Antifungal effect of volatile organic compounds (VOCs) release from Antarctic bacteria under postharvest conditions

Abstract

The generation of biological control agents for postharvest fungal control has prompted the search for different natural sources due to studies indicating adverse effects that may be related to the use of conventional fungicides (e.g., SO2). Some bacteria that have the ability to generate volatile organic compounds (VOCs) with antifungal activity stand out in this regard. Thus, the Antarctic bacterium Pseudomonas sp. AN3A02, which can grow in very cold environments with low nutrient availability, has shown a fungistatic effect on Botrytis cinerea in dual culture. In this study, in vitro assays were performed to evaluate its effect and activity on strains of B. cinerea isolated from blueberries using dual-plate assays. An antifungal assay (in vivo) was performed by artificial wounding on blueberries inoculated with B. cinerea (1 ×106 conidia/mL) and stored at 0 °C for 20 d plus 3 d at 20 °C. The results obtained showed that in the presence of the bacteria, the severity of gray mold on blueberries was reduced by 71.38 %. In addition, this bacterium released a diversity of VOCs, including alcohols (1-octanol, 10.3 %), aldehydes (paraldehyde, 2.1 %), esters (ethyl butyrate, 4 %; isoamyl acetate, 2 %), ketones (2-nonanone, 1.4 %), terpenes (linalool, 1.9 %; D-limonene, 0.7 %), phenolic derivatives (2,4-di-tert-butylphenol, 2.5 %) and other groups, which were identified by GC–MS. The release of VOCs affects and modifies the hyphae and germ tube of B. cinerea, influencing its growth. Therefore, a new and environmentally friendly alternative for postharvest pathogen control could be generated based on this Antarctic microorganism.