Effect of Volatiles from Trichoderma species on the regulation of protein synthesis in Serpula lacrymans isolates
S Humphris, R Wheatley, E Buultjens, A Bruce
The growth of wood decay fungi has previously been shown to be inhibited by volatile organic compounds (VOCs) from selected Trichoderma isolates. No mechanism of action has however been established for such inhibition. This paper reports the effects of VOCs produced by Trichoderma pseudokoningii, T. viride and T. aureoviride on the growth of four dry rot isolates and corresponding protein synthesis in two of these Serpula lacrymans strains. Volatile inhibition of growth was measured using a simple plate bioassay with S.lacrymans mycelium subsequently extracted and protein profiles analysed by SDS-PAGE. Two S.lacrymans strains isolated from building timbers were generally more sensitive to the Trichoderma VOCs compared with a strain isolated from the Himilayas or a standard lab culture strain. VOCs from T. aureoviride and T. viride affected protein synthesis in both target S. lacrymans strains, but those from T. pseudokoningii.had no effect. These results mirrored the patterns of growth inhibition in the target fungi with VOCs from T.pseudokoningii having little effect on growth of the dry rot fungi. Interestingly, when the antagonists were removed growth of the S. lacrymans isolates resumed and the original protein patterns were restored. This suggests that the VOCs act on the basic expression of proteins by the S. lacrymans rather than interfering with protein function after synthesis.