Molecular responses of phytopathogenic fungi to essential oil application: current knowledge and perspectives

Plants are increasingly threatened by abiotic and biotic stresses such as climate change, intensive monoculture planting, and pathogenic agents. Phytopathogenic fungi cause substantial crop production losses and for their control, synthetic fungicide s are intensively used. However, it is now well established that these traditional fungicides have adverse effects on human health and the environment. Essential oils (EOs) extracted from plant materials could constitute a promising environmentally safe strategy, given their low environmental impact. Their modes of action on plant fungal pathogens have been extensively studied under both in vitro and in vivo conditions. Among the active compounds detected in EOs, terpene hydrocarbons and oxygenated derivatives have been reported to inhibit fungi by damaging cell structures through disruption of the cell membrane, inhibition of ergosterol biosynthesis, blockage of the respiratory chain, reduction of spore germination, and interference with cell division processes. In addition, EOs induce oxidative stress by enhancing the production of reactive oxygen species (ROS), leading to protein, lipid, and DNA damage, and consequently to cell death. From this evidence, EOs can represent a sustainable approach to fungal pathogen control. Thus, the current mini-review aims to summarize the state of the art regarding the molecular responses of phytopathogenic fungi treated with EOs, using omics approaches such as transcriptomics, proteomics, metabolomics, and lipidomics.