Volatile Organic Compounds Produced by Trichoderma asperellum with Antifungal Properties against Colletotrichum acutatum

Managing plant diseases caused by phytopathogenic fungi, such as anthracnose caused by <i>Colletotrichum</i> species, is challenging. Different methods have been used to identify compounds with antibiotic properties. <i>Trichoderma</i> strains are a source of novel molecules with antifungal properties, including volatile organic compounds (VOCs), whose production is influenced by the nutrient content of the medium. In this study, we assessed the VOCs produced in dual confrontation systems performed in two culture media by <i>Trichoderma</i> strains (<i>T. atroviride</i> IMI206040, <i>T. asperellum</i> T1 and T3, and <i>Trichoderma</i> sp. T2) on <i>Colletotrichum acutatum</i>. We analysed the VOC profiles using gas chromatography coupled with mass spectrometry. The Luria Bertani (LB) medium stimulated the production of VOCs with antifungal properties in most systems. We identified 2-pentyl furan, dimethyl disulfide, and α-phellandrene and determined their antifungal activity in vitro. The equimolar mixture of those VOCs (250 µM ea.) resulted in 14% <i>C. acutatum</i> diametral growth inhibition. The infective ability and disease severity caused by the mycelia exposed to the VOCs mixture were notably diminished in strawberry leaves. Application of these VOCs as biofumigants may contribute to the management of anthracnose. LB represents a feasible strategy for identifying novel VOCs produced by <i>Trichoderma</i> strains with antifungal properties.