Antibacterial activity of some essential oils on bacterial spot disease of tomato plant caused by Xanthomonas axonopodis pv. vesicatoria

Abstract

A B S T R A C TBacterial spot disease caused by Xanthomonas axonopodis pv. vesicatoria is considered one of the major diseases of tomato crop worldwide. The objective of this paper was to study the effect of certain essential oils (EOs), lemongrass, oleum and thyme, on X. axonopodis pv. vesicatoria (PHYX14) for controlling bacterial spot disease in tomato plants. The tested three essential oils (EOs) showed antibacterial activity in vitro test at 1:10 concentration against the PHYX14.Thyme oil exhibited the highest inhibition against PHYX14 followed by lemongrass and finally oleum. Under greenhouse conditions, the effect of EOs on the bacterial spot of tomato was evaluated on tomato seedlings. Thyme oil exhibited the highest reducing of tomato bacterial spot followed oleum and then lemongrass. Results indicated that the application of the tested (EOs) to tomato plants two days after the infection caused the highest reduction of disease severity. While the application of oleum oil exhibited the highest induction of the oxidative enzymes, peroxidase (PO) and polyphenol enzyme (PPO). Also increased total phenolic contents of tomato leaves followed lemongrass and then thyme oil as compared by control. The application of EOs two days before the infection caused the highest induction of PO, PPO enzymes and total phenolic contents in tomato leaves than two days after the inoculation.

Potential and Metabolic Pathways of Eugenol in the Management of Xanthomonas perforans, a Pathogen of Bacterial Spot of Tomato

“…Eugenol is an important component of essential oils from many plants. Essential oils extracted from clove, cinnamon, thyme, and Origanum species have been shown to inhibit X. vesicatoria in vitro and in vivo, as well as when being used as seed treatment [ 52 , 53 , 54 , 55 ]. Eugenol has also been shown to reduce seed infection with X. campestris pv.…”

Inhibitory Activity and Mechanism of Action with Thymol against the Blueberry Pathogenic Fungi Caused by Neopestalotiopsis clavispora

“…Thymol (2-isopropyl-5-methylphenol) is the main monoterpene phenol occurring in essential oils isolated from plants belonging to the Lamiaceae family (Thymus, Ocimum, Origanum, and Monarda genera) and other plants such as those belonging to the Verbenaceae, Scrophulariaceae, Ranuncolaceae, and Apiaceae families [8]. Because of its high safety, wide range of sources, lack of chemical residues, broad-spectrum antifungal properties, and other characteristics [9,10], it has been authorized by the Federal Drug Administration (FDA) for food and as a food additive, and it has since been widely utilized in the field of food preservation [11]. Thymol has been demonstrated to be capable of being transformed into microencapsulation [12] and antimicrobial films [13] in order to effectively extend the freshness period of fruits and vegetables.…”