Application of Volatile Antifungal Plant Essential Oils for Controlling Pepper Fruit Anthracnose by Colletotrichum gloeosporioides

Molecular Insights into the Role of the MET30 Protein and Its WD40 Domain in Colletotrichum gloeosporioides Growth and Virulence

Colletotrichum gloeosporioides is a major phytopathogen responsible for anthracnose in Capsicum annuum (pepper) which leads to significant yield losses. At present, the molecular mechanism of C. gloeosporioides pathogenesis is not very clear. In this study, we focused on the MET30 protein and its key WD40 domain, with an emphasis on its role in the biological functions of C. gloeosporioides. Bioinformatics analysis revealed that the MET30 protein contains a conserved F-box domain and multiple WD40 repeats, which interact with other proteins to participate in various cellular processes, including nutrient acquisition, stress responses, and pathogenicity. Gene knockout and complementation experiments demonstrated that deleting the MET30 protein or its WD40 domain significantly reduced the rates of spore production and hyphal growth while increasing tolerance to environmental stresses such as high salinity and oxidative stress. Furthermore, pathogenicity assays revealed that the WD40 domain of the MET30 protein is crucial for regulating fungal pathogenicity, as mutants lacking WD40 domains presented increased virulence on pepper leaves. These findings suggest that the WD40 domain, in synergy with the MET30 protein, regulates the pathogenicity and stress response of C. gloeosporioides, provides new insights into the molecular mechanisms of anthracnose, and offers potential strategies for effective disease control.

Potentiality of Beneficial Microbe Bacillus siamensis GP-P8 for the Suppression of Anthracnose Pathogens and Pepper Plant Growth Promotion

This study was carried out to screen the antifungal activity against Colletotrichum acutatum, Colletotrichum dematium, and Colletotrichum coccodes. Bacterial isolate GP-P8 from pepper soil was found to be effective against the tested pathogens with an average inhibition rate of 70.7% in in vitro dual culture assays. 16S rRNA gene sequencing analysis result showed that the effective bacterial isolate as Bacillus siamensis. Biochemical characterization of GP-P8 was also performed. According to the results, protease and cellulose, siderophore production, phosphate solubilization, starch hydrolysis, and indole-3-acetic acid production were shown by the GP-P8. Using specific primers, genes involved in the production of antibiotics, such as iturin, fengycin, difficidin, bacilysin, bacillibactin, surfactin, macrolactin, and bacillaene were also detected in B. siamensis GP-P8. Identification and analysis of volatile organic compounds through solid phase microextraction/gas chromatography-mass spectrometry (SPME/GC-MS) revealed that acetoin and 2,3-butanediol were produced by isolate GP-P8. In vivo tests showed that GP-P8 significantly reduced the anthracnose disease caused by C. acutatum, and enhanced the growth of pepper plant. Reverse transcription polymerase chain reaction analysis of pepper fruits revealed that GP-P8 treated pepper plants showed increased expression of immune genes such as CaPR1, CaPR4, CaNPR1, CaMAPK4, CaJA2, and CaERF53. These results strongly suggest that GP-P8 could be a promising biocontrol agent against pepper anthracnose disease and possibly a pepper plant growth-promoting agent.

Helichrysum stoechas (L.) Moench Inflorescence Extract for Tomato Disease Management

Helichrysum stoechas is a singular halophyte that has been shown to have anti-inflammatory, antioxidant, and allelopathic properties. In the work presented herein, we have characterized its inflorescences hydromethanolic extract and assessed its antifungal activity for the pre- and postharvest management of tomato crop diseases. Gas chromatography-mass spectrometry characterization of the extract showed that 4-ethenyl-1,3-benzenediol, 2,3-dihydro-benzofuran, quinic acid, 3,5-dihydroxy-6,7,8-trimethoxy-2-phenyl-4H-1-benzopyran-4-one, 1,6-anhydro-β-D-glucopyranose, catechol, scopoletin, and maltol were the main constituents. The co-occurrence of pyranones, benzenediols, and quinic acids as phytoconstituents of H. stoechas extract resulted in promising in vitro minimum inhibitory concentrations of 500, 375, 500, 187.5, 187.5, and 375 μg·mL-1 against mycelia of Alternaria alternata, Colletotrichum coccodes, Fusarium oxysporum f. sp. lycopersici, Rhizoctonia solani, Sclerotinia sclerotiorum, and Verticillium dahliae, respectively. Further, to assess the potential of H. stoechas inflorescence extract for postharvest tomato crop protection, ex situ tests were conducted against C. coccodes, obtaining high protection at a dose of 750 μg·mL-1. Taking into consideration that the demonstrated activity is among the highest reported to date for plant extracts and comparable to that of the synthetic fungicides tested as positive controls, H. stoechas inflorescence extract may be put forward as a promising biorational and may deserve further testing in field-scale studies.

Vapours from plant essential oils to manage tomato grey mould caused by Botrytis cinerea

Tomato grey mould has been a great concern during tomato production. The in vitro antifungal activity of vapours emitted from four plant essential oils (EOs) (cinnamon oil, fennel oil, origanum oil, and thyme oil) were evaluated during in vitro conidial germination and mycelial growth of Botrytis cinerea, the causal agent of grey mould. Cinnamon oil vapour was the most effective in suppressing conidial germination, whereas the four EOs showed similar activities regarding inhibiting mycelial growth in dose-dependent manners. The in planta protection effect of the four EO vapours was also investigated by measuring necrotic lesions on tomato leaves inoculated by B. cinerea. Grey mould lesions on the inoculated leaves were reduced by the vapours from cinnamon oil, origanum oil and thyme oil at different levels, but fennel oil did not limit the spread of the necrotic lesions. Decreases in cuticle defect, lipid peroxidation, and hydrogen peroxide production in the B. cinerea-inoculated leaves were correlated with reduced lesions by the cinnamon oil vapours. The reduced lesions by the cinnamon oil vapour were well matched with arrested fungal proliferation on the inoculated leaves. The cinnamon oil vapour regulated tomato defence-related gene expression in the leaves with or without fungal inoculation. These results suggest that the plant essential oil vapours, notably cinnamon oil vapour, can provide eco-friendly alternatives to manage grey mould during tomato production.

