Plant Extract Treatments Induce Resistance to Bacterial Spot by Tomato Plants for a Sustainable System

Abstract

The aim of this study is to assess the effect of extracts of Nerium oleander, Eucalyptus chamadulonsis and Citrullus colocynthis against bacterial spot disease of tomato and to investigate the induction of resistance by tomato (Solanum lycopersicum) in order to promote a sustainable management system. The antibacterial activity of aqueous and ethanol plant extracts was tested against Xanthomonas axonopodis pv. vesicatoria, isolate PHYXV3, in vitro and in vivo. The highest antibacterial activity in vitro was obtained with C. colocynthis, N. oleander and E. chamadulonsis, respectively. In vivo, ethanol extracts of N. oleander and E. chamadulonsis were more effective than aqueous extracts in reducing pathogen populations on tomato leaves. Under greenhouse conditions, application of the plant extracts at 15% (v/v) to tomato plants significantly reduced disease severity and increased the shoot weight of ‘Super Marmande’ tomato. In most cases, plant extracts significantly increased total phenol and salicylic acid content of tomato plants compared to either healthy or infected ones. In addition, C. colocynthis and E. chamadulonsis extracts significantly increased peroxidase activity while only E. chamadulonsis increased polyphenol oxidase after infection with the causal agent. The results indicated that the plant extracts showed promising antibacterial activity and could be considered an effective tool in integrated management programs for a sustainable system of tomato bacterial spot control.

Biological Control of Celery Powdery Mildew Disease Caused by Erysiphe heraclei DC In Vitro and In Vivo Conditions

“…Defense-related enzymes such as peroxidase and polyphenol oxidase are mentioned as the plant induced systemic resistance (ISR) that correlates with disease control. These enzymes produced by the biosynthesis of plant metabolites, such as phenolic compounds, flavonoids, tannins and lignin [47,48], play an important role in plant stress tolerance, especially on fungal, bacterial and viral pathogens [49,50]. Many studies have indicated that the increase of defense-related enzymes activity due to greater accumulation of phenolic compounds can offer protection against plant diseases [25,26].…”

Isolation of Pseudomonas syringae pv. Tomato strains causing bacterial speck disease of tomato and marker-based monitoring for their virulence

“…At 3–4 leaf stage, seedlings were transplanted to new identical pots that were placed in greenhouse of the Department of Agriculture, Assiut University, Egypt. To fulfill the nutrient requirements, slow release fertilizer NPK (12:4:6) was added into soil [ 24 ]. The optimal temperature (30 ± 2 °C) and relative humidity (68–80%) inside the greenhouse was maintained and plants were irrigated as per requirement.…”

Antifungal activity of eco-safe nanoemulsions based on Nigella sativa oil against Penicillium verrucosum infecting maize seeds: Biochemical and physiological traits

“…Leaf tissue (1 g) collected at the third leaf stage (14 DPS) was homogenized in 5 ml of 0.05 M phosphate buffer (pH 7.0) containing 10% polyvinylpyrrolidone (PVP-SIGMA) and 0.1 M ethylene di-amine-tetra-acetic acid (EDTA-SIGMA) and centrifuged at 14,000 rpm for 20 min at 4°C. POD activity was measured by the method of Abo-Elyousr et al (2020) . The assay mixture contained 0.1 ml enzyme extract, 1.35 ml 0.1 M mM MES buffer (pH 5.5), 0.05% H 2 O 2 , and 0.1% phenylenediamine.…”