Taxonomy of Aspergillus section Flavi and their production of aflatoxins, ochratoxins and other mycotoxins

Insights into PUFA and oxylipin production from incubation of Aspergillus novoparasiticus in sugarcane juice

Understanding the metabolism of toxigenic fungi in food is crucial for public health. Fungi of the Aspergillus section Flavi are widespread in tropical and subtropical regions, infecting and producing mycotoxins in peanuts, nuts, cereals, and fruits. Classical Molecular Networking on the Global Natural Products Social Molecular Networking (GNPS) platform was applied to organize and guide the analysis of polyunsaturated fatty acids (PUFAs) and oxylipins, which are strongly associated with chemical communication between fungi and host plants during infection. Dereplication and molecular networking enabled visualization of the metabolome of A. novoparasiticus (ITAL-Y174 strain) incubated in sugarcane juice to mimic the fungal chemical response to plant lipids. The ITAL-Y174 strain produced PUFAs that differed from those of sugarcane. Oxylipins were detected early in the incubation (PGE1, 9,10-DiHOME, 13S-HODE). No known mycotoxins for A. novoparasiticus were detected, and kojic acid was identified, indicating a novel pathway to produce this important industrial natural product.

Impact of probiotic Lacticaseibacillus paracasei strain Shirota (LcS) on aflatoxin exposure among healthy Malaysian adults: a randomized, double-blind, placebo-controlled intervention study

BACKGROUND

Limited evidence suggests that probiotic Lacticaseibacillus paracasei strain Shirota (LcS) may reduce aflatoxin exposure in Malaysians, though individual factors influencing aflatoxin exposure remain unclear.

OBJECTIVES

This study evaluated the effect of LcS on aflatoxin biomarker levels over a 12-week intervention among healthy Malaysian adults. A secondary objective was to explore the individual factors associated with aflatoxin exposure using baseline data.

METHODS

A randomized, double-blind, placebo-controlled intervention involved healthy Malaysian adults (aged 20-60) of Chinese, Malay, or Indian ethnicities with elevated urinary aflatoxin M1 (AFM1) and serum aflatoxin B1 (AFB1)-albumin levels. Hundred and seventy-four (n=174) subjects were randomly and equally assigned (n=87/group) to consume either fermented milk with LcS (Probiotic) (3 x 1010 CFU/80 ml/bottle) or milk without LcS (Placebo) twice/day for 12 weeks, with a 4-week follow-up. Baseline data included socio-demographic characteristics, knowledge, attitude, and practice related to aflatoxin contamination, dietary intake, body weight and physical activity status. Urine and fasting blood samples were collected every two and four weeks for AFM1 and AFB1-lysine adduct analyses, respectively.

RESULTS

Eighty-five (n=85) and eighty-two (n=82) subjects in the Probiotic and Placebo groups completed the intervention, respectively. After adjusting for covariates, a significant effect was observed at post-intervention in the Probiotic group with a 23% reduction in urinary AFM1 levels compared to the Placebo group (B=-0.26; Exp(B)= 0.77; p=0.04). Serum AFB1-lysine adduct levels remained lower in the Probiotic group throughout the study. Both aflatoxin biomarkers significantly differed by ethnicity (AFM1: p=0.001; AFB1: p=0.01). Subjects with lower aflatoxin knowledge had significantly higher AFB1-lysine levels (mean rank=95.99) than those with higher knowledge (mean rank=73.57) (p=0.04). Urinary AFM1 levels were higher with cereal intake (ρ=0.17, p=0.03) but lower with protein intake (ρ=-0.18, p=0.02).

CONCLUSION

Ethnicity, knowledge level, and dietary intake influenced aflatoxin exposure. The benefits of consuming LcS to reduce aflatoxin exposure deserve further attention.

TRIAL REGISTRATION

This trial is registered in the National Medical Research Register (NMRR-16-2693-3230) and ClinicalTrials.gov (NCT03882294).

