Foliar Pulverization of Tetraclinis Articulata Essential Oil Induces Antioxidant Status and Defense Genes Expression in Tomato Plants Against Botrytis Cinerea Infection

Over the last decades, researches were focused on finding novel pesticides with a lower toxicity towards the environment and human health. Essential oils (EOs) of medicinal plants are considered as potential next-generation pesticides to control plant pathogens and pests through different mechanisms of action including the activation of plant defenses. In previous study Tetraclinis articulata essential oil (TAEO) proved to be effective in controlling tomato grey mould in greenhouse conditions by foliar pulverization, so herein we would investigate its effect on some tomato defense mechanisms. The pretreatment of pathogen infected tomato plants with TAEO emulsion enhanced the activities of the antioxidant enzymes SOD, CAT, APX and GPX, total polyphenols content, and total antioxidant activity leading to a substantial decrease in IC 50 of free radical-scavenging activity and H 2 O 2 content. A quite similar antioxidant status in TAEO emulsion treated or B. cinerea infected plants was observed, likely indicating that treatment with essential oil mimic an infection condition in tomato plants leading to a priming status which may explain a better antioxidant response to B. cinerea infection in TAEO emulsion pretreated plants. Pretreatment with TAEO emulsion of B. cinerea infected plants increased chlorophyll content at all studied time points. The qRT-PCR analysis of the expression of the defense genes Chitinase SlChi, the transcription factors SlWRKY and SlAP2/ERF , Lipoxygenase SlLOX , and Thioredoxin SlTRX showed that they were up-regulated as early as 12 hpi sustained with a second increase at 48 hpi in TAEO emulsion pretreated and infected tomato plants. These results suggest the potential use of TAEO emulsion as natural product to induce tomato antioxidant status and activate defense genes to reduce grey mould attack in greenhouses.