Impacts of Dutch elm disease-causing fungi on foliage photosynthetic characteristics and volatiles in Ulmus species with different pathogen resistance

Global warming affects the abiotic and biotic growth environment of plants, including the spread of fungal diseases such as Dutch elm disease (DED). Dutch elm disease-resistance of different Ulmus species varies, but how this is reflected in leaf-level physiological pathogen responses has not been investigated. We studied the impacts of mechanical injury alone and mechanical injury plus inoculation with the DED-causing pathogens Ophiostoma novo-ulmi subsp. novo-ulmi and O. novo-ulmi subsp. americana on Ulmus glabra, a more vulnerable species, and U. laevis, a more resistant species. Plant stress responses were evaluated for 12 days after stress application by monitoring leaf net CO2 assimilation rate (A), stomatal conductance (gs), ratio of ambient to intercellular CO2 concentration (Ca/Ci) and intrinsic water-use efficiency (A/gs), and by measuring biogenic volatile (VOC) release by plant leaves. In U. glabra and U. laevis, A was not affected by time, stressors or their interaction. Only in U. glabra, gs and Ca/Ci decreased in time, yet recovered by the end of the experiment. Although the emission compositions were affected in both species, the stress treatments enhanced VOC emission rates only in U. laevis. In this species, mechanical injury especially when combined with the pathogens increased the emission of lipoxygenase pathway volatiles and dimethylallyl diphosphate and geranyl diphosphate pathway volatiles. In conclusion, the more resistant species U. laevis had a more stable photosynthesis, but stronger pathogen-elicited volatile response, especially after inoculation by O. novo-ulmi subsp. novo-ulmi. Thus, stronger activation of defenses might underlay higher DED-resistance in this species.

Co-treatment with Origanum Oil and Thyme Oil Vapours Synergistically Limits the Growth of Soil-borne Pathogens Causing Strawberry Diseases

Vapours from origanum oil (O) and thyme oil (T) were applied to the four soil-borne strawberry pathogens Fusarium oxysporum f. sp. fragariae, Colletotrichum fructicola, Lasiodiplodia theobromae, and Phytophthora cactorum, causing Fusarium wilt, anthracnose, dieback, and Phytophthora rot, respectively. Increasing T vapour doses in the presence of O vapour strongly inhibited mycelial growths of the four pathogens and vice versa. When mycelia of F. oxysporum f. sp. fragariae and P. cactorum exposed to the combined O + T vapours were transferred to the fresh media, mycelial growth was restored, indicating fungistasis by vapours. However, the mycelial growth of C. fructicola and L. theobromae exposed to the combined O + T vapours have been slightly retarded in the fresh media. Prolonged exposure of strawberry pathogens to O + T vapours in soil environments may be suggested as an alternative method for eco-friendly disease management.

Direct and Indirect Effects of Essential Oils for Sustainable Crop Protection

Plant essential oils (EOs) are gaining interest as biopesticides for crop protection. EOs have been recognized as important ingredients of plant protection products including insecticidal, acaricidal, fungicidal, and nematicidal agents. Considering the growing importance of EOs as active ingredients, the domestication and cultivation of Medicinal and Aromatic Plants (MAPs) to produce chemically stable EOs contributes to species conservation, provides the sustainability of production, and decreases the variations in the active ingredients. In addition to these direct effects on plant pests and diseases, EOs can induce plant defenses (priming effects) resulting in better protection. This aspect is of relevance considering that the EU framework aims to achieve the sustainable use of new plant protection products (PPPs), and since 2020, the use of contaminant PPPs has been prohibited. In this paper, we review the most updated information on the direct plant protection effects of EOs, focusing on their modes of action against insects, fungi, and nematodes, as well as the information available on EOs with plant defense priming effects.

Impact of Storage Condition on Chemical Composition and Antifungal Activity of Pomelo Extract against Colletotrichum gloeosporioides and Anthracnose in Post-harvest Mango

Anthracnose caused by Colletotrichum leads to a tremendous post-harvest mango loss. While chemical fungicides are applied to control anthracnose, natural alternatives are preferred due to food safety and environmental concerns. Pomelo extract (PE) exhibits a broad spectrum of antimicrobial activities; however, its effect against anthracnose is unknown. Here we investigated the chemical profile of PE using GC-MS and the anti-anthracnose activity of PE using in vitro and in vivo assays. We also evaluated the impact of storage temperature (0°, 5°, 10°, 20°, -20°, and -80 °C) and light conditions on the composition and antifungal activity of PE. We found that PE inhibited C. gloeosporioides in vitro with an IC₅₀ of 3.2 mL L^-1. Applying chitosan-based coating incorporated with 20 mL L^-1 PE significantly suppressed anthracnose in post-harvest 'Keitt' mango. A storage temperature below 5 °C substantially preserved major compounds and the antifungal activity of PE after 6 m of storage. Finally, we showed that applying d-limonene, the key constituent of PE, inhibited C. gloeosporioides in vitro (IC₅₀: 10.9 mM) and suppressed anthracnose in vivo. In conclusion, we demonstrated that the application of PE and d-limonene are sustainable methods for anthracnose control in post-harvest crops and established the preservation protocol for PE.

Floral Scents and Fruit Aromas: Functions, Compositions, Biosynthesis, and Regulation

Floral scents and fruit aromas are crucial volatile organic compounds (VOCs) in plants. They are used in defense mechanisms, along with mechanisms to attract pollinators and seed dispersers. In addition, they are economically important for the quality of crops, as well as quality in the perfume, cosmetics, food, drink, and pharmaceutical industries. Floral scents and fruit aromas share many volatile organic compounds in flowers and fruits. Volatile compounds are classified as terpenoids, phenylpropanoids/benzenoids, fatty acid derivatives, and amino acid derivatives. Many genes and transcription factors regulating the synthesis of volatiles have been discovered. In this review, we summarize recent progress in volatile function, composition, biosynthetic pathway, and metabolism regulation. We also discuss unresolved issues and research perspectives, providing insight into improvements and applications of plant VOCs.