Effective novel and conventional technologies for decontamination of aflatoxin B1 in foods: a review

Aflatoxin B1 (AFB1) is a carcinogenic mycotoxin produced by certain filamentous fungi that contaminate agricultural crops. Conventional decontamination methods are still widely used to ensure food safety; however, novel technologies for AFB1 decontamination, while promising, aim to be efficient, cost-effective, and scalable. This article provides an overview of conventional and novel technologies used over the past decade to achieve AFB1 decontamination rates of 75% or higher, as well as patents related to aflatoxin decontamination. The results highlight various methods and their effectiveness in decontaminating AFB1 in rice, barley, maize, peanuts, millet, nuts, sorghum, wheat bran, pistachios, edible oils, dairy products, and certain culture media. Novel technologies include sorbents, cold atmospheric plasma, essential oils, phenolic compounds, and plant extracts, as well as magnetic materials and nanoparticles for AFB1 decontamination. Limitations associated with conventional methods have driven the search for novel approaches that, while showing great potential, often lack detailed explanations of their mechanisms of action and practical demonstrations on an industrial scale. Cold atmospheric plasma combined with high voltage is believed to hold significant promise for effectively reducing AFB1 in food while minimizing food residues. The new AFB1 decontamination methods described in this review can serve as valuable resources for researchers and industry stakeholders; however, further studies are needed to ensure global food safety.

A novel pan-fungal screening platform for antifungal drug discovery: proof of principle study

Broad-spectrum activity is a desirable property of novel antifungal drugs, but relevant in vitro testing is complicated by differential nutritional requirements and growth dynamics of fungal pathogens. Many screens for novel drugs are initiated against individual species or genera, with hit compounds later tested for "pan-fungal" activity. Hypothesizing that an optimized pan-fungal methodology would enhance the efficiency of early-stage drug discovery, a standardized assay was developed for a selection of World Health Organization-defined critical and high-priority fungal pathogens. Instead of using the standard susceptibility testing broth RPMI, an enriched media "fungal RPMI" (fRPMI), including multiple additional fungal growth-enhancing nutrients, was utilized. To assess utility for pan-fungal growth assessments, growth in fRPMI was compared to RPMI medium for 12 fungal pathogens. Growth was significantly improved in 7/12 species in fRPMI after 24 and/or 48 hours. For our proof-of-principle study, 500 chemical fragments from the Maybridge Ro3 Fragment library were screened at concentrations of 0.1 or 1 mM against five fungal pathogens: Aspergillus fumigatus, Candida albicans, Candida auris, Cryptococcus neoformans, and Nakaseomyces glabratus. Assay quality was assessed using z-factor analysis, and hits were normalized using a standard z-score to identify outliers. All assays achieved a high-quality z-factor (≥0.5) with readings at ≤24 hours, allowing the identification of 23 compounds with antifungal activity against at least one fungal species. From these, five compounds were identified as having pan-assay interference or broadly toxic properties. In conclusion, hits identified from pan-fungal phenotypic growth-based assays demonstrate reproducibility in all fungal species tested with carefully optimized conditions and precise timing.

Identification of miRNAs associated with Aspergillus flavus infection and their targets in groundnut (Arachis hypogaea L.)

BACKGROUND

The quality of groundnut produce is adversely impacted due to aflatoxin contamination by the fungus Aspergillus flavus. Although the transcriptomic control is not fully understood, the interaction between long non-coding RNAs and microRNAs in regulating A. flavus and aflatoxin contamination remains unclear. This study was carried out to identify microRNAs (miRNAs) to enhance the understanding of in vitro seed colonization (IVSC) resistance mechanism in groundnut.

RESULT

In this study, resistant (J 11) and susceptible (JL 24) varieties of groundnut were treated with toxigenic A. flavus (strain AF-11-4), and total RNA was extracted at 1 day after inoculation (1 DAI), 2 DAI, 3 DAI and 7 DAI. Seeds of JL 24 showed higher mycelial growth than J 11 at successive days after inoculation. A total of 208 known miRNAs belonging to 36 miRNA families, with length varying from 20-24 nucleotides, were identified, along with 27 novel miRNAs, with length varying from 20-22 nucleotides. Using psRNATarget server, 952 targets were identified for all the miRNAs. The targeted genes function as disease resistant proteins encoding, auxin responsive proteins, squamosa promoter binding like proteins, transcription factors, pentatricopeptide repeat-containing proteins and growth regulating factors. Through differential expression analysis, seven miRNAs (aly-miR156d-3p, csi-miR1515a, gma-miR396e, mtr-miR2118, novo-miR-n27, ptc-miR482d-3p and ppe-miR396a) were found common among 1 DAI, 2 DAI, 3 DAI and 7 DAI in J 11, whereas ten miRNAs (csi-miR159a-5p, csi-miR164a-3p, novo-miR-n17, novo-miR-n2, osa-miR162b, mtr-miR2118, ptc-miR482d-3p, ptc-miR167f-3p, stu-miR319-3p and zma-miR396b-3p) were found common among 1 DAI, 2 DAI, 3 DAI and 7 DAI in JL 24. Two miRNAs, ptc-miR482d-3p and mtr-miR2118, showed contrasting expression at different time intervals between J 11 and JL 24. These two miRNAs were found to target those genes with NBS-LRR function, making them potential candidates for marker development in groundnut breeding programs aimed at enhancing resistance against A. flavus infection.

