Effects of three esca-associated fungi on Vitis vinifera L.: I. Characterization of secondary metabolites in culture media and host responses to the pathogens in calli

摘要

Phaeomoniella chlamydospora (Pch) and Togninia minima (Tmi) produced scytalone, isosclerone and pullulans in liquid cultures, as well as in calluses. Secondary metabolites and host defence compounds were shown to occur in calluses of Vitis vinifera cv. Italia and cv. Matilde infected by the esca-associated fungi Pch, Tmi and Fomitiporia mediterranea (Fme). Calluses of both cvs. were grown as dual cultures with Pch, Tmi and Fme. The fungi grew well in the presence of calluses of both cvs., but callus growth was reduced. Accumulation and changes of total phenolics and recurring phenolics, and of two phytotoxic pentaketides and pullulans were analysed by HPLC. On comparing results for cv. Italia and cv. Matilde, it can be seen that concentrations of phenolics are strongly related to the cv. The paper discusses the possible relationship between melanin biosynthesis in Pch and Tmi, which utilize pentaketide metabolites as intermediates and their pathogenicity related to phytotoxity of scytalone and isosclerone..