Effects of Gum Arabic Coatings Enriched with Lemongrass Essential Oil and Pomegranate Peel Extract on Quality Maintenance of Pomegranate Whole Fruit and Arils

The effects of gum arabic coatings combined with lemongrass oil and/or pomegranate peel extract on freshly harvested mature 'Wonderful' pomegranate fruit were studied. Fruit were coated with gum arabic (GA) (1.5% w/v) alone or enriched with lemongrass oil (LM) (0.1% v/v) and/or pomegranate peel extract (PP) (1% w/v). Fruit were packed into standard open top ventilated cartons (dimensions: 0.40 m long, 0.30 m wide and 0.12 m high), and stored for 6 weeks at 5 ± 1 °C (90% RH). Evaluations were made every 2 weeks of cold storage and after 5 d of shelf life (20 °C and 65% RH). Fruit coated with GA + PP (4.09%) and GA + PP + LM (4.21%) coatings recorded the least cumulative weight loss compared to the uncoated control (9.87%). After 6 weeks, uncoated control and GA + PP + LM recorded the highest (24.55 mg CO2Kg-1h-1) and lowest (10.76 mg CO2Kg-1h-1) respiration rate, respectively. Coating treatments reduced the incidence of decay and treatments GA + LM + PP and GA + PP recorded the highest total flavonoid content between 2 and 6 weeks of storage. The findings suggest that GA coatings with/without LM and PP can be a beneficial postharvest treatment for 'Wonderful' pomegranates to reduce weight loss and decay development during cold storage.

Recent advances and future perspective of essential oils in control Colletotrichum spp.: A sustainable alternative in postharvest treatment of fruits

The world population growth has raised concerns about food security. Agricultural systems are asked to satisfy a growing demand for food with increasingly limited resources, and simultaneously still must reduce the impacts on the environment. This scenario encourages the search for safe and sustainable production strategies. Reducing losses in the production process can be one of the main ways to guarantee food safety. In fruticulture, it is estimated that more than 50% of the production can be lost between harvest and the final consumer due to postharvest diseases caused by phytopathogenic fungi. The fungi of the genus Colletotrichum are opportunistic and are associated with several diseases, being the anthracnose the most relevant in terms of the quality and yield losses in fruit species around worldwide. To control these diseases, the use of synthetic fungicides has been the main instrument utilized, however, because of their phytotoxicity to human health, the environment, and strong selection pressure imposed by continuous applications, the fungicides have caused resistance in the pathogen populations. So reducing the excessive application of these products is indispensable for human health and for sustainable Agriculture. Towards this purpose, research has been carried out to identify the phytopathological potentiality of essential oils (EOs) extracted from plants. Therefore, this review aims to contribute to the formation of knowledge bases, about the discoveries, recent advances, and the use of EOs as a strategy to alternatively control fungal disease caused by Colletotrichum spp. in postharvest fruits. Here, we provide valuable information exploring the application potential of essential oils as commercially useful biorational pesticides for food preservation, contributing to sustainable production and global food security.

Chemical profile and antifungal activity of plant extracts on Colletotrichum spp. isolated from fruits of Pimenta dioica (L.) Merr

Pimenta dioica (L.) Merr. is a popular seasoning species. During its production, there are losses of up to 50% due to anthracnose caused by fungi of the genus Colletotrichum. In this study, we evaluated the effect of ethanolic extracts on the in vitro and in vivo control of isolated Colletotrichum spp. Allspice. Extracts of leaves of P. dioica, Piper auritum, Plectranthus amboinicus and Psidium guajava were chemically characterized by gas chromatography and high performance liquid chromatography. Several monoterpenes, sesquiterpenes, flavonoids, organic acids, alkaloids and monoterpenoid phenols were identified among other organic compounds. Alpha-ocimene in P. dioica; alpha-thujene and isosafrole in P. auritum; kumatakenin, cirsilineol, taxifolin and retusin in P. amboinicus are reported for the first time. The extracts of P. amboinicus and P. dioica inhibited mycelial growth, spore germination in Colletotrichum spp. at concentrations of 5, 10 and 20 mg/mL, while the extracts of P. guajava and P. auritum did so at concentrations of 30 and 40 mg/mL. The extracts of P. amboinicus, P. dioica and P. auritum modified the size of the spores, caused degradation and formation of vacuoles in the spores of C. acutatum and C. gloeosporioides. The incidences in fruit inoculated with C. boninense and treated with the extracts of P. amboinicus and P. dioica were of 12% and 4% respectively. The severity was 1.5% with the extract of P. amboinicus and 0% with P. dioica. The results show the richness of bioactive compounds present in the extracts and their possible application to develop biotechnological products against phytopathogenic fungi.

Use of Essential Oils for the Control of Anthracnose Disease Caused by Colletotrichum acutatum on Post-Harvest Mangoes of Cat Hoa Loc Variety

Anthracnose disease caused by Colletotrichum spp. makes heavy losses for post-harvest mangoes of Cat Hoa Loc variety during storage, packaging, and transportation. The synthetic fungicides are commonly used to control the disease, but they are not safe for consumers’ health and environment. This study was aimed to investigate the use of essential oils (EOs) as the safe alternative control. Pathogen was isolated from the infected Cat Hoa Loc mangoes and identified by morphology and DNA sequencing of the ITS region. Six EOs (cinnamon, basil, lemongrass, peppermint, coriander, and orange) were chemically analyzed by GC–MS. The antifungal activity of EOs was studied in vitro and in vivo. The results showed that the isolated pathogen was Colletotrichum acutatum. Cinnamon, basil, and lemongrass EOs effectively inhibited the growth of C. acutatum in descending order of cinnamon, basil, and lemongrass. However, they (except basil oil) severely damaged fruit peels. The antifungal activity was closely related to the main compounds of EOs. Basil EOs effectively controlled anthracnose development on Cat Hoa Loc mangoes artificially infected with C. acutatum, and its effectiveness was comparable to that of fungicide treatment. Consequently, basil EOs can be used as a biocide to control anthracnose on post-harvest Cat Hoa Loc mangoes.

Actividad antifúngica in vitro del aceite esencial de Swinglea glutinosa Merr sobre Colletotrichum sp. patógeno de mango (Mangifera indica L.)

Se evaluó la actividad antifúngica del aceite esencial de limón de cerca (Swinglea glutinosa) sobre el hongo Colletotrichum sp. aislado de frutos de mango (Mangifera indica L). El aceite esencial, se obtuvo por hidrodestilación de hojas y corteza del fruto, y mediante cromatografía de gases acoplada a espectrometría de masas se determinó la fitoquímica. Se identificaron presuntivamente 41 metabolitos secundarios, siendo los compuestos mayoritarios β–pineno (31.3 %), α–pineno (15.1%) y germacreno D (14.4 %). El aceite esencial inhibió el crecimiento del hongo en un 31.16 %, 52.77 % y 82.41 % en ensayo de dilución en agar, a las concentraciones de 0.3, 1 y 2 % respectivamente, con diferencias entre todos los tratamientos evaluados (p=0.000). En ensayo de dilución en caldo se registró inhibición de la germinación de esporas de 0, 19.47, 41.03 y 100 % (p=0.000) a concentraciones de 0, 2, 4 y 8 µL/mL. Adicionalmente, en ensayo de microatmósfera se presentó una inhibición de máxima de 22,97 % del crecimiento micelial con adición de 20 µL de aceite esencial por caja de Petri (p=0.000). Este trabajo encontró que el aceite esencial de S. glutinosa ejerce inhibición dosis-dependiente sobre el crecimiento micelial y la germinación de esporas de Colletotrichum sp.

