In vitro Varietal Screening for Resistance to Aspergillus Flavus Invasion and Aflatoxin Production in Groundnut

Controlling proliferation and aflatoxin production by Aspergillus flavus is a pressing challenge for global food safety and security. Marine bacterium Staphylococcus saprophyticus strain L-38 showed excellent antifungal activity toward A. flavus in vitro and in vivo. In sealed, non-contact confrontation assays, L-38 completely inhibited conidial germination and mycelial growth of A. flavus through the production of volatile organic compounds (VOCs). Gas chromatography-mass spectrometry identified 3,3-dimethyl-1,2-epoxybutane (3-DE) as the most abundant VOC (32.61% of total peak area, 78% matching). Exposure of A. flavus cultures to synthetic 3-DE similarly demonstrated strong inhibition of growth. Moreover, culture of L-38 in a sealed chamber with maize or peanuts artificially inoculated with A. flavus, at high water activity, resulted in significant inhibition of A. flavus germination and aflatoxin biosynthesis. Scanning electron microscopy of these samples revealed severe damage to conidial cells and hyphae compared to samples not exposed to L-38. L-38 also showed broad and effective antifungal activity toward eight other phytopathogenic fungi including Aspergillus niger, Fusarium verticillioides, Fusarium graminearum, Sclerotinia sclerotiorum, Rhizoctonia solani, Alternaria alternata, Monilinia fructicola, and Botrytis cinerea. This work introduces S. saprophyticus L-38 as a potential biocontrol agent and demonstrates the efficacy of the volatile 3-DE in the control of A. flavus and other destructive plant pathogens for post-harvest food safety.

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Rice Phyllosphere Bacillus Species and Their Secreted Metabolites Suppress Aspergillus flavus Growth and Aflatoxin Production In Vitro and In Maize Seeds

Toxins ◽

10.3390/toxins10040159 ◽

2018 ◽

Vol 10 (4) ◽

pp. 159 ◽

Cited By ~ 4

Author(s):

Subbaiah Chalivendra ◽

Catherine DeRobertis ◽

Jorge Reyes Pineda ◽

Jong Ham ◽

Kenneth Damann

Keyword(s):

Aspergillus Flavus ◽

Aflatoxin Production ◽

Bacillus Species ◽

Maize Seeds

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Assessment of the Effect of Satureja montana and Origanum virens Essential Oils on Aspergillus flavus Growth and Aflatoxin Production at Different Water Activities

Toxins ◽

10.3390/toxins12030142 ◽

2020 ◽

Vol 12 (3) ◽

pp. 142 ◽

Cited By ~ 3

Author(s):

Marta García-Díaz ◽

Jessica Gil-Serna ◽

Belén Patiño ◽

Esther García-Cela ◽

Naresh Magan ◽

...

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Aspergillus Flavus ◽

Aflatoxin Production ◽

Aflatoxin Contamination ◽

Activity Levels ◽

Control Methods ◽

Mycotoxin Biosynthesis ◽

Satureja Montana

Aflatoxin contamination of foodstuffs poses a serious risk to food security, and it is essential to search for new control methods to prevent these toxins entering the food chain. Several essential oils are able to reduce the growth and mycotoxin biosynthesis of toxigenic species, although their efficiency is strongly influenced by the environmental conditions. In this work, the effectiveness of Satureja montana and Origanum virens essential oils to control Aspergillus flavus growth was evaluated under three water activity levels (0.94, 0.96 and 0.98 aw) using a Bioscreen C, a rapid in vitro spectrophotometric technique. The aflatoxin concentrations at all conditions tested were determined by HPLC-FLD. Aspergillus flavus growth was delayed by both essential oil treatments. However, only S. montana essential oil was able to significantly affect aflatoxin production, although the inhibition percentages widely differed among water activities. The most significant reduction was observed at 0.96 aw, which is coincident with the conditions in which A. flavus reached the highest levels of aflatoxin production. On the contrary, the treatment with S. montana essential oil was not effective in significantly reducing aflatoxin production at 0.94 aw. Therefore, it is important to study the interaction of the new control compounds with environmental factors before their application in food matrices, and in vitro ecophysiological studies are a good option since they provide accurate and rapid results.

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Aspergillus flavus NRRL 3251 Growth, Oxidative Status, and Aflatoxins Production Ability In Vitro under Different Illumination Regimes

Toxins ◽

10.3390/toxins10120528 ◽

2018 ◽

Vol 10 (12) ◽

pp. 528 ◽

Cited By ~ 5

Author(s):

Tihomir Kovač ◽

Bojan Šarkanj ◽

Biljana Crevar ◽

Marija Kovač ◽

Ante Lončarić ◽

...

