The European Union is promoting regulatory changes to ban fungicides because of the impact their use has on the ecosystem and the adverse effects they can pose for humans. An ecofriendly alternative ...to these chemicals to fight against fungal species with low toxicity is essential oils and their compounds extracted from aromatic plants. The purpose of this study was to evaluate the in vitro antifungal capacity of the botanical compounds eugenol, carvacrol, thymol, and cinnamaldehyde, and the synergy or antagonism of their mixtures, against
and
. Different bioassays were performed at doses of 300, 200, 150, and 100 µg/mL using pure commercial compounds and their combination in potato dextrose agar culture medium. Growth rate and the mycelium growth inhibition parameters were calculated. Phenolic compounds and their combination inhibited the development of species at the different concentrations, with fungicidal or fungistatic activity shown under almost all the tested conditions. When comparing the growth rates of the species in the control plates and treatments, the statistical analysis showed that there were statistically significant differences. The mixture of compounds improved fungicidal activity against the studied species and at a lower concentration of monoterpenes.
Fungal pathogens cause major yield losses in agriculture and reduce food quality and production worldwide.
To evaluate new safer alternatives to chemicals for disease management and preserve the ...shelf life of food, this research was conducted to: determine the chemical composition of the essential oils (EOs) of
and
chemotypes 1 and 2; investigate the antifungal potential of EOs
against:
,
,
,
f. sp.
,
,
; evaluate a natural
extract biofilm to conserve rice grain and cherry tomatoes.
EOs were analyzed by GC-MS+GC-FID. EOs' antifungal activity was evaluated by dissolving
extracts in PDA. Petri dishes were inoculated with disks of each fungus and incubated at 25°C for 7 days.
The
EO displayed the best Mycelial Growth Inhibition. The antifungal effect of the
EO biofilm was evaluated on rice caryopsis. Disinfected grains were dipped in a conidial suspension of each fungus and sprayed with EO (300 and 600 μg/mL) prepared in Tween 20. Grains were stored. The percentage of infected grains was recorded for 30 days. The
EO effect on cherry tomato conservation was evaluated
. Wounded fruit were immersed in the
EO (300 and 400 μg/mL) and inoculated with
f. sp.
. Fruit were evaluated for 7 and 14 days. Chemical profiles thymol/carvacrol for
, carvacrol for
Tp1 and thymol for
Tp2 were defined. The three evaluated EOs reduced all the studied phytopathogens' fungal growth. The
biofilm was effective with rice storage and against
f. sp.
for extending the shelf life of tomatoes in warehouses and storing postharvest cherry tomatoes.
We suggest applying these EOs as biofilms for safe food conservation to replace synthetic products.
The postharvest life of most fruit, vegetables and cereals is limited by fungal proliferation. The chemical composition of Mentha piperita, M. spicata and M. suaveolens essential oils (EO), and the ...antifungal activity against four pathogenic and post-harvest fungi isolated from food, were herein investigated to evaluate their potential as natural food preservatives. The EO were obtained by hydrodistillation of aerial parts leaves, stems and inflorescences (except for peppermint oil, which was purchased in a specialized store) and submitted to GC-MS and GC-FID analysis. Regarding the EO composition, carvone (41.1%) and limonene (14.1%) were the major compounds in M. spicata, menthol (47.0%) and menthone (23.1%), as well as other menthol derivatives (neomenthol -3.6%- and menthofurane -3.7%-) in M. piperita, and piperitone oxide (40.2%) and piperitenone oxide (31.4%) in M. suaveolens. Botryotinia fuckeliana was the most sensitive fungus. The three studied EO inhibited growth by 92–100%. The highest dose of M. suaveolens EO, 400 µg/mL, produced 100% MGI in all the studied fungi, except Fusarium oxysporum with 94.21%. The M. suaveolens EO can be considered to develop a low-risk enviro-friendly botanical biofungicide.