Activity of the Novel Fungicide Mefentrifluconazole Against Colletotrichum scovillei

The prevalence and destructiveness of anthracnose, caused by Colletotrichum scovillei, in pepper production regions seriously affects pepper yield and quality. Mefentrifluconazole, the first of the isopropanol-azole subgroup of triazole fungicides, was introduced for the control of pepper anthracnose. However, the growth characteristics of pepper fruit and rapid spread of anthracnose suggest that the fungicide application method must be optimized to enhance fungicide efficacy. The sensitivity of C. scovillei to mefentrifluconazole was determined by mycelial growth and germ tube elongation assays using 157 single-spore isolates with mean 50% effective concentration values of 0.462 ± 0.138 and 0.359 ± 0.263 mg/liter, respectively. The in vivo data also showed that mefentrifluconazole had favorable protective and curative effects against pepper anthracnose. Mefentrifluconazole significantly affected C. scovillei infection on pepper by reducing appressorium formation and sporulation, shriveling spores and germ tubes, and causing the abnormal development of appressoria and conidiophores. Mefentrifluconazole could move acropetally, horizontally, and basipetally in pepper plants. Compared with a knapsack sprayer, mefentrifluconazole applied by mist sprayer exhibited significantly better activity against pepper anthracnose. Additionally, as the spray volume increased from 45 to 150 liters/ha, the control efficacy of mefentrifluconazole first increased and then tended to be steady, with an optimal spray volume of 90 liters/ha. The difference in disease control efficacy was related to the deposition and droplet distribution of mefentrifluconazole on the pepper fruit. These results provide scientific guidance for the application of mefentrifluconazole in pepper fields and improved fungicide utilization.

The Use of Essential Oils from Thyme, Sage and Peppermint against Colletotrichum acutatum

The Colletotrichum spp. is a significant strawberry pathogen causing yield losses of up to 50%. The most common method to control plant diseases is through the use of chemical fungicides. The findings of plants antimicrobial activities, low toxicity, and biodegradability of essential oils (EO), make them suitable for biological protection against fungal pathogens. The aim is to evaluate the inhibition of Colletotrichum acutatum by thyme, sage, and peppermint EO in vitro on detached strawberry leaves and determine EO chemical composition. Our results revealed that the dominant compound of thyme was thymol 41.35%, peppermint: menthone 44.56%, sage: α,β-thujone 34.45%, and camphor: 20.46%. Thyme EO inhibited C. acutatum completely above 200 μL L^-1 concentration in vitro. Peppermint and sage EO reduced mycelial growth of C. acutatum. In addition, in vitro, results are promising for biological control. The detached strawberry leaves experiments showed that disease reduction 4 days after inoculation was 15.8% at 1000 μL L^-1 of peppermint EO and 5.3% at 800 μL L^-1 of thyme compared with control. Our findings could potentially help to manage C. acutatum; however, the detached strawberry leaves assay showed that EO efficacy was relatively low on tested concentrations and should be increased.

Melatonin Mitigates the Infection of Colletotrichum gloeosporioides via Modulation of the Chitinase Gene and Antioxidant Activity in Capsicum annuum L

Anthracnose, caused by Colletotrichum gloeosporioides, is one of the most damaging pepper (Capsicum annum L.) disease. Melatonin induces transcription of defense-related genes that enhance resistance to pathogens and mediate physiological activities in plants. To study whether the melatonin-mediated pathogen resistance is associated with chitinase gene (CaChiIII2), pepper plants and Arabidopsis seeds were treated with melatonin, then CaChiIII2 activation, hydrogen peroxide (H₂O₂) levels, and antioxidant enzymes activity during plant–pathogen interactions were investigated. Melatonin pretreatment uncoupled the knockdown of CaChiIII2 and transiently activated its expression level in both control and CaChiIII2-silenced pepper plants and enhanced plant resistance. Suppression of CaChiIII2 in pepper plants showed a significant decreased in the induction of defense-related genes and resistance to pathogens compared with control plants. Moreover, melatonin efficiently enabled plants to maintain intracellular H₂O₂ concentrations at steady-state levels and enhanced the activities of antioxidant enzymes, which possibly improved disease resistance. The activation of the chitinase gene CaChiIII2 in transgenic Arabidopsis lines was elevated under C. gloeosporioides infection and exhibited resistance through decreasing H₂O₂ biosynthesis and maintaining H₂O₂ at a steady-state level. Whereas melatonin primed CaChiIII2-overexpressed (OE) and wild-type (WT) Arabidopsis seedlings displayed a remarkable increase in root-length compared to the unprimed WT plants. Using an array of CaChiIII2 knockdown and OE, we found that melatonin efficiently induced CaChiIII2 and other pathogenesis-related genes expressions, responsible for the innate immunity response of pepper against anthracnose disease.

Activity of monoterpenoids on the in vitro growth of two Colletotrichum species and the mode of action on C. acutatum

Essential oils and their main compounds, monoterpenoids, are considered as alternative control systems for phytopathogenic fungi, particularly those related to late diseases of fruits and vegetables, like anthracnose caused by Colletotrichum species. In this context, we studied the effect of twenty monoterpenoids on Colletotrichum fructicola and C. acutatum to elucidate their effectiveness and mechanisms of action. Thus, we analyzed mycelial growth and conidial inhibitory concentration, as well as the effect of selected monoterpenoids on membrane integrity and cell vitality, reactive oxygen species (ROS) accumulation, and mitochondrial membrane potential by flow cytometry. The results showed that oxygenated monoterpenoids (alcohols and aldehydes) exhibited higher antifungal activity than their corresponding hydrocarbons, esters, and cyclic counterparts. Indicating that OH^- and O^- radicals react with cellular components affecting fungal homeostasis. In this sense, selected monoterpenoids (citral, citronellol, geraniol, carvacrol, and thymol) inhibited conidial germination of C. acutatum in a dose-dependent manner. The inhibition of conidial germination is associated with a loss of membrane integrity, a decrease of cell metabolism, and a dose-dependent accumulation of ROS, which was non-directly associated with modifications on mitochondrial membrane potential. Membrane dysfunction and ROS accumulation may be responsible for the necrotic behavior induced by high monoterpenoids concentrations, and possible apoptotic response in sub dosages of these compounds.

