were partially inhibited by RES or TA. Pch, Tmi and Fine produced extracellular tannase, laccase and peroxidase enzymes in liquid or agarized cultures, whether glucose was present or not. When colonies of Pch, Tmi and Fine were confronted, they showed spatially and temporally heterogeneous patterns of laccase and peroxidase activity. The results indicate the nonsynergistic, competitive association of Pch and Tmi and the inhibition of Fine growth. Muconic acid, a well-known intermediate in a large number of lignin and phenol oxidative processes, can partly or completely inhibit the lignolytic agent Fine, but is tolerated by Pch and Tmi. An explanation for wood pigmentation patterns by Pch, Tmi and Fme is given. (c) 2007 Elsevier Ltd. All rights reserved.