scholarly journals Ssu72 Regulates Fungal Development, Aflatoxin Biosynthesis and Pathogenicity in Aspergillus flavus

Toxins ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 717
Author(s):  
Guang Yang ◽  
Xiaohong Cao ◽  
Ling Qin ◽  
Lijuan Yan ◽  
Rongsheng Hong ◽  
...  
Keyword(s):  
Rna Polymerase Ii ◽  
Aspergillus Flavus ◽  
Pathogenic Fungus ◽  
Aflatoxin Production ◽  
Regulation Of Transcription ◽  
Aflatoxin Biosynthesis ◽  
Fungal Development ◽  
Oxidative Stresses ◽  
Novel Strategy ◽  
Phosphatase Ssu72

The RNA polymerase II (Pol II) transcription process is coordinated by the reversible phosphorylation of its largest subunit-carboxy terminal domain (CTD). Ssu72 is identified as a CTD phosphatase with specificity for phosphorylation of Ser5 and Ser7 and plays critical roles in regulation of transcription cycle in eukaryotes. However, the biofunction of Ssu72 is still unknown in Aspergillus flavus, which is a plant pathogenic fungus and produces one of the most toxic mycotoxins-aflatoxin. Here, we identified a putative phosphatase Ssu72 and investigated the function of Ssu72 in A. flavus. Deletion of ssu72 resulted in severe defects in vegetative growth, conidiation and sclerotia formation. Additionally, we found that phosphatase Ssu72 positively regulates aflatoxin production through regulating expression of aflatoxin biosynthesis cluster genes. Notably, seeds infection assays indicated that phosphatase Ssu72 is crucial for pathogenicity of A. flavus. Furthermore, the Δssu72 mutant exhibited more sensitivity to osmotic and oxidative stresses. Taken together, our study suggests that the putative phosphatase Ssu72 is involved in fungal development, aflatoxin production and pathogenicity in A. flavus, and may provide a novel strategy to prevent the contamination of this pathogenic fungus.

Inhibition of Aflatoxin Biosynthesis by Organophosphorus Compounds

1980 ◽  
Vol 43 (5) ◽  
pp. 381-384 ◽  
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.

scholarly journals NsdC and NsdD Affect Aspergillus flavus Morphogenesis and Aflatoxin Production

2012 ◽  
Vol 11 (9) ◽  
pp. 1104-1111 ◽  
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.

scholarly journals Proteogenomic characterization of the pathogenic fungus Aspergillus flavus reveals novel genes involved in aflatoxin production

2020 ◽  
pp. mcp.RA120.002144
Author(s):  
Mingkun Yang ◽  
Zhuo Zhu ◽  
Zhenhong Zhuang ◽  
Youhuang Bai ◽  
Shihua Wang ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Stress Responses ◽  
Splice Variants ◽  
Pathogenic Fungus ◽  
Aflatoxin Production ◽  
Mass Spectrometry Data ◽  
Single Amino Acid ◽  
High Quality ◽  
Novel Proteins ◽  
Wide Range

Aspergillus flavus (A. flavus), a pathogenic fungus, can produce carcinogenic and toxic aflatoxins that are a serious agricultural and medical threat worldwide. Attempts to decipher the aflatoxin biosynthetic pathway have been hampered by the lack of a high-quality genome annotation for A. flavus. To address this gap, we performed a comprehensive proteogenomic analysis using high-accuracy mass spectrometry data for this pathogen. The resulting high-quality dataset confirmed the translation of 8,724 previously-predicted genes, and identified 732 novel proteins, 269 splice variants, 447 single amino acid variants, 188 revised genes. A subset of novel proteins was experimentally validated by RT-PCR and synthetic peptides. Further functional annotation suggested that a number of the identified novel proteins may play roles in aflatoxin biosynthesis and stress responses in A. flavus. This comprehensive strategy also identified a wide range of post-translational modifications (PTMs), including 3,461 modification sites from 1,765 proteins. Functional analysis suggested the involvement of these modified proteins in the regulation of cellular metabolic and aflatoxin biosynthetic pathways. Together, we provided a high quality annotation of A. flavus genome and revealed novel insights into the mechanisms of aflatoxin production and pathogenicity in this pathogen.

scholarly journals Regulation of Morphology, Aflatoxin Production, and Virulence of Aspergillus flavus by the Major Nitrogen Regulatory Gene areA

Toxins ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 718 ◽  
Author(s):  
Opemipo Esther Fasoyin ◽  
Kunlong Yang ◽  
Mengguang Qiu ◽  
Bin Wang ◽  
Sen Wang ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Regulatory Gene ◽  
Nitrogen Sources ◽  
Aflatoxin Production ◽  
Fungal Species ◽  
Complete Medium ◽  
Over Expression ◽  
Oxidative Stresses ◽  
Gata Transcription Factor

Aspergillus flavus is a renowned plant, animal and human pathogen. areA is a global nitrogen regulatory gene of the GATA transcription factor family, shown to be the major nitrogen regulator. In this study, we identified areA in A. flavus and studied its function. The AreA protein contained a signatory zinc finger domain, which is extremely conserved across fungal species. Gene deletion (ΔareA) and over-expression (OE::areA) strains were constructed by homologous recombination to elucidate the role of areA in A. flavus. The ΔareA strain was unable to efficiently utilize secondary nitrogen sources for growth of A. flavus, and it had poorly developed conidiophores, when observed on complete medium, resulting in the production of significantly less conidia than the wild-type strain (WT). Aflatoxin B1 (AFB1) production was reduced in ΔareA compared with the WT strain in most conditions tested, and ΔareA had impaired virulence in peanut seeds. areA also played important roles in the sensitivity of A. flavus to osmotic, cell wall and oxidative stresses. Hence, areA was found to be important for the growth, aflatoxin production and pathogenicity of A. flavus. This work sheds light on the function of areA in the regulation of the nitrogen metabolism of A. flavus, and consequently aims at providing new ways for controlling the crossover pathogen, A. flavus.

Use of functional genomics to assess the climate change impact on Aspergillus flavus and aflatoxin production

2016 ◽  
Vol 9 (5) ◽  
pp. 665-672 ◽  
Author(s):  
M.K. Gilbert ◽  
B.M. Mack ◽  
G.A. Payne ◽  
D. Bhatnagar
Keyword(s):  
Climate Change ◽  
Functional Genomics ◽  
Aspergillus Flavus ◽  
Pathogenic Fungus ◽  
Regulatory Gene ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Transcriptomic Response ◽  
Climate Conditions ◽  
Change Impact

Aspergillus flavus is an opportunistic and pathogenic fungus that infects several crops of agricultural importance and under certain conditions may produce carcinogenic mycotoxins. Rising global temperatures, disrupted precipitation patterns and increased CO2 levels that are associated with future climate conditions are expected to impact the growth and toxigenic potential of A. flavus. Both laboratory and real world observations have demonstrated this potential, especially when examining the effects of water availability and temperature. Recent experiments have also established that CO2 may also be affecting toxin production. The application of current technologies in the field of functional genomics, including genomic sequencing, RNA-seq, microarray technologies and proteomics have revealed climate change-related, abiotic regulation of the aflatoxin cluster and influence on the plant-fungus interaction. Furthermore, elevated CO2 levels have been shown to impact expression of the aflatoxin biosynthetic regulatory gene aflR. The use of functional genomics will allow researchers to better understand the underlying transcriptomic response within the fungus to climate change, with a view towards predicting changes in fungal infection and toxin production associated with climate change.

Comparison of the Antifungal and Antiaflatoxigenic Potential of Liquid and Vapor Phase of Thymus vulgaris Essential Oil Against Aspergillus flavus

2019 ◽  
Vol 82 (12) ◽  
pp. 2044-2048
Author(s):  
FEI TIAN ◽  
SANG YOO LEE ◽  
HYANG SOOK CHUN
Keyword(s):  
Liquid Phase ◽  
Essential Oil ◽  
Aspergillus Flavus ◽  
Vapor Phase ◽  
Substantial Reduction ◽  
Brown Rice ◽  
Aflatoxin Production ◽  
Thymus Vulgaris ◽  
Aflatoxin Biosynthesis ◽  
Fungal Contamination

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

scholarly journals aflN Is Involved in the Biosynthesis of Aflatoxin and Conidiation in Aspergillus flavus

Toxins ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 831
Author(s):  
Kunzhi Jia ◽  
Lijuan Yan ◽  
Yipu Jia ◽  
Shuting Xu ◽  
Zhaoqi Yan ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Aspergillus Flavus ◽  
Prevention And Control ◽  
Reactive Oxygen Species Generation ◽  
Reactive Oxygen ◽  
Hyphal Growth ◽  
Aflatoxin Production ◽  
Oxygen Species ◽  
Aflatoxin Biosynthesis ◽  
And Control

Aspergillus flavus poses a threat to society economy and public health due to aflatoxin production. aflN is a gene located in the aflatoxin gene cluster, but the function of AflN is undefined in Aspergillus flavus. In this study, aflN is knocked out and overexpressed to study the function of AflN. The results indicated that the loss of AflN leads to the defect of aflatoxin biosynthesis. AflN is also found to play a role in conidiation but not hyphal growth and sclerotia development. Moreover, AlfN is related to the response to environmental oxidative stress and intracellular levels of reactive oxygen species. At last, AflN is involved in the pathogenicity of Aspergillus flavus to host. These results suggested that AflN played important roles in aflatoxin biosynthesis, conidiation and reactive oxygen species generation in Aspergillus flavus, which will be helpful for the understanding of aflN function, and will be beneficial to the prevention and control of Aspergillus flavus and aflatoxins contamination.

scholarly journals Transcriptomic Insights into Benzenamine Effects on the Development, Aflatoxin Biosynthesis, and Virulence of Aspergillus flavus

Toxins ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 70 ◽  
Author(s):  
Mingguan Yang ◽  
Laifeng Lu ◽  
Shuhua Li ◽  
Jing Zhang ◽  
Zhenjing Li ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Pathogenic Fungus ◽  
Underlying Mechanism ◽  
Aflatoxin Contamination ◽  
Mrna Levels ◽  
Aflatoxin Biosynthesis ◽  
Inhibitory Effects ◽  
Great Capacity ◽  
Aflatoxin Accumulation ◽  
New Strategies

Aspergillus flavus is a soilborne pathogenic fungus that poses a serious public health threat due to it contamination of food with carcinogenic aflatoxins. Our previous studies have demonstrated that benzenamine displayed strong inhibitory effects on the mycelial growth of A. flavus. In this study, we systematically investigated the inhibitory effects of benzenamine on the development, aflatoxin biosynthesis, and virulence in A. flavus, as well as the underlying mechanism. The results indicated that benzenamine exhibited great capacity to combat A. flavus at a concentration of 100 µL/L, leading to significantly decreased aflatoxin accumulation and colonization capacity in maize. The transcriptional profile revealed that 3589 genes show altered mRNA levels in the A. flavus after treatment with benzenamine, including 1890 down-regulated and 1699 up-regulated genes. Most of the differentially expressed genes participated in the biosynthesis and metabolism of amino acid, purine metabolism, and protein processing in endoplasmic reticulum. Additionally, the results brought us to a suggestion that benzenamine affects the development, aflatoxin biosynthesis, and pathogenicity of A. flavus via down-regulating related genes by depressing the expression of the global regulatory factor leaA. Overall, this study indicates that benzenamine have tremendous potential to act as a fumigant against pathogenic A. flavus. Furthermore, this work offers valuable information regarding the underlying antifungal mechanism of benzenamine against A. flavus at the level of transcription, and these potential targets may be conducive in developing new strategies for preventing aflatoxin contamination.

Warehouse Control of Aspergillus flavus Link and A. parasiticus Speare on Peanuts (Arachis hypogaea) by Phosphine Fumigation and its Effect on Aflatoxin Production

1996 ◽  
Vol 59 (4) ◽  
pp. 407-411 ◽  
Author(s):  
M. FERNANDA P. P. M. DE CASTRO ◽  
IVANIA A. PACHECO ◽  
LUCIA M. V. SOARES ◽  
REGINA P. Z. FURLANI ◽  
DALMO C. DE PAULA ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
High Moisture Content ◽  
High Moisture ◽  
Aluminum Phosphide ◽  
Fungal Development ◽  
Striking Increase ◽  
Ca 50 ◽  
Contamination Levels

Six stacks of 36 bags containing ca. 50 kg of unshelled peanuts with moisture contents in the range of 18.0 to 21.0% (wet basis) (average 19.3%) were formed in a commercial warehouse located in a peanut-producing area in São Paulo, Brazil. Three stacks were fumigated with phosphine for 7 days. An initial dose of 3.0 g of aluminum phosphide per m3 was applied. A second and a third application of the same dose were carried out 24 and 144 h later. Before fumigation, infection by Aspergillus flavus and/or A. parasiticus was either not detected in the peanut mass or was very low (1 to 13%), but contamination with aflatoxins (up to 191 μg/kg) was found in all stacks. After the fumigation treatments, a striking increase in infection was observed in the nonfumigated stacks (73 to 100% infected kernels) while in the fumigated stacks, A. flavus and/or A. parasiticus were either not detected or were isolated in insignificant amounts, indicating that phosphine was able to control fungal development in spite of the high moisture content of the kernels. After the fumigation period, the contamination levels of aflatoxins in the treated stacks remained unchanged, while the untreated stacks showed a staggering increase (up to 10,000 μg/kg of peanuts). After a month, however, no difference was observed in aflatoxin contamination and infection by A. flavus and A. parasiticus between the untreated and the treated stacks.

Sign in / Sign up

Export Citation Format

Share Document