Chitinase Gene Positively Regulates Hypersensitive and Defense Responses of Pepper to Colletotrichum acutatum Infection

Anthracnose caused by Colletotrichum acutatum is one of the most devastating fungal diseases of pepper (Capsicum annuum L.). The utilization of chitin-binding proteins or chitinase genes is the best option to control this disease. A chitin-binding domain (CBD) has been shown to be crucial for the innate immunity of plants and activates the hypersensitive response (HR). The CaChiIII7 chitinase gene has been identified and isolated from pepper plants. CaChiIII7 has repeated CBDs that encode a chitinase enzyme that is transcriptionally stimulated by C. acutatum infection. The knockdown of CaChiIII7 in pepper plants confers increased hypersensitivity to C. acutatum, resulting in its proliferation in infected leaves and an attenuation of the defense response genes CaPR1, CaPR5, and SAR8.2 in the CaChiIII7-silenced pepper plants. Additionally, H₂O₂ accumulation, conductivity, proline biosynthesis, and root activity were distinctly reduced in CaChiIII7-silenced plants. Subcellular localization analyses indicated that the CaChiIII7 protein is located in the plasma membrane and cytoplasm of plant cells. The transient expression of CaChiIII7 increases the basal resistance to C. acutatum by significantly expressing several defense response genes and the HR in pepper leaves, accompanied by an induction of H₂O₂ biosynthesis. These findings demonstrate that CaChiIII7 plays a prominent role in plant defense in response to pathogen infection.

Chemical composition and biological activities of two chemotype-oils from Cinnamomum verum J. Presl growing in North Brazil

Chemical composition and antioxidant and antifungal action of the oils from leaves and wood bark of two chemotypes of Cinnamomum verum J. Presl were evaluated. Plants were sampled in the cities of São Luís and Santa Inês, state of Maranhão, Brazil. GC-MS and GC-FID, DPPH radical scavenging, and in vitro test against the phytopathogenic fungus Colletotrichum musae were used to perform these analyses. Cinnamomum verum is worldwide known as Cinnamon, highlighted for its extensive use in the cooking of diverse cultures of the world, and as a medicinal plant to treat environmental viral diseases. In the leaf oil of São Luís chemotype, eugenol (93.6%) was the main constituent, while in Santa Inês chemotype, it was benzyl benzoate (95.3%). In the bark wood oil of São Luís chemotype, (E)-cinnamaldehyde (89.3%) was the main constituent, while in Santa Inês chemotype, they were benzyl benzoate (23.3%), linalool (14.0%), (E)-caryophyllene (9.1%), caryolan-8-ol (7.2%) and borneol (4.7%). Leaf oils from both chemotypes showed strong to moderate antifungal activity, reaching 100% efficacy in eugenol-containing oils and above 70% in benzyl benzoate oils. In the antioxidant evaluation, the chemotype with a high eugenol content presented an inhibitory concentration higher than 80%, compared to Trolox. The leaf oils of the two C. verum chemotypes showed significant antifungal and antioxidant potential, considering their economic use as a functional and nutraceutical food supplement.

Chemical Composition of a Supercritical Fluid (Sfe-CO2) Extract from Baeckea frutescens L. Leaves and Its Bioactivity Against Two Pathogenic Fungi Isolated from the Tea Plant (Camellia sinensis (L.) O. Kuntze)

Colletotrichum gloeosporioides and Pseudopestalotiopsis camelliae-sinensis are the two most important tea plant (Camellia sinensis L.) pathogenic fungi. Interest in natural plant extracts as alternatives to synthetic chemical fungicides to control plant pathogens is growing. In this study, the volatile fraction of Baeckea frutescens L. was extracted by supercritical fluid extraction (SFE-CO₂), and its chemical composition was analyzed, and investigated for its antifungal activity against C. gloeosporioides and P. camelliae. The major constituents of the volatile fraction were β-caryophyllene (28.05%), α-caryophyllene (24.02%), δ-cadinene (6.29%) and eucalyptol (5.46%) in B. frutescens SFE-CO₂ extracts. The terpineol, linalool, terpinen-4-ol and eucalyptol showed strong contact antifungal activity against P. camelliae and C. gloeosporioides with median inhibitory concentration (MIC₅₀) in the range of 0.69 μL/mL to 2.79 μL/mL and 0.62 μL/mL to 2.18 μL/mL, respectively. Additionally, the volatile fraction had high fumigation antifungal activity against P. camelliae and C. gloeosporioides with an inhibition rate between 20.87% and 92.91%. Terpineol presented the highest antifungal activity in the contact and fumigation toxicity assays. Terpineol, linalool, terpinen-4-ol and eucalyptol were associated with the most active chemical compounds in the volatile fraction against the fungi. The results suggest that B. frutescens SFE-CO₂ extracts are potential ingredients to develop a natural fungicide for control of tea plant pathogens.

GC-MS analysis of volatiles in cinnamon essential oil extracted by different methods

Cinnamon essential oil (CEO) was extracted by three different methods: steam distillation (SD), ultrasound-assisted steam distillation (UASD) and microwave-assisted steam distillation (MASD). The volatiles in CEO were separated and identified by gas chromatography–mass spectrometry (GC-MS), and the differences in volatiles among the three different methods were further analyzed through principal component analysis. The results showed that 36 individual volatile components were present in the CEO from the three different methods. In general, the numbers of aldehydes, esters, alcohols, terpenes, aromatics and ketones were 6, 3, 7, 17, 2, and 1, respectively. The most abundant volatile component was determined to be cinnamic aldehyde. The content of total cinnamic aldehydes, which determines the price of CEO, was the highest among the three methods in the UASD sample (85.633%). Moreover, the highest yield (8.33‰) of essential oil was extracted by the UASD method. Therefore, UASD was the best way for CEO extraction in this research and was recommended for future industrial applications.

Preharvest and Postharvest Application of Garlic and Rosemary Essential Oils for Controlling Anthracnose and Quality Assessment of Strawberry Fruit During Cold Storage

This study assessed the feasibility of using essential oils (EOs) against Colletotrichum nymphaeae inciting strawberry anthracnose. Two EOs, extracted from Allium sativum (garlic) and Rosmarinus officinalis (rosemary), were selected because their fungicide efficacy was already well characterized under laboratory and greenhouse conditions. We characterized both EOs in terms of efficacy and impact on qualitative traits and sensory quality of strawberry fruit. The gas chromatography–mass spectrometry analysis confirmed the Diallyl trisulfide (29.08%) and (α)-pinene (15.779%) as the main components of A. sativum and R. officinalis EOs, respectively. Both A. sativum and R. officinalis EOs significantly inhibited the mycelial growth and conidial germination of C. nymphaeae in contact and vapor assays compared with untreated control. However, EC₅₀ assay indicated A. sativum EO was more effective than R. officinalis EO against the pathogen. Malformations of the vegetative structures of the pathogen exposed to both EOs were revealed as shriveled, collapsed, and swelling mycelia in the cultures. Both EOs confirmed their efficacy under in vivo and greenhouse conditions; in fact, they significantly reduced the development of fruit decay and anthracnose disease incidence and severity, compared with untreated controls. Both EOs preserved sensory attributes and quality parameters of strawberry fruit including firmness, total soluble solids, ascorbic acid, antioxidant activity, and anthocyanin, but may leave unwanted smells. These findings suggest that two EOs can potentially represent an alternative to synthetic chemical fungicides against C. nymphaeae preserving fruit quality factors, although their cost and the impact on the fruit odor must be carefully taken into consideration before developing a commercial product.

Management of Strawberry Anthracnose Using Plant Essential Oils as Bio-fungicides, and Evaluation of Their Effects on Quality of Strawberry Fruit

Colletotrichum nymphaeae is the causal agent of strawberry anthracnose, which is one of the most important disease affecting strawberry plant in Iran. This research aimed to apply the selected plant essential oils (EOs) such as Achillea millefolium, Mentha longifolia, and Ferula kuma to the management of strawberry anthracnose disease under in vitro, in vivo, and greenhouse conditions. In vitro tests indicated that all the EOs and fungicide were able to inhibit mycelial growth and conidial germination of the pathogen. Scanning electron microscopy (SEM) revealed that EOs significantly suppressed the mycelia growth and caused a change in morphology of fungal mycelia. The severity of strawberry anthracnose disease was significantly (p ≤ 0.05) reduced by all EOs under in vivo and greenhouse conditions. Results of all experiments showed that M. longifolia EO was the best EO to control C. nymphaeae. Also, EOs almost reduced weight loss and preserved firmness, ascorbic acid, total phenol, antioxidant activity (DPPH), and enzyme peroxidase activity in treated fruit. Moreover, EOs preserved the sensory quality of strawberry fruit during the storage period so that there were no significant differences between treatments (EOs) in their appearance, flavor, odor attributes, and overall evaluation compared to the control. Our results indicate that EOs are excellent bio-fungicides for the management of strawberry anthracnose.

Effect of Pyrisoxazole on Colletotrichum scovillei Infection and Anthracnose on Chili

Anthracnose caused by Colletotrichum scovillei is one of the most destructive diseases affecting chili production. Disease control mainly relies on conventional fungicides, and repeated exposure to single-site mode-of-action fungicides may pose a risk for the development of resistant isolates within the population. Our previous study suggested that pyrisoxazole has strong inhibitory activity against C. scovillei in vitro. However, the effects of pyrisoxazole on the C. scovillei infection process and the performance of pyrisoxazole in the field remain unclear. In this study, pyrisoxazole exhibited strong inhibitory activity against the mycelial growth, appressorium formation, and appressorium diameter of C. scovillei, with half maximal effective concentration values of 0.1986, 0.0147, and 0.0269 μg/ml, respectively, but had no effect on sporulation, even at the highest concentration of 1.6 μg/ml. The baseline sensitivity curves were unimodal with a long right-hand tail. The in vivo data showed that pyrisoxazole provided both preventive and curative activity against anthracnose on chili. Pyrisoxazole decreased the incidence of anthracnose and reduced disease progress. The results of electron microscopy showed that pyrisoxazole can affect the C. scovillei infection process by altering mycelial morphology, degrading conidia and germ tubes, suppressing conidial germination and appressorium formation, and enhancing conidiophore production. Pyrisoxazole can be used to effectively control anthracnose under field conditions and increase chili yield; moreover, no phytotoxicity symptoms were observed after treatment. These results provide new insight into the mechanisms by which pyrisoxazole controls disease and suggest that pyrisoxazole is a feasible alternative for the management of anthracnose in chili.

Fabrication of Antibacterial Nanofibrous Membrane Infused with Essential Oil Extracted from Tea Tree for Packaging Applications

Nanofibers made by electrospinning are being applied to an unlimited number of applications. In this paper, we propose the fabrication of antimicrobial functional nanofibers infused with essential oil for packaging applications that can extend the shelf-life of fruits. The morphology of nanofibers with different concentrations of essential oil was characterized by SEM and mechanical enhancement was confirmed via universal testing machine (UTM). The surface chemistry and crystalline of the nanofibers were investigated by FTIR and XRD, respectively. The CO₂ reduction study was carried out using a hand-made experimental apparatus and nanofiber hydrophobicity, which can prevent moisture penetration from the outside, was evaluated by contact angle. Antimicrobial properties of the functional nanofibers were estimated by using Gram-negative/positive bacteria. The cytotoxicity of the functional nanofibers was studied using fibroblast cells. Furthermore, this study investigated how long the shelf-life of tomatoes was extended. The nanofibers could serve as a multifunctional packaging, as an emerging technology in agricultural products, and even contribute to a better quality of various distributed agricultural products.

Antifungal Effects and Potential Mechanism of Essential Oils on Collelotrichum gloeosporioides In Vitro and In Vivo

The development of natural essential oil as an alternative to synthetic chemicals in the control of postharvest decay is currently in the spotlight. In the present study, the efficacy of seven essential oils in suppressing Collelotrichum gloeosporioides identified from sweet cherry was evaluated in vitro and clove oil was proved to be the most promising inhibitor. Thus, the antifungal properties and potential mechanisms of clove oil in vitro and in vivo by fumigation and contact treatments were intensively investigated. For C. gloeosporioides, the minimal inhibitory concentrations (MIC) of clove oil in air and contact phase were 80 and 300 μL/L in vitro testing, respectively. Based on the radial growth of C. gloeosporioides mycelium in medium, the fumgitoxic ability of essential oil was observed in a dose-dependent manner, which was not as dramatic as that under in vivo conditions. Furthermore, scanning electron microscopy and transmission electron microscopy of C. gloeosporioides exposed to clove oil exhibited obviously deleterious morphological and ultrastructural alterations confirming the disruption of fungal cell wall and endomembrane system, which resulted in increasing in permeability and causing the loss of intracellular constituents. In future, essential oils, combined with nano-emulsification approaches, could be good candidates as safe and effective antifungal agents for fungal spoilage of fresh commodities.

