Inhibitory effects of three monoterpenes from ginger essential oil on growth and aflatoxin production of Aspergillus flavus and their gene regulation in aflatoxin biosynthesis

ABSTRACT The antifungal and antiaflatoxigenic activity of Thymus vulgaris essential oil (EO) against Aspergillus flavus was evaluated over a range of concentrations in vapor- and liquid-phase contact tests. Total reduction in mycelial growth in the vapor- and liquid-phase tests was detected at EO concentrations of 20 and 400 μg/mL, respectively. Treatment with 10 μg/mL EO reduced aflatoxin production by 97.0 and 56.4% in the vapor- and liquid-phase tests, respectively. Greater inhibition of the expression of both fungal development–related genes (brlA, abaA, and wetA) and aflatoxin biosynthesis–related genes (aflR, aflD, and aflK) was also observed in the vapor-phase test. A substantial reduction in aflatoxin production was also observed in brown rice (72.7%) and white rice (18.0%). Our results indicate that the way this EO contacts fungal cells significantly affects its antifungal activity and that T. vulgaris EO in vapor phase might be a good strategy to control fungal contamination. HIGHLIGHTS

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Suppression of Aflatoxin Production by Essential Oil and Lactobacillus rhamnosus and Molecular Detection of Aflatoxin Biosynthesis aflR Gene Expression in Aspergillus flavus

Egyptian Journal of Microbiology ◽

10.21608/ejm.2015.235 ◽

2015 ◽

Vol 50 (1) ◽

pp. 61-82

Keyword(s):

Gene Expression ◽

Essential Oil ◽

Aspergillus Flavus ◽

Molecular Detection ◽

Lactobacillus Rhamnosus ◽

Aflatoxin Production ◽

Aflatoxin Biosynthesis

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The Inhibitory Effects ofCurcuma longaL. Essential Oil and Curcumin onAspergillus flavusLink Growth and Morphology

The Scientific World JOURNAL ◽

10.1155/2013/343804 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 20

Author(s):

Flávio Dias Ferreira ◽

Simone Aparecida Galerani Mossini ◽

Francine Maery Dias Ferreira ◽

Carla Cristina Arrotéia ◽

Christiane Luciana da Costa ◽

...

Keyword(s):

Essential Oil ◽

Aspergillus Flavus ◽

Culture Media ◽

Curcuma Longa ◽

Fungal Growth ◽

Aflatoxin Production ◽

Dependent Manner ◽

Inhibitory Effects ◽

Concentration Dependent Manner ◽

Spore Viability

The essential oil fromCurcuma longaL. was analysed by GC/MS. The major components of the oil were ar-turmerone (33.2%),α-turmerone (23.5%) andβ-turmerone (22.7%). The antifungal activities of the oil were studied with regard toAspergillus flavusgrowth inhibition and altered morphology, as preliminary studies indicated that the essential oil fromC. longainhibitedAspergillus flavusLink aflatoxin production. The concentration of essential oil in the culture media ranged from 0.01% to 5.0% v/v, and the concentration of curcumin was 0.01–0.5% v/v. The effects on sporulation, spore viability, and fungal morphology were determined. The essential oil exhibited stronger antifungal activity than curcumin onA. flavus. The essential oil reduced the fungal growth in a concentration-dependent manner.A. flavusgrowth rate was reduced byC. longaessential oil at 0.10%, and this inhibition effect was more efficient in concentrations above 0.50%. Germination and sporulation were 100% inhibited in 0.5% oil. Scanning electron microscopy (SEM) ofA. flavusexposed to oil showed damage to hyphae membranes and conidiophores. Because the fungus is a plant pathogen and aflatoxin producer,C. longaessential oil may be used in the management of host plants.