Fusarium sudanense is a novel fungus recently isolated from asymptomatic samples of wheat grains in Argentina. The fungus caused symptoms of seedling blight and seed rot on wheat after artificial ...inoculations. It is known that the production of mycotoxins by pathogens belonging to the Fusarium genus is harmful to human and animal health. Moreover, the warm and humid conditions that are favorable for growth and mycotoxin production of these species put the Argentinian wheat production area at a high risk of mycotoxin contamination with this novel pathogen. The aim of this work was to evaluate the antagonistic effect of Trichoderma harzianum against F. sudanense under in vitro tests at different environmental conditions. Fungi were screened in dual culture at different water activities (αw) (0.995, 0.98, 0.95, and 0.90) and temperatures (25 and 15 °C). The growth rate of the fungi, interaction types, and dominance index were evaluated. Also, the interaction between T. harzianum and F. sudanense was examined by light and cryo-scanning microscopy. T. harzianum suppressed the growth of F. sudanense at 0.995, 0.98, and 0.95 αw at 25 °C and 0.995 and 0.98 αw at 15 °C. Macroscopic study revealed different interaction types between F. sudanense and T. harzianum on dual culture. Dominance on contact where the colonies of T. harzianum overgrew the pathogen was the most common interaction type determined. The competitive capacity of T. harzianum was diminished by decreasing the temperature and αw. At 0.95 αw and 15 °C, both fungi grew slowly, and interaction type “A” was assigned. Microscopic analysis from the interaction zone of dual cultures revealed an attachment of T. harzianum to the F. sudanense hyphae, penetration with or without formation of appressorium-like structures, coiling, plasmolysis, and a veil formation. According to our results, T. harzianum demonstrated capability to antagonize F. sudanense and could be a promising biocontrol agent.
The chemical composition of Essential Oils Satureja montana and Mentha longifolia was determined, and their activity against important phytopathogenic and post-harvest fungi was studied, to evaluate ...their potential as natural food preservatives. The major compounds were carvacrol (24.0%), γ-terpinene (15.9%) and p-cymene (14.2%) in S. montana, and piperitenone oxide (52.7%) and piperitone oxide (23.5%) in M. longifolia. EOs were tested in vitro on Alternaria alternata, Botryotinia fuckeliana, Curvularia hawaiiensis, Fusarium equiseti, F. oxysporum lycopersici, Rhizoctonia solani and Verticillium dahliae. S. montana demonstrated excellent results. At 300 μg mL−1 the growth of all fungi was inhibited with 100% mycelial growth inhibition (MGI), except for B. fuckeliana (92%). M. longifolia was less effective, and its best result was against Verticillium dahliae (100% MGI) at 400 and 300 μg mL−1. S. montana EO was selected for in vivo antifungal tests in Cherry tomatoes and kaki “Persimmon” against A. alternata. The S. montana EO biofilm reduced post-harvest fungi development. In tomato, it inhibited up to 90% after 20 days. Necrosis did not occur for 2 months in the persimmon fruits. S. montana EO is an effective non-toxic preservative that can be considered to develop a botanical and enviro-friendly low-risk biofungicide.
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•Satureja montana and Mentha longifolia EOs were tested as food preservatives.•The in vitro tested Satureja montana EO showed great antifungal activity.•A natural biodegradable Satureja montana EO biofilm was developed.•The S. montana EO biofilm controlled Alternaria alternata in tomato and kaki.•The composition of the EOs was determined by CG and GC/MS.
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An endophytic fungus isolated from healthy wheat seeds cultivar Klein Yarará in Buenos Aires Province, Argentina, was initially identified as belonging to the Fusarium fujikuroi ...species complex based on morphological and cultural characteristics. The fungus role in pathogenicity was investigated by artificial inoculation of wheat seeds. Symptoms evaluated 7 and 14 days after inoculation showed that the fungus was pathogenic on seed and seedlings causing symptoms as seed decay, seedling blight and seed rot. The fungus was re-isolated to fulfill Koch’s Postulates and was identified as F. sudanense (strain LBEA 3100), a new species recorded in Argentina. The fungal identity was corroborated using molecular techniques by sequencing the ITS region, D1/D2 domains of the LSU gene and TEF-1 alpha region and by comparison with international databases. Ecophysiological studies of F. sudanense (LBEA 3100) performed at different water activities and temperatures showed faster growth rate at the highest water activity and 25 °C. This is the first report of F. sudanense, isolated from healthy wheat seeds, causing typical symptoms of seedling blight and seed rot on wheat.
Films based on starch-gellan blends at 9:1 and 8:2 ratios containing emulsified or lecithin encapsulated thyme (Thymus zygis) essential oil (EO) (0.25 or 0.5 g/g polymer), were obtained by casting ...method and characterized as to their structural, functional (mechanical, barrier and optical) and in vitro antifungal properties against Alternaria alternata (AA) and Botryotinia fuckeliana (BF). The EO retention during the film formation was also quantified. Lecithin encapsulation of the EO allowed for greater oil retention (45–55%), which enhanced the antifungal activity of the films, which were more effective against BF than AA. All films exhibited high oxygen barrier capacity, while lecithin improved the films water barrier properties and gloss, conferring them with a slightly brownish color. Lecithin also reduced the film stiffness and resistance to break and extensibility. Of the studied formulations, 8:2 S:G films with lecithin-encapsulated EO were very effective at controlling fungal growth, while exhibiting adequate functional properties as packaging/coating materials.