Antimildew Effects of Plectranthus amboinicus Leaf Essential Oil on Paper

In this study, we evaluated the antimildew effects on paper of Plectranthus amboinicus (Lour.) Spreng leaf essential oil prepared through hydrodistillation. The oil was isolated with a Clevenger-type apparatus and then characterized through gas chromatography with flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). A total of 43 compounds were identified, representing 99.5% of the oil. The main ingredients were carvacrol (50.0%), γ-terpinene (13.1%), and β-caryophyllene (11.3%). The leaf oil had excellent antimildew effects; its minimum inhibitory concentration (MIC) values against Aspergillus clavatus, A. niger, Cladosporium cladosporioides, Chaetomium globosum, Myrothecium verrucaria, Penicillium citrinum, and Trichoderma viride were 100, 200, 75, 75, 100, 150, and 150 μg/cm2 respectively. The leaf oil was further partitioned into 6 derivative fractions (PO1-PO6). PO2 had excellent antimildew effects on the abovementioned strains; at a concentration of 100 μg/cm2, all were 100% inhibited, except A. niger, which was 75.8% inhibited. Carvacrol, the main ingredient of PO2, was then isolated and used for antimildew tests; carvacrol had excellent antimildew activities. Since both P. amboinicus leaf essential oil and carvacrol were proved to have excellent antimildew effects on paper, they are worth further research and development.

Development, characterisation and efficacy evaluation of biochemical fungicidal formulations for postharvest control of anthracnose (Colletotrichum gloeosporioides Penz) disease in mango

The objectives of the study are to develop and characterise formulations with volatile molecules in an emulsifiable concentrate form, for their antimicrobial properties and to evaluate their efficacies against Colletotrichum gloeosporioides Penz., to control anthracnose in mangoes after harvest. Results showed EC39 and EC40 among formulations were characterised for their excellent emulsification properties, the droplet size of 192.34 ± 0.48 nm and 227.4 ± 0.71 nm and Zeta potential of -52.5 ± 2.76 mv and -48.84 ± 2.62 mv, respectively, with better storage stability at 10 ± 20 °C and RH 80 ± 5%. In vitro assay, 100% inhibition of visual spore germination by 0.15% and 0.2% MIC value for EC39 and EC40, respectively Studies on the efficacy of their fungicide properties also indicated the IC50 value of 0.161% and 0.162% for EC39 and EC40 respectively for mycelial growth inhibition. In vivo testing too, EC39 and EC40 effectively controlled anthracnose incidence in mango in a dosage-dependent manner.

Control of Anthracnose and Gray Mold in Pepper Plants Using Culture Extract of White-Rot Fungus and Active Compound Schizostatin

Fungi produce various secondary metabolites that have beneficial and harmful effects on other organisms. Those bioactive metabolites have been explored as potential medicinal and antimicrobial resources. However, the activities of the culture filtrate (CF) and metabolites of white-rot fungus (Schizophyllum commune) have been underexplored. In this study, we assayed the antimicrobial activities of CF obtained from white-rot fungus against various plant pathogens and evaluated its efficacy for controlling anthracnose and gray mold in pepper plants. The CF inhibited the mycelial growth of various fungal plant pathogens, but not of bacterial pathogens. Diluted concentrations of CF significantly suppressed the severity of anthracnose and gray mold in pepper fruits. Furthermore, the incidence of anthracnose in field conditions was reduced by treatment with a 12.5% dilution of CF. The active compound responsible for the antifungal and disease control activity was identified and verified as schizostatin. Our results indicate that the CF of white-rot fungus can be used as an eco-friendly natural product against fungal plant pathogens. Moreover, the compound, schizostatin could be used as a biochemical resource or precursor for development as a pesticide. To the best of our knowledge, this is the first report on the control of plant diseases using CF and active compound from white-rot fungus. We discussed the controversial antagonistic activity of schizostatin and believe that the CF of white-rot fungus or its active compound, schizostatin, could be used as a biochemical pesticide against fungal diseases such as anthracnose and gray mold in many vegetables.

Using Citrus aurantifolia essential oil for the potential biocontrol of Colocasia esculenta (taro) leaf blight caused by Phytophthora colocasiae

The aim of this work was to evaluate the antimicrobial activities of leaves and epicarp of Citrus aurantifolia essential oil against Phytophthora colocasiae, the causative agent of taro leaf blight. Oils were extracted by hydrodistillation, and their chemical composition was determined by gas chromatography and gas chromatography coupled with mass spectrometry. Antimicrobial activities of oils were tested in vitro against mycelium growth and sporangium production. In situ tests were done on healthy taro leaves, and the necrosis symptoms were evaluated. Results showed that the essential oil extraction yields from leaves and epicarp were 0.61 and 0.36%, respectively. Limonene (48.96%), bornyl acetate (14.18%), geraniol (10.53%), geranial (3.93%), and myrcene (3.14%) were the main components in leaf oil, while limonene (59.09%), cis-hydrate sabinene (7.53%), geranial (5.61%), myrtenol (5.02%), and terpinen-4-ol (3.48%) were the main components in epicarp oil. Both oils exhibited antimicrobial activities with total inhibition of the mycelium growth at 500 and 900 ppm for leaf and epicarp, respectively. The highest inhibitory concentration of sporangium production was 400 (72.84%) and 800 ppm (80.65%) for leaf and epicarp oil, respectively. For the standard fungicide (metalaxyl), the total inhibition value of mycelial growth and sporangium production was 750 ppm. In situ tests showed that, at 5000 ppm, total inhibition (100%) was obtained for a preventive test, while 50% of the inhibition was observed for a curative test when leaf oil was applied. When epicarp essential oil was applied at 5000 ppm, 47.5 and 16.66% of the reduction of leaf necrosis were observed for the preventive and curative test, respectively. There were positive correlations between both the oil concentration and the reduction of necrosis caused by P. colocasiae. These findings suggest that the C. aurantifolia essential oil could serve as an eco-friendly biocontrol for the management of taro leaf blight.