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Inhibition of Aflatoxin-Producing Fungi by Welsh Onion Extracts

Journal of Food Protection ◽

10.4315/0362-028x-62.4.414 ◽

1999 ◽

Vol 62 (4) ◽

pp. 414-417 ◽

Cited By ~ 21

Author(s):

J. J. FAN ◽

J. H. CHEN

Keyword(s):

Aspergillus Flavus ◽

Mycelial Growth ◽

Ethanol Extract ◽

Aflatoxin Production ◽

Inhibitory Effects ◽

Welsh Onion ◽

Extract Concentration ◽

Ph Values ◽

Ethanol Extracts ◽

Yeast Extract Sucrose

Welsh onion ethanol extracts were tested for their inhibitory activity against the growth and aflatoxin production of Aspergillus flavus and A. parasiticus. The survival of spores of A. flavus and A. parasiticus depended on both the extract concentration and the exposure time of the spores to the Welsh onion extracts. The mycelial growth of two tested fungi cultured on yeast extract–sucrose broth was completely inhibited in the presence of the Welsh onion ethanol extract at a concentration of 10 mg/ml during 30 days of incubation at 25°C. The extracts added to the cultures also inhibited aflatoxin production at a concentration of 10 mg/ml or permitted only a small amount of aflatoxin production with extract concentration of 5 mg/ml after 2 weeks of incubation. Welsh onion ethanol extracts showed more pronounced inhibitory effects against the two tested aflatoxin-producing fungi than did the same added levels of the preservatives sorbate and propionate at pH values near 6.5.

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Inhibition of Aflatoxin Biosynthesis by Organophosphorus Compounds

Journal of Food Protection ◽

10.4315/0362-028x-43.5.381 ◽

1980 ◽

Vol 43 (5) ◽

pp. 381-384 ◽

Cited By ~ 23

Author(s):

M. F. DUTTON ◽

M. S. ANDERSON

Keyword(s):

Aspergillus Flavus ◽

Organophosphorus Compound ◽

Organophosphorus Compounds ◽

Culture Fluid ◽

Aflatoxin Production ◽

The Other ◽

Aflatoxin Biosynthesis ◽

Inhibition Effect ◽

Type Activity ◽

Acetate Derivative

The effect of a range of organophosphorus and various other compounds on production of aflatoxin by Aspergillus flavus was investigated. Five organophosphorus compounds - Chlormephos, Ciodrin, Naled, Phosdrin and Trichlorphon- at concentrations of 20 and 100 μg/ml of culture fluid were found to have activity similar to Dichlorvos, in that they lowered the level of aflatoxin produced and caused formation of several anthraquinone pigments. Two of these pigments have not previously been described, one was named Versicol and a suggested structure is presented, whilst the other compound was shown to be its acetate derivative. A rationale is suggested for the required elements of structure, which are necessary for an organophosphorus compound to have Dichlorvos-type activity. Two unrelated compounds, ammonium nitrate and Tridecanone were also found to elicit Dichlorvos-type activity. It is likely that tridecanone or its breakdown products competitively inhibit enzymes involved in aflatoxin biosynthesis. It is possible that this inhibition effect explains the lowering of aflatoxin production in lipid-rich commodities infected by A. flavus.

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Evaluation of antifungal activity of Pittosporum undulatum L. essential oil against Aspergillus flavus and aflatoxin production

Ciência e Agrotecnologia ◽

10.1590/s1413-70542011000100008 ◽

2011 ◽

Vol 35 (1) ◽

pp. 71-76 ◽

Cited By ~ 9

Author(s):

Rosane Tamara da Silva Medeiros ◽

Edlayne Gonçalez ◽

Roberto Carlos Felicio ◽

Joana D'arc Felicio

Keyword(s):

Essential Oil ◽

Essential Oils ◽

Aspergillus Flavus ◽

Fungal Growth ◽

Aflatoxin Production ◽

Plant Oils ◽

Food Commodities ◽

And Storage ◽

Main Producer ◽

Mycelial Development

The presence of mycotoxins as a result of fungal attack can occur before, after and during the harvest and storage operations on agricultural crops and food commodities. Considering the inhibitory property of essential plant oils on the mycelial development of fungi and the importance of Aspergillus flavus, the main producer of aflatoxins, this research was designed to evaluate the toxicity of essential oil from Pittosporum undulatum against A. flavus. The essential oils were obtained from P. undulatum leaves, collected in different months and analyzed by GC/MS. The oils were rich in hydrocarbon, monoterpenes and sesquiterpenes and it was observed a significant variation on the chemical composition of the essential oil of leaves at different months. Besides, the essential oils were tested against fungal growth and the results showed different spectrum of inhibition on A. flavus. However, the essential oils inhibited the aflatoxin B1 production.

