Abstract
Many species of Trichoderma produce secondary metabolites such as volatile organic
compounds (VOCs) that reduce plant diseases and promote their growth. In this work
we evaluated the antagonistic effects of VOCs released by eight strains of two Trichoderma
species against Pyrenophora teres Drechsler, the causal agent of barley net blotch. Antagonism
was estimated based on the percentage of mycelial growth inhibition according
to the confronted cultures method. VOCs extraction and identification were performed
by gas chromatography and mass spectrometry, through different methodologies for
VOCs emitted by antagonists and pathogens alone or when confronted. VOCs produced
by all Trichoderma strains inhibited mycelial growth of the pathogen in a range of 3 to
32%, showing weak and unpigmented mycelia with vacuolization. In addition, P. teres
stimulated the release of VOCs by both Trichoderma species. The major groups of VOCs
detected were sesquiterpenes, followed by diterpenes, terpenoids and eight-carbon compounds.
This is the first report about characterization of volatiles emitted by Trichoderma
in the presence of P. teres.
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