CONCLUSION

This study enhances our understanding of the involvement of two miRNAs namely, ptc-miR482d-3p and mtr-miR2118, along with their NBS-LRR targets, in conferring resistance against A. flavus-induced aflatoxin contamination in groundnut under in vitro conditions.

Biodetoxification of both AFB1 and ZEN by Bacillus subtilis ZJ-2019-1 in gastrointestinal environment and in mice

Aflatoxin B1 (AFB1) and zearalenone (ZEN) are the most prevalent mycotoxins in production, posing a serious threat to human and animal health. Therefore, it is very urgent to find a safe and efficient method for the biodegradation of these mycotoxins. Our previous study demonstrated that Bacillus subtilis ZJ-2019-1 moderately degrades both mycotoxins in vitro and ZEN in female gilts. In this study, we assessed the effect of B. subtilis ZJ-2019-1 on AFB1 and ZEN degradation in naturally moldy corn gluten meal in a gastrointestinal environment while also evaluating the cytotoxicity of degradation products using the Cell Counting Kit-8 (CCK-8) assay. The efficacy of B. subtilis in degrading mycotoxins was further evaluated by orally administering 5 mg/kg AFB1 and 50 mg/kg ZEN to mice, followed by treatment with B. subtilis ZJ-2019-1 for 15 d. The results showed that B. subtilis ZJ-2019-1 moderately degraded both AFB1 and ZEN present in naturally moldy corn gluten meal in simulated small intestinal fluids, with degradation rates reaching 14.71% for AFB1 and 19.53% for ZEN respectively. Following degradation by B. subtilis ZJ-2019-1, the toxicity of resulting products from both AFB1 and ZEN decreased by 11.68-46.41% and 42.62-59.25%, respectively. Moreover, oral administration of B. subtilis ZJ-2019-1 exhibited remarkable detoxification effects on AFB1 and ZEN in mice, as evidenced by significant restoration of abnormal serum biochemical indices (including aspartate aminotransferase/alanine transaminase, alkaline phosphatase, total cholesterol, etc.) and alleviation of liver, intestine, and uterine damage caused by mycotoxins in mice. These findings indicate that B. subtilis ZJ-2019-1 possesses the ability to moderately degrade both AFB1 and ZEN, making it a promising candidate for biodegrading multi-mycotoxin contaminants in food and feed.

Occurrence and Diversity of Fungi and Their Mycotoxin Production in Common Edible and Medicinal Substances from China

Edible and medicinal substances can be contaminated by fungi during harvesting, processing, and storage, leading to mycotoxin production and quality deterioration. The distribution of mycotoxigenic fungi in edible and medicinal substances was investigated in this study. Fungi and mycotoxins were detected in 163 commercially available edible and medicinal substances using standard microbiological techniques and high-performance liquid chromatography. A total of 92.0% of samples contained fungi (0.5-5.3 lg colony-forming units (CFU)·g-1); 208 fungal strains belonging to 16 genera were identified, predominantly Aspergillus and Penicillium. Aspergillus section Nigri (30.3%) produced fumonisin B2, which was distributed mainly in radix and rhizome samples. Thirteen samples had mycotoxins, of which ochratoxin A was the most common, followed by aflatoxins and zearalenone (ZEN). One Nelumbinis semen sample contained 10.75 μg·kg-1 AFB1, and one Raisin tree semen sample contained 484.30 μg·kg-1 ZEN, which exceeded regulatory limits in Europe and China. These findings highlight the potential risks associated with fungal contamination and mycotoxins in edible and medicinal substances. Enhanced quality control measures are essential to reduce contamination during harvesting, processing, and storage. Expanded mycotoxin screening, improved preservation techniques, and stricter regulatory standards need to be implemented to ensure consumer safety.

