Volatile organic compounds emitted by Trichoderma azevedoi promote the growth of lettuce plants and delay the symptoms of white mold

Abstract Lettuce (Lactuca sativa L.) is cultivated all year round and can be affected by several diseases that limit its commercial production, including white mold, caused by the fungus Sclerotinia sclerotiorum. The use of antagonistic fungi, such as those of the genus Trichoderma, has been shown to be a control option for white mold. Some species of Trichoderma are producers of a variety of volatile organic compounds (VOCs), capable of promoting plant growth and of inhibiting the development of phytopathogens. The objective of this study was to evaluate the ability of VOCs emitted by T. azevedoi CEN1241 to promote plant growth and delay the symptoms of white mold, in lettuce cv. Elisa (Sakata®). The plants were exposed to the VOCs of the CEN1241 using the inverted Petri dish technique, and voile homemade bags filled with soil, forming an atmosphere sharing set. Lettuce plants were also inoculated with mycelium of S. sclerotiorum exposed three consecutive times to CEN1241 VOCs. Thirty-three VOCs emitted by CEN1241 were identified by gas chromatography and mass spectrometry (GC–MS). These VOCs promoted plant growth and increased the content of chlorophyll and carotenoids. The symptoms of white mold were delayed and the severity of the disease decreased in 43.42% on second generation and 78.83% on third generation of exposure to VOCs, related to the control.