Keyword(s):

Aspergillus Flavus ◽

Growth Period ◽

Aflatoxin Production ◽

Aflatoxin Contamination ◽

Oxidative Status ◽

Light Illumination ◽

Proper Understanding ◽

Experimental Strains ◽

Oxidative Species

Aspergillus flavus is the most important mycotoxin-producing fungus involved in the global episodes of aflatoxin B1 contamination of crops at both the pre-harvest and post-harvest stages. However, in order to effectively control aflatoxin contamination in crops using antiaflatoxigenic and/or antifungal compounds, some of which are photosensitive, a proper understanding of the photo-sensitive physiology of potential experimental strains need to be documented. The purpose of the study is therefore to evaluate the effect of visible (VIS) light illumination on growth and conidiation, aflatoxin production ability and modulation of A. flavus oxidative status during in vitro experiment. Aflatoxigenic A. flavus strain was inoculated in aflatoxin-inducing YES media and incubated under three different VIS illumination regimes during a 168 h growth period at 29 °C. VIS illumination reduced A. flavus mycelia biomass yield, both during growth on plates and in liquid media, promoted conidiation and increased the aflatoxin production. Furthermore, aflatoxin production increased with increased reactive oxidative species (ROS) levels at 96 h of growth, confirming illumination-driven oxidative stress modulation activity on A. flavus cells.

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Use of Natural Products on the Control of Aspergillus flavus and Production of Aflatoxins In Vitro and on Tomato Fruit

Plants ◽

10.3390/plants10122553 ◽

2021 ◽

Vol 10 (12) ◽

pp. 2553

Author(s):

Mario Alberto Segura-Palacios ◽

Zormy Nacary Correa-Pacheco ◽

Maria Luisa Corona-Rangel ◽

Ollin Celeste Martinez-Ramirez ◽

Dolores Azucena Salazar-Piña ◽

...

Keyword(s):

Natural Products ◽

Aspergillus Flavus ◽

Mycelial Growth ◽

Disease Incidence ◽

Tomato Fruit ◽

Aflatoxin Production ◽

Vegetable Products ◽

Citrus Seed ◽

Resin Extract

Aspergillus flavus affects fresh and dry fruit and vegetable products, and its toxic metabolites, namely aflatoxins, cause serious damage in humans. The objective of this research study was to evaluate the effect of commercial natural products as well as edible and nanostructured chitosan coatings on the development of A. flavus and on the production of aflatoxins in vitro and in tomato. Treatments were as follows: chitosan 1%, chitosan coating, chitosan nanostructured coating, Citrocover 1% (citrus seed extract), Resinadher 0.5% (pine resin extract), mancozeb 2%, and water. The variables were as follows: halo inhibition, spore production, and aflatoxins content. In fruit, the following were evaluated: disease incidence, mycelial growth, and aflatoxin production. An ANOVA (Tukey: p < 0.05) was used. In vitro results showed that Citrocover and Resinadher reduced sporulation (0.2 and 0.9 × 105 spores mL−1, respectively), while chitosan inhibited the production of aflatoxins. With Resinadher and Citrocover, tomato fruit had the lowest incidence, mycelial growth, and aflatoxin production with corresponding values of 0%, 0.0 cm2, and 0.95 ppb, respectively, and 7%, 0.2 cm2, and 1.77 ppb, respectively. The use of Citrocover and Resinadher could be a viable alternative to decrease the development of A. flavus in tomato fruit.

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Triadimenol stimulates aflatoxin production by Aspergillus flavus in vitro

Mycological Research ◽

10.1016/s0953-7562(09)81327-0 ◽

1990 ◽

Vol 94 (8) ◽

pp. 1023-1025 ◽

Cited By ~ 5

Author(s):

P. Bayman ◽

P.J. Cotty

Keyword(s):

Aspergillus Flavus ◽

Aflatoxin Production

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Activity and Anti-Aflatoxigenic Effect of Indigenously Characterized Probiotic Lactobacilli against Aspergillus flavus—A Common Poultry Feed Contaminant

Animals ◽

10.3390/ani9040166 ◽

2019 ◽

Vol 9 (4) ◽

pp. 166 ◽

Cited By ~ 2

Author(s):

Nimra Azeem ◽

Muhammad Nawaz ◽

Aftab Ahmad Anjum ◽

Shagufta Saeed ◽

Saba Sana ◽

...