Functional characterization of the eugenol synthase gene (RcEGS1) in rose

The floral volatile compound eugenol is an important constituent in many aromatic plants, being a floral attractant for pollinators as well as having antimicrobial activity. Rose flowers emit eugenol and its derivatives. We recently reported a eugenol synthase gene (RcEGS1) (JQ522949) that was present in petals of R. chinensis cv. Old Blush. RcEGS1 has its highest expression levels in the petals compared to other tissues; it has higher transcript levels at the developmental blooming stage and lower levels at budding and senescence stages. Here, we overexpressed the RcEGS1 protein in Escherichia coli, and showed by Western-blot analysis that its expression was mainly detected in stamens and petals at the flower opening stage. RcEGS1 was principally localized in the upper and lower epidermal layers, which are the major sites of scent emission in roses. Furthermore, we demonstrated that down-regulation of RcEGS1 expression in flowers by virus-induced gene silencing led to a reduction of the relative content of eugenol. We suggested that RcEGS1 was responsible for eugenol biosynthesis in roses.

Toxicity and biochemical action of the antibiotic fungicide tetramycin on Colletotrichum scovillei

Tetramycin, a novel polyene macrolide antibiotic, has strong activity against a broad spectrum of fungi and may have potential uses in future agricultural applications. Thus, the antifungal activity and biochemical action of tetramycin on Colletotrichum scovillei were investigated in this study. The experimental results indicated that tetramycin had strong inhibitory activity against the mycelial growth, spore germination and germ tube elongation of C. scovillei. The baseline sensitivity curves were unimodal, with mean EC₅₀ values of 1.98 ± 0.078 μg/mL and 0.003 ± 0.005 μg/mL for mycelial growth and spore germination inhibition, respectively. Tetramycin also inhibited the germination of spores and formation of appressoria. After tetramycin treatment, the edge of the mycelial diaphragm showed protuberances, with decreased offshoots at the top. Additionally, disruption of the membrane was detected through an increase in membrane permeability, leakage of sugars and a reduction in the ergosterol content. Tetramycin effectively controlled C. scovillei on detached pepper fruits. These results will contribute to our evaluation of the potential of tetramycin for successful management of pepper anthracnose and to our understanding of the possible biochemical action of tetramycin against C. scovillei.

Differential Inhibitory Activities of Four Plant Essential Oils on In Vitro Growth of Fusarium oxysporum f. sp. fragariae Causing Fusarium Wilt in Strawberry Plants

The objective of this study was to determine inhibitory activities of four volatile plant essential oils (cinnamon oil, fennel oil, origanum oil and thyme oil) on in vitro growth of Fusarium oxysporum f. sp. fragariae causing Fusarium wilt of strawberry plants. Results showed that these essential oils inhibited in vitro conidial germination and mycelial growth of F. oxysporum f. sp. fragariae in a dose-dependent manner. Cinnamon oil was found to be most effective one in suppressing conidial germination while fennel oil, origanum oil and thyme oil showed moderate inhibition of conidial germination at similar levels. Cinnamon oil, origanum oil and thyme oil showed moderate antifungal activities against mycelial growth at similar levels while fennel oil had relatively lower antifungal activity against mycelial growth. Antifungal effects of these four plant essential oils in different combinations on in vitro fungal growth were also evaluated. These essential oils demonstrated synergistic antifungal activities against conidial germination and mycelial growth of F. oxysporum f. sp. fragariae in vitro. Simultaneous application of origanum oil and thyme oil enhanced their antimicrobial activities against conidial germination and fungal mycelial growth. These results underpin that volatile plant essential oils could be used in eco-friendly integrated disease management of Fusarium wilt in strawberry fields.

Potential Applications and Antifungal Activities of Engineered Nanomaterials against Gray Mold Disease Agent Botrytis cinerea on Rose Petals

Nanoparticles (NPs) have great potential for use in the fields of biomedicine, building materials, and environmental protection because of their antibacterial properties. However, there are few reports regarding the antifungal activities of NPs on plants. In this study, we evaluated the antifungal roles of NPs against Botrytis cinerea, which is a notorious worldwide fungal pathogen. Three common carbon nanomaterials, multi-walled carbon nanotubes, fullerene, and reduced graphene oxide, and three commercial metal oxidant NPs, copper oxide (CuO) NPs, ferric oxide (Fe2O3) NPs, and titanium oxides (TiO2) NPs, were independently added to water-agar plates at 50 and 200-mg/L concentrations. Detached rose petals were inoculated with spores of B. cinerea and co-cultured with each of the six nanomaterials. The sizes of the lesions on infected rose petals were measured at 72 h after inoculation, and the growth of fungi on the rose petals was observed by scanning electron microscopy. The six NPs inhibited the growth of B. cinerea, but different concentrations had different effects: 50 mg/L of fullerene and CuO NPs showed the strongest antifungal properties among the treatments, while 200 mg/L of CuO and Fe2O3 showed no significant antifungal activities. Thus, NPs may have antifungal activities that prevent B. cinerea infections in plants, and they could be used as antifungal agents during the growth and post-harvesting of roses and other flowers.

Differential Control Efficacies of Vitamin Treatments against Bacterial Wilt and Grey Mould Diseases in Tomato Plants

Bacterial wilt and grey mould in tomato plants are economically destructive bacterial and fungal diseases caused by Ralstonia solanacearum and Botrytis cinerea, respectively. Various approaches including chemical and biological controls have been attempted to arrest the tomato diseases so far. In this study, in vitro growths of bacterial R. solanacearum and fungal B. cinerea were evaluated using four different vitamins including thiamine (vitamin B1), niacin (vitamin B3), pyridoxine (vitamin B6), and menadione (vitamin K3). In planta efficacies of the four vitamin treatments on tomato protection against both diseases were also demonstrated. All four vitamins showed different in vitro antibacterial activities against R. solanacearum in dose-dependent manners. However, treatment with 2 mM thiamine was only effective in reducing bacterial wilt of detached tomato leaves without phytotoxicity under lower disease pressure (106 colony-forming unit [cfu]/ml). Treatment with the vitamins also differentially reduced in vitro conidial germination and mycelial growth of B. cinerea. The four vitamins slightly reduced the conidial germination, and thiamine, pyridoxine and menadione inhibited the mycelial growth of B. cinerea. Menadione began to drastically suppress the conidial germination and mycelial growth by 5 and 0.5 mM, respectively. Grey mould symptoms on the inoculated tomato leaves were significantly reduced by pyridoxine and menadione pretreatments one day prior to the fungal challenge inoculation. These findings suggest that disease-specific vitamin treatment will be integrated for eco-friendly management of tomato bacterial wilt and grey mould.