Abstract:
The aggressive mushroom competitor, Trichoderma harzianum biotype Th4,
produces volatile antifungal secondary metabolites both in culture and during the
disease cycle in compost. Th4 cultures produced one such compound only when
cultured in the presence of Agaricus bisporus mycelium or liquid medium made
from compost colonised with A. bisporus. This compound has TLC and UVabsorption
and characteristics indicating that it belongs to a class of pyrone
antibiotics characterised from other T. harzianum biotypes. UV absorption spectra
indicated this compound was not 6-pentyl-2H-pyran-one (6PAP), the volatile
antifungal metabolite widely described in Th1. Furthermore, this compound was
not produced by Th1 under any culture conditions. Mycelial growth of A. bisporus,
Botrytis cinerea and Sclerotium cepivorum was inhibited in the presence of this
compound through volatility , diffusion and direct application. This indicates that
Th4 produces novel, volatile, antifungal metabolites in the presence of A. bisporus
that are likely involved in green mould disease of mushroom crops.