Keyword(s):

Aspergillus Flavus ◽

High Performance ◽

Animal Feed ◽

Aflatoxin Production ◽

Aflatoxin Contamination ◽

Poultry Feed ◽

Poultry Production ◽

Ameliorative Effect ◽

Probiotic Lactobacilli

Aflatoxin contamination in human food and animal feed is a threat to public safety. Aflatoxin B1 (AFB1) can be especially damaging to poultry production and consequently economic development of Pakistan. The present study assessed the in vitro binding of AFB1 by indigenously characterized probiotic lactobacilli. Six isolates (Lactobacillus gallinarum PDP 10, Lactobacillus reuetri FYP 38, Lactobacillus fermentum PDP 24, Lactobacillus gallinarum PL 53, Lactobacillus paracasei PL 120, and Lactobacillus gallinarum PL 149) were tested for activity against toxigenic Aspergillus flavus W-7.1 (AFB1 producer) by well diffusion assay. Only three isolates (PL 53, PL 120, and PL 149) had activity against A. flavus W-7.1. The ameliorative effect of these probiotic isolates on AFB1 production was determined by co-culturing fungus with lactobacilli for 12 days, followed by aflatoxin quantification by high-performance liquid chromatography. In vitro AFB1 binding capacities of lactobacilli were determined by their incubation with a standard amount of AFB1 in phosphate buffer saline at 37 °C for 2 h. AFB1 binding capacities of isolates ranged from 28–65%. Four isolates (PDP 10, PDP 24, PL 120, and PL 149) also ceased aflatoxin production completely, whereas PL 53 showed 55% reduction in AFB1 production as compared to control. The present study demonstrated Lactobacillus gallinarum PL 149 to be an effective candidate AFB1 binding agent against Aspergillus flavus. These findings further support the binding ability of lactic acid bacteria for dietary contaminants.

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Aspergillus flavus and Aflatoxin Contamination of Leguminous Trees of the Sonoran Desert in Arizona

Phytopathology ◽

10.1094/phyto.2001.91.9.913 ◽

2001 ◽

Vol 91 (9) ◽

pp. 913-919 ◽

Cited By ~ 28

Author(s):

María L. Boyd ◽

Peter J. Cotty

Keyword(s):

Aspergillus Flavus ◽

Sonoran Desert ◽

Aflatoxin Production ◽

Common Species ◽

Aflatoxin Contamination ◽

Leguminous Trees ◽

Significant Growth ◽

Tree Legumes ◽

Aflatoxin B

Aspergillus spp. in section Flavi were frequently associated with desert tree legumes in uncultivated areas of the Sonoran Desert. Of 270 samples of debris and fruits of mesquite (Prosopis spp.), ironwood (Olneya tesota), acacia (Acacia spp.), and palo verde (Cercidium and Parkinsonia spp.), 87% were positive for A. flavus (S and L strains) and A. tamarii. A. flavus was the most common species (87%) among the 3,763 isolates examined. Mesquite pods were both the substrate from which A. flavus was recovered most frequently and the substrate from native habitats with the greatest aflatoxin content. In vitro, most desert legumes supported significant growth, reproduction, and aflatoxin production by A. flavus, with mesquite pods yielding 1 × 1010 propagules/g and 5,000 μg/kg of aflatoxin B1. Twenty percent of legume pods collected in the desert contained measurable quantities of aflatoxin, ranging from 1 to >2,500 μg/kg. Insect-damaged mesquite pods had significantly higher aflatoxin than intact pods. Legumes are apparently important reservoirs of aflatoxin-producing fungi and significant sources of aflatoxin contamination in the native Sonoran Desert habitats of Arizona.

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Genetic diversity in Aspergillus flavus: association with aflatoxin production and morphology

Canadian Journal of Botany ◽

10.1139/b93-003 ◽

1993 ◽

Vol 71 (1) ◽

pp. 23-31 ◽

Cited By ~ 123

Author(s):

Paul Bayman ◽

Peter J. Cotty

Keyword(s):

Aspergillus Flavus ◽

Random Amplified Polymorphic Dna ◽

Geographic Origin ◽

Cladistic Analysis ◽

Dna Amplification ◽

Aflatoxin Production ◽

Vegetative Compatibility ◽

Dna Polymorphisms ◽

Vegetative Compatibility Groups

Isolates of Aspergillus flavus belonging to at least 12 vegetative compatibility groups were characterized by aflatoxin production in vitro, morphology, and random amplified polymorphic DNAs. Aflatoxin B1 production differed significantly among vegetative compatibility groups; closely related isolates were similar intoxigenicity regardless of geographic origin. Cladistic analysis of DNA polymorphisms was consistent with vegetative compatibility data. A previously described dichotomy between S and L isolates of A. flavus based on morphology and physiology was strongly associated with both vegetative compatibility groups and DNA polymorphisms. All S isolates formed a single clade, apparently derived from the L group. Southern hybridizations of eight DNA amplification products showed that comigrating bands amplified by the same primer were always homologous within A. flavus but were not always homologous between A. flavus and closely related species. Results suggest that A. flavus is a species aggregate, that genotypes are dispersed over wide areas, and that aflatoxin production is more stable in nature than in culture. Key words: vegetative compatibility groups, random amplified polymorphic DNA, sclerotia, aflatoxin.

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