Antifungal activity of volatile organic compounds from Trichoderma virens

Trichoderma species have been widely used as biofungicides and biofertilizers to control many plant pathogens and to enhance plant growth and its resistance. The production of volatile organic compounds (VOCs) is one of the modes of actions of Trichoderma sp. to directly inhibit pathogenic fungi/bacteria and to induce systemic resistance of plants. Forty-three VOCs were identified from seven stains of T. virens which were analyzed using gas chromatography-mass spectrometry (GC-MS). Solid phase micro-extraction (SPME) was performed prior to sample injection. Most of the compounds were sesquiterpenes known as antifungal chemicals (i.e aromanderen, element, cadinene, and 2-Octanone), monoterpene (limonene and bisnorhopane), and fatty acids (oleic acid, and monopalmtin). Other VOCs were identified having antifungal activity and plant growth promoters such as caryophyllene and thojupsene. In vitro assay of antifungal activity showed that VOCs produced by T.virens inhibited the growth of R.solani up to 59.4% at 5 days after inoculation and influenced the morphological abnormalities of R. solani hypae. T. virens strain V3 (T.v3) and V4 (T.v4) showed the ability to reduce more than 50% of R.solani growth and were potential to be used as biocontrol agents.