The effect of Trichoderma volatiles on the growth and enzyme production of Serpula lacrymans
S N Humphris, A Bruce, R E Wheatley
Although various authors have reported the biological control of Serpula lacrymans by Trichoderma spp. the mode of antagonism employed by Trichoderma is not yet clear. The work presented here concentrates on the production of anti-fungal volatiles for inhibition of S. lacrymans growth. Volatile mediated interactions were examined between four S. lacrymans isolates and a range of nine known Trichoderma antagonists. Interactions were evaluated on two agar media and Scots pine sawdust. Results indicated that S. lacrymans isolates were significantly inhibited by volatile organic compounds (VOCs) produced by Trichoderma isolates, with some Trichoderma isolates being more potent producers of inhibitory VOCs than others. The production of VOCs was influenced by the nutrient composition of the Trichoderma growth media with generally greater inhibition being produced when Trichoderma isolates were cultured on nutrient rich media. Results from cultures grown on sawdust gave greater inhibition than low nutrient medium but less than when cultures were grown on malt extract agar. The effect of VOCs on fungal enzyme production was also examined by testing tyrosinase, cellulase and peroxidase. Results indicated that production of cellulase was not affected by Trichoderma volatiles and that tyrosinase was not released by any of the S. lacrymans isolates. Inhibition of growth of the S. lacrymans isolates by Trichoderma volatiles increased peroxidase activity. The paper discusses the potential role of VOC production in the biological control of dry rot.
Keywords: BIOLOGICAL CONTROL; TRICHODERMA SPP; SERPULA LACRYMANS; VOC PRODUCTION