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Morphological and Transcriptomic Analysis of the Inhibitory Effects of Lactobacillus plantarum on Aspergillus flavus Growth and Aflatoxin Production

Toxins ◽

10.3390/toxins11110636 ◽

2019 ◽

Vol 11 (11) ◽

pp. 636 ◽

Cited By ~ 3

Author(s):

Zhao ◽

Zhang ◽

Folly ◽

Chang ◽

Wang ◽

...

Keyword(s):

Lactobacillus Plantarum ◽

Aspergillus Flavus ◽

Aflatoxin Production ◽

Inhibitory Effect ◽

Transcriptional Level ◽

Sequencing Data ◽

Inhibitory Effects ◽

Cell Wall Polysaccharides ◽

Colony Forming Units ◽

Insight Into

Lactobacillus plantarum, as a natural bio-preservative, has attracted a great deal of attention in recent years. In this study, 22 L. plantarum strains were tested against the aflatoxin-producing fungus, Aspergillus flavus; strain IAMU80070 showed the highest antifungal activity. At a concentration of 5 × 105 colony-forming units (CFU) mL−1, it completely inhibited A. flavus growth and decreased aflatoxin production by 93%. Furthermore, ultrastructural examination showed that IAMU80070 destroyed the cellular structure of hyphae and spores. To explore the inhibitory effect of IAMU80070 on A. flavus at the transcriptional level, transcriptome data were obtained and subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses. The aflatoxin biosynthetic process was the most significantly downregulated functional category, while genes implicated in the synthesis and organization of cell wall polysaccharides were upregulated. Quantitative real-time PCR results verified the credibility and reliability of the RNA sequencing data. These results provided insight into the transcriptome of A. flavus in response to the antagonistic effects of L. plantarum IAMU80070.

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NsdC and NsdD Affect Aspergillus flavus Morphogenesis and Aflatoxin Production

Eukaryotic Cell ◽

10.1128/ec.00069-12 ◽

2012 ◽

Vol 11 (9) ◽

pp. 1104-1111 ◽

Cited By ~ 66

Author(s):

Jeffrey W. Cary ◽

Pamela Y. Harris-Coward ◽

Kenneth C. Ehrlich ◽

Brian M. Mack ◽

Shubha P. Kale ◽

...

Keyword(s):

Aspergillus Flavus ◽

Strong Association ◽

Aflatoxin Production ◽

Expression Data ◽

Aflatoxin Biosynthesis ◽

Wild Type ◽

Content Type ◽

Conidium Formation ◽

In The Wild ◽

Type Gene

ABSTRACT The transcription factors NsdC and NsdD are required for sexual development in Aspergillus nidulans . We now show these proteins also play a role in asexual development in the agriculturally important aflatoxin (AF)-producing fungus Aspergillus flavus . We found that both NsdC and NsdD are required for production of asexual sclerotia, normal aflatoxin biosynthesis, and conidiophore development. Conidiophores in nsdC and nsdD deletion mutants had shortened stipes and altered conidial heads compared to those of wild-type A. flavus . Our results suggest that NsdC and NsdD regulate transcription of genes required for early processes in conidiophore development preceding conidium formation. As the cultures aged, the Δ nsdC and Δ nsdD mutants produced a dark pigment that was not observed in the wild type. Gene expression data showed that although AflR is expressed at normal levels, a number of aflatoxin biosynthesis genes are expressed at reduced levels in both nsd mutants. Expression of aflD , aflM , and aflP was greatly reduced in nsdC mutants, and neither aflatoxin nor the proteins for these genes could be detected. Our results support previous studies showing that there is a strong association between conidiophore and sclerotium development and aflatoxin production in A. flavus.

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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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