•Starch-gellan films showed antifungal activity dependent on the essential oil content.•Free or lecithin encapsulated oil changed the film structure and functionality.•Lecithin encapsulation greatly improved the essential oil retention in the films.•Botryotinia fuckeliana was more sensitive than Alternaria alternata to the active films.
The chemical composition of commercial Syzygium aromaticum, Cinnamomum verum, and Laurus nobilis essential oils as well as their antifungal activity against four pathogenic fungi isolated from ...Mediterranean rice grains has been investigated. Eighty nine compounds accounting for between 98.5 and 99.4% of the total essential oil were identified. The phenylpropanoids eugenol (89.37 ± 0.29%) and eugenol (56.34 ± 0.41%), followed by eugenol acetate (19.48 ± 0.13%) were, respectively, the main compounds in clove and cinnamon essential oils, whereas large amounts of the oxygenated monoterpenes 1,8-cineole (58.07 ± 0.83%) and α-terpinyl acetate (13.05 ± 0.44%) were found in bay leaf essential oil. Clove and cinnamon oils showed the best antifungal activity results against all tested fungi. Against Alternaria alternata, clove essential oil displayed the best antifungal effect, whereas against Curvularia hawaiiensis, cinnamon essential oil was more active. Both essential oils showed a similar antifungal effect towards Fusarium proliferatum and Fusarium oxysporum. In vitro studies in inoculated rice grains showed that clove and cinnamon totally inhibited pathogenic fungal development after 30 days of incubation. In vivo studies showed that eugenol used with a polysaccharide such as agar–agar formed a fine coat which wraps the inoculated rice grains, creating a natural biofilm and reducing the development of all pathogenic fungi (80–95%) for 30 days.
Aloe vera gel, analysed as to its antifungal properties against six fungi causing plant diseases, was found to be most effective against Fusarium oxysporum. It was included in different ratios in ...starch based films plastiziced with glycerol to obtain antifungal films. These were characterized as to their physical (barrier and optical) and structural properties. Films containing the highest ratio of Aloe vera solids (1:1, with respect to starch) and different glycerol mass ratios with respect to starch (0.15 and 0.25) were analysed as to the water sorption and water plasticization effects, in order to discover the water sensitivity of the films in different RH ambients. Films with 0.15 g glycerol/g starch were more homogenous, with a lower degree of starch crystallization, reduced water vapour permeability and higher gloss and transparency. These films with the highest Aloe vera ratio were effective at controlling fungal decay and weight loss in cherry tomatoes.
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•Aloe vera gel was effective against Fusarium oxysporum.•Aloe vera could be effectively incorporated into starch matrices to obtain coatings.•Coatings with Aloe vera were effective at controlling fungal decay in tomatoes.
The postharvest life of most fruit and vegetables is limited by fungus proliferation. The Aloe vera gel was added at different concentrations to test its antifungal potential against five fungi ...(Rhizoctonia solani, Curvularia hawaiiensis, Botryotinia fuckeliana, Penicillium italicum, Verticillium dahliae), which cause significant losses in basic agricultural products included in the world's diet: tuber potato, cereals, fruit and vegetables. The best results were for the fungus Verticillium dahlie, with a mycelial growth inhibition of 100% and 70% at 200 and 100 mL/L, respectively. Satisfying results were for fungi R. solani and B. fuckeliana, where the mycelial growth inhibition exceeded 50% in them all at 200 mL/L. Antifungal activity was maintained in B. fuckeliana by lowering the dose to 100 mL/L. The Aloe vera extract at 300 mL/L was applied as a coating in the postharvest treatment to blueberry fruit at 21 °C and 85% humidity. When the experiment ended, the percentage of rotted berries was significantly lower in the treated than in the control. The Aloe vera gel could be considered a promising postharvest treatment to maintain blueberry quality and turgor during storage.
•Aloe vera leaf extract inhibited postharvest fungi in a dose-dependent manner.•Verticillium dahliae had the best results with total inhibition of mycelial growth.•Antifungal activity was maintained in B. fuckeliana by lowering the dose.•The natural film created extended shelf life and maintained blueberry quality.
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