Volatile organic compounds in greenhouse: Discovery of volatile biomarkers related to fungal infection by Botrytis cinerea in tomato plants

Abstract

The development of fungal disease in greenhouse plants can result in limited production and great economic losses for the producer. Early detection and identification of disease in plants before visible symptoms appear, could contribute to a more effective and sustainable production for Norwegian growers. Cucumber (Cucumis sativus L.) and tomato (Solanum lycopersicum L.) are common and important plants produced in Norwegian greenhouses. Pythium sp. root rot and grey mould caused by Botrytis cinerea infection are some of the most severe plant diseases, and particularly connected to cucumber and tomato plants. Both diseases can be difficult to notice by visual observation and are easily transmitted within a crop.

Current research on volatile organic compounds (VOCs) is mainly focused on plant response to herbivores and fruit quality, while the research related to pathogens is more limited. If fungal infection causes a release of unique VOCs specific to the disease, these can be detected by highly sensitive analytical method HS-SPME-GC-MS. This is a non-invasive method that can be used to test for specific disease biomarkers without harming of the plants.

Here we show that a large number of VOCs can be identified by this method. The sesquiterpenes alpha-copaene and cis-thujopsene are classified as candidate biomarkers for fungal infection in tomato plants, and possibly also for the specific interaction of B. cinerea related disease. The monoterpenes beta-phellandrene and (+)-4-carene were also identified as important compounds released in high concentrations, likely associated with general stress response in tomato plants and tomato-related smell components.