Fungi: Pioneers of chemical creativity - Techniques and strategies to uncover fungal chemistry

Natural product discovery from fungi for drug development and description of novel chemistry has been a tremendous success. This success is expected to accelerate even further, owing to the advent of sophisticated technical advances of technical advances that recently led to the discovery of an unparalleled biodiversity in the fungal kingdom. This review aims to give an overview on i) important secondary metabolite-derived drugs or drug leads, ii) discuss the analytical and strategic framework of how natural product discovery and drug lead identification transformed from earlier days to the present, iii) how knowledge of fungal biology and biodiversity facilitates the discovery of new compounds, and iv) point out endeavors in understanding fungal secondary metabolite chemistry in order to systematically explore fungal genomes by utilizing synthetic biology. An outlook is given, underlining the necessity for a collaborative and cooperative scenario to harness the full potential of the fungal secondary metabolome.

Structural Similarity, Activity, and Toxicity of Mycotoxins: Combining Insights from Unsupervised and Supervised Machine Learning Algorithms

A large number of mycotoxins and related fungal metabolites have not been assessed in terms of their toxicological impacts. Current methodologies often prioritize specific target families, neglecting the complexity and presence of co-occurring compounds. This work addresses a fundamental question: Can we assess molecular similarity and predict the toxicity of mycotoxins in silico using a defined set of molecular descriptors? We propose a rapid nontarget screening approach for multiple classes of mycotoxins, integrating both unsupervised and supervised machine learning models, alongside molecular and physicochemical descriptors to enhance the understanding of structural similarity, activity, and toxicity. Clustering analyses identify natural clusters corresponding to the known mycotoxin families, indicating that mycotoxins belonging to the same cluster share similar molecular properties. However, topological descriptors play a significant role in distinguishing between acutely toxic and nonacutely toxic compounds. Random forest (RF) and neural networks (NN), combined with molecular descriptors, contribute to improved knowledge and predictive capability regarding mycotoxin toxicity profiles. RF allows the prediction of toxicity using data reflecting mainly structural features and performs well in the presence of descriptors reflecting biological activity. NN models prove to be more sensitive to biological activity descriptors than RF. The use of descriptors encompassing structural complexity and diversity, chirality and symmetry, connectivity, atomic charge, and polarizability, together with descriptors representing lipophilicity, absorption, and permeation of molecules, is crucial for predicting toxicity, facilitating broader toxicological evaluations.

Phylogenetic studies and distinction of aflatoxin-producing Aspergillus species in section Flavi, Ochraceorosei and Nidulantes: A review

Aspergillus species produce polyketides, which form the basis of aflatoxins, some of the most significant mycotoxins in agriculture. Aflatoxins contaminate cereals, oilseeds, and nuts, both in the field and during storage. Of the 13 naturally occurring aflatoxins, the most potent are aflatoxins B1, B2, G1, and G2. The primary aflatoxigenic species are A. flavus, A. parasiticus, and A. nomius, while A. arachidicola, A. minisclerotigenes, and A. saccharicola also documented. These aflatoxin producers belong to three sections- 'Flavi', 'Ochraceorosei', and 'Nidulantes.' Aspergillus flavus, within section Flavi, shows morphological diversity, classified into Group I (S- and L- strains) and Group II (S- strains), with S-strains producing higher levels of aflatoxins. Aflatoxin biosynthesis is primarily regulated by the aflR gene, though other genes like aflS, aflP, aflQ, aflC, and aflM are also associated. However, presence of the aflR gene does not guarantee aflatoxin production across species. Sterigmatocystin serves as a precursor molecule within the pathway leading to aflatoxin production. Phylogenetic assessment, using ITS, BenA, CaM, and RBP2 gene sequences, reveals distinct clusters within Aspergillus sections and highlights the co-evolution of aflatoxigenic and non-aflatoxigenic species. Aspergillus ochraceoroseus and A. rambellii diverged out of aflatoxin-producing species earlier in evolutionary history, before splitting from a shared ancestor with A. fumigatus, which neither produces aflatoxins nor sterigmatocystin. Non-aflatoxigenic species like A. oryzae may evolve from aflatoxigenic species like A. flavus due to variations in evolutionary rates, telomere deletions, and mutations in aflatoxin biosynthesis genes. Comparative genomic analysis of AF, AF/ST and ST gene cluster shows that A. flavus has a larger aflatoxin gene cluster, while A. ochraceoroseus lacks the genes aflP and aflQ. Additionally, A. ochraceoroseus and A. rambellii possess a smaller genome, suggesting that genetic drift and deletions have refined their genomes for more efficient aflatoxin production.

Stonebrood Disease-Histomorphological Changes in Honey Bee Larvae (Apis mellifera) Experimentally Infected with Aspergillus flavus

Stonebrood (Aspergillus sp.) is a rare, poorly described disease of the Western honey bee (Apis mellifera) that can affect adult bees and brood. This study describes the pathogenesis using artificially reared pathogen-free Apis mellifera larvae, experimentally infected (5 × 102 spores/larva) with Aspergillus flavus. Between days 1 and 5 p.i. (larval age 4 until 8 days), five uninfected control larvae, up to five infected living larvae, and up to five infected dead larvae were examined macroscopically. Subsequently, the larvae were photographed, fixed (4% formaldehyde), and processed for histological examination (hematoxylin-eosin stain, Grocott silvering). Sections were digitized, measured (area, thickness), and statistically analyzed. In total, 19 of the 43 collected infected larvae showed signs of infection (germinating spores/fungal mycelium): dead larvae (from day 2 p.i.) showed clear histological and macroscopic signs of infection, while larvae collected alive (from day 1 p.i.) were only locally affected. Infected larvae were significantly smaller (day 2 p.i.: p < 0.001, 4 p.i.: p < 0.01, 5 p.i.: p < 0.01) than uninfected larvae (control group). Our study shows that the pathogenesis of stonebrood is characterized by a short period between Aspergillus germination and the onset of disease (about one day), and a rapid larval death.

Assessment of mycotoxins in infant flour and their decontamination in raw material during production processes in Ouagadougou

The infant flours produced in Burkina Faso are essentially a mixture of cereals and legumes. These raw materials are frequently contaminated with mycotoxins which pose a huge food safety and public health threat. The objective of this study was to determine mycotoxin levels in raw materials and infant flours in Ouagadougou and to investigate the impact of decontamination on the raw materials used in infant flour production. A total of 22 cereals and 17 legumes as raw materials and 26 infant flour samples were analysed for aflatoxins, fumonisin B1 (FB1), and ochratoxin A (OTA) by liquid chromatography coupled to tandem mass spectrometry, while saline treatment and hand-sorting of grains in mycotoxin reduction were tested. All the samples of raw materials and infant flours were contaminated with aflatoxins, whereas 20.5% and 38.5% of raw materials and 57.7% and 61.5% of infant flours, respectively, were contaminated by FB1 and OTA. These decontamination assays significantly reduced the levels of mycotoxins. AFB1 was reduced by 48% after soaking of maize for 6 h in a 6% NaCl solution. Sorting resulted in a 92% reduction in AFB1 content in peanut. However, soaking in saline solution did not reduce the FB1 and OTA contents. Sorting did not also reduce FB1 contents in peanut. Sorting and soaking in 6% saline solution for 6 h are production processes that lead to a reduction in the level of contamination by aflatoxins in maize and peanut used as raw materials for infant flour production.

A silent killer in the word: Review on Aspergillus flavus strains

Filamentous fungi are recognized for their significance in food processing and antibiotic production, as well as their capacity to produce mycotoxins. Numerous secondary metabolites have been investigated, and their occurrence in foodstuffs, both in the field and during the storage of agricultural products, poses a substantial health risk to consumers. Several fungal species capable of producing mycotoxins have been documented. However, their presence suggests the potential occurrence of mycotoxins, of which only the most well-known are considered in health risk assessment, thus potentially underestimating the complex mixture to which consumers may be exposed. This review examines the range of secondary metabolites produced by Aspergillus species of the Flavi section found in agricultural products and foodstuffs. Known for their ability to produce aflatoxins, the presence of these fungi typically leads to the investigation of only aflatoxins, and possibly cyclopiazonic acid, in contaminated foods. This review elucidates the secondary metabolites produced by the Flavi section of Aspergillus and examines the associated hazards, to contribute to the assessment of the potential risk that the presence of these fungi in food products may represent.

Microbial Contamination and Food Safety Aspects of Cassava Roasted Flour ("Rale") in Mozambique

Cassava is an important staple food that contributes to the food security of small-scale Mozambican farmers. In southern Mozambique, cassava roots are usually processed into cassava roasted flour, locally known as "rale". The handling and processing practices connected to "rale" production may introduce microbial contamination. We assessed the microbial contamination of "rale" processed in local farmers' associations and consumed either locally or sold in rural markets. Microbial sampling was carried out both during the warmer rainy and cooler dry seasons, and microorganisms of relevance for food safety and fermentation were enumerated. The results revealed variation in terms of microbial diversity in all stages of cassava root processing. In samples collected in the warmer rainy season, molds, lactic acid bacteria, general aerobic bacteria and Bacillus spp. were isolated, whereas in samples collected in the cooler dry season, other groups of microorganisms such as yeasts and Staphylococcus aureus were present. Wickerhamomyces anomalus, Rhodotorula mucilaginosa, Pichia exigua, Meyerozyma caribbica and Torulaspora delbrueckii were the most frequent yeast species found within the cassava processing stages. Aflatoxin-producing molds were observed infrequently in this study, and only at low counts, thus, the risk for aflatoxin contamination appears to be low. The results obtained from the Illumina 16S rRNA gene sequencing can be considered a complementary technique to the plating methods relied on in this study. From a food quality and safety point of view, this staple food does not appear to pose a high risk for foodborne disease.

Efficient Expression and Activity Optimization of Manganese Peroxidase for the Simultaneous Degradation of Aflatoxins AFB1, AFB2, AFG1, and AFG2

Aflatoxins (AFs), notorious mycotoxins that pose significant risks to human and animal health, make biodegradation extremely crucial as they offer a promising approach to managing and reducing their harmful impacts. In this study, we identified a manganese peroxidase from Punctularia strigosozonata (PsMnp) through protein similarity analysis, which has the capability to degrade four AFs (AFB1, AFB2, AFG1, and AFG2) simultaneously. The gene encoding this enzyme was subject to codon optimization, followed by cold shock induction expression using the pColdII vector, leading to the soluble expression of manganese peroxidase (Mnp) in Escherichia coli. This study tackled the problem of inclusion body formation that often occurs during Mnp expression in E. coli. After optimizing the degradation conditions, the degradation rates for AFB1, AFB2, AFG1, and AFG2 were 87.9, 72.8, 77.3, and 85.6%, respectively. Molecular docking and molecular dynamics simulations indicated that PsMnp facilitated the degradation of AFs through hydrophobic and polar interactions among various amino acid residues. This research offers novel insights into the rapid discovery of enzymes capable of degrading AFs and establishes a theoretical foundation for the efficient expression of mycotoxin detoxification enzymes.

Study of endophytic fungi of Ipomoea pes-caprae reveals the superiority of in situ plant conservation over ex situ conservation from a mycological view

In nature conservation, ex situ and in situ conservation strategies are discussed for protecting endangered species of plants and animals. However, the impacts of these strategies on the microbes associated with these species are rarely considered. In our study, we chose the endophytic fungi of the pantropical creeping plant Ipomoea pes-caprae as representative coastal plant in two natural coastal populations and two botanical gardens in Taiwan as collection sites in order to investigate the potential effect of ex situ plantation on the biodiversity of microbes intimately associated with this plant. In a culture-dependent approach, endophytic fungi were isolated under axenic conditions and identified to species, genus, or higher taxonomic ranks with DNA barcodes and morphology. In addition to yielding ca. 800 strains and over 100 morphospecies, a principal component analysis (PCA) of the distribution of the dominant fungal species showed clear differences in the composition of endophytic fungal species depending on the sampling sites. We conclude that the endophytic fungi from the original site are replaced by other species in the ex situ plantations. Due to the limitations of ex situ conservation of microbes and from a mycological and microbial perspective, in situ conservation should outweigh ex situ approaches.

The Effect of Temperature over the Growth and Biofilm Formation of the Thermotolerant Aspergillus flavus

Aspergillus flavus is a medically relevant fungus, particularly in tropical regions. Although its aflatoxin production and thermotolerance are well documented, its biofilm-forming ability has received less attention, despite being a key factor in the virulence of A. flavus as an opportunistic pathogen, which can significantly impact therapeutic outcomes. To investigate the influence of temperature on the growth and biofilm formation of an A. flavus isolate, we compared it on solid media with the reference strain A. flavus ATCC 22546 and documented morphological changes during conidial germination. We examined biofilm formation in both strains across different temperatures and evaluated the susceptibility of this A. flavus isolate to antifungal agents in both planktonic and biofilm form. Our results showed that the temperature can promote conidiation on solid media. Radial growth was highest at 28 °C, while the conidial count and density were favored at higher temperatures. Moreover, we determined that 37 °C was the optimal temperature for conidial germination and biofilm formation. We described four distinct phases in A. flavus biofilm development-initiation (0-12 h), consolidation (12-24 h), maturation (24-48 h), and dispersion (48-72 h)-with the notable presence of conidial heads at 42 °C. Carbohydrates and proteins constitute the primary components of the extracellular matrix. We observed an abundance of lipid droplets within the hyphae of the MMe18 strain biofilm. The mature biofilms demonstrated reduced susceptibility to amphotericin B and itraconazole, requiring higher inhibitory concentrations for both antifungals compared with their planktonic counterparts.

Species Diversity and Distribution of Non-fumigatus Aspergillus Species in Ogasawara Islands, Japan

Aspergillus sections Flavi, Nigri, and Terrei are known as common causative agents of aspergillosis, followed by section Fumigati. A previous study investigated the distribution of section Fumigati in Izu and Ogasawara Islands and found that the dominant species changes depending on the soil environment. This study investigated the species diversity and distribution of sections Flavi, Nigri, and Terrei in Mukojima, Hahajima, and Chichijima of Ogasawara Islands and clarified whether the dominant species vary depending on the soil environment, as in section Fumigati. The strains were isolated from soil samples collected in 2019 and 2020 at 18 sites in three islands, including different landscapes, and species identification was based on the nucleotide sequence of the calmodulin gene. Overall, 172 strains were isolated from all sites and identified to seven section Flavi, five section Nigri, and three section Terrei species. Three section Flavi, three section Nigri, and one section Terrei species have been reported as causative agents of aspergillosis. Three sections were distributed in Chichijima and Hahajima, but only section Nigri was found in Mukojima. The frequency of occurrence of Aspergillus tamarii and Aspergillus nomiae belonging to section Flavi and Aspergillus niger and Aspergillus tubingensis belonging to section Nigri were > 60% in forests, including shrub forests, whereas that of Aspergillus floccosus belonging to section Terrei was > 40% in bare land and grassland. Aspergillus pseudonomiae belonging to section Flavi was isolated at > 40% frequency of occurrence regardless of the landscape. Thus, differences of soil environments affected the distribution of the dominant species belonging to three sections.

A Review of the Mycotoxin Family of Fumonisins, Their Biosynthesis, Metabolism, Methods of Detection and Effects on Humans and Animals

Fumonisins, a class of mycotoxins predominantly produced by Fusarium species, represent a major threat to food safety and public health due to their widespread occurrence in staple crops including peanuts, wine, rice, sorghum, and mainly in maize and maize-based food and feed products. Although fumonisins occur in different groups, the fumonisin B series, particularly fumonisin B1 (FB1) and fumonisin B2 (FB2), are the most prevalent and toxic in this group of mycotoxins and are of public health significance due to the many debilitating human and animal diseases and mycotoxicosis they cause and their classification as by the International Agency for Research on Cancer (IARC) as a class 2B carcinogen (probable human carcinogen). This has made them one of the most regulated mycotoxins, with stringent regulatory limits on their levels in food and feeds destined for human and animal consumption, especially maize and maize-based products. Numerous countries have regulations on levels of fumonisins in foods and feeds that are intended to protect human and animal health. However, there are still gaps in knowledge, especially with regards to the molecular mechanisms underlying fumonisin-induced toxicity and their full impact on human health. Detection of fumonisins has been advanced through various methods, with immunological approaches such as Enzyme-Linked Immuno-Sorbent Assay (ELISA) and lateral flow immunoassays being widely used for their simplicity and adaptability. However, these methods face challenges such as cross-reactivity and matrix interference, necessitating the need for continued development of more sensitive and specific detection techniques. Chromatographic methods, including HPLC-FLD, are also employed in fumonisin analysis but require meticulous sample preparation and derivitization due to the low UV absorbance of fumonisins. This review provides a comprehensive overview of the fumonisin family, focusing on their biosynthesis, occurrence, toxicological effects, and levels of contamination found in foods and the factors affecting their presence. It also critically evaluates the current methods for fumonisin detection and quantification, including chromatographic techniques and immunological approaches such as ELISA and lateral flow immunoassays, highlighting the challenges associated with fumonisin detection in complex food matrices and emphasizing the need for more sensitive, rapid, and cost-effective detection methods.

New insights into the combined effects of aflatoxin B1 and Eimeria ovinoidalis on uterine function by disrupting the gut-blood-reproductive axis in sheep

BACKGROUND

Sheep coccidiosis is an infectious parasitic disease that primarily causes diarrhea and growth retardation in young animals, significantly hindering the development of the sheep breeding industry. Cereal grains and animal feeds are frequently contaminated with mycotoxins worldwide, with aflatoxin B1 (AFB1) being the most common form. AFB1 poses a serious threat to gastrointestinal health upon ingestion and affects the function of parenteral organs, thus endangering livestock health. However, the impact of the combined effects of coccidia and AFB1 on the reproductive system of sheep has not been reported. Therefore, this study utilized sheep as an animal model to investigate the mechanisms underlying the reproductive toxicity induced by the individual or combined effects of AFB1 and Eimeria ovinoidalis (E. ovinoidalis) on the gut-blood-reproductive axis.

RESULTS

The results showed that AFB1 and coccidia adversely affect the reproductive system defense of sheep by altering uterine histopathology and hormone levels and triggering inflammation, which is associated with changes in the gut microbiota and metabolites. Moreover, co-exposure to AFB1 and coccidia disrupted the intestinal structure of the colon, resulting in reduced crypt depth. The impaired barrier function of the colon manifests primarily through the suppression of barrier protein expression, changes in the gut microbiome composition, and disruptions in gut metabolism. Importantly, the levels of blood inflammatory factors (IL-6, IL-10, TNF-α, and LPS) increased, suggesting that exposure to AFB1 and coccidia compromises the function of uterine organs in sheep by perturbing the gut-blood-reproductive axis. Blood metabolomics analysis further revealed that the differential metabolites predominantly concentrate in the amino acid pathway, particularly N-acetyl-L-phenylalanine. This metabolite is significantly correlated with IL-6, TNF-α, LPS, ERα, and ERβ, and it influences hormone levels while inducing uterine damage through the regulation of the downstream genes PI3K, AKT, and eNOS in the relaxin signaling pathway, as demonstrated by RNA sequencing.

CONCLUSIONS

These findings reveal for the first time that the combined effects of AFB1 and E. ovinoidalis on sheep uterine function operate at the level of the gut-blood-reproductive axis. This suggests that regulating gut microbiota and its metabolites may represent a potential therapeutic strategy for addressing mycotoxins and coccidia-co-induced female reproductive toxicity.

Metabolic modelling uncovers the complex interplay between fungal probiotics, poultry microbiomes, and diet

BACKGROUND

The search for alternatives to antibiotic growth promoters in poultry production has increased interest in probiotics. However, the complexity of the interactions between probiotics, gut microbiome, and the host hinders the development of effective probiotic interventions. This study explores metabolic modelling to examine the possibility of designing informed probiotic interventions within poultry production.

RESULTS

Genomic metabolic models of fungi were generated and simulated in the context of poultry gut microbial communities. The modelling approach correlated with short-chain fatty acid production, particularly in the caecum. Introducing fungi to poultry microbiomes resulted in strain-specific and diet-dependent effects on the gut microbiome. The impact of fungal probiotics on microbiome diversity and pathogen inhibition varied depending on the specific strain, resident microbiome composition, and host diet. This context-dependency highlights the need for tailored probiotic interventions that consider the unique characteristics of each poultry production environment.

CONCLUSIONS

This study demonstrates the potential of metabolic modelling to elucidate the complex interactions between probiotics, the gut microbiome, and diet in poultry. While the effects of specific fungal strains were found to be context-dependent, the approach itself provides a valuable tool for designing targeted probiotic interventions. By considering the specific characteristics of the host microbiome and dietary factors, this methodology could guide the deployment of effective probiotics in poultry production. However, the current work relies on computational predictions, and further in vivo validation studies are needed to confirm the efficacy of the identified probiotic candidates. Nonetheless, this study represents a significant step in using metabolic models to inform probiotic interventions in the poultry industry. Video Abstract.

Recent progress, challenges, and future perspectives of electrochemical biosensing of aflatoxins

Aflatoxins (AFs), produced by fungi, are highly hazardous and classified as mycotoxins. Controlling their levels is of significant concern. This group consists of 20 fungal metabolites, all structurally derived from difuranocoumarin. Exposure to AFs through food can cause critical health issues, such as cancers, deformities, and mutations, posing a significant global public health issue. The inherent dangers of AF exposure necessitate swift and reliable detection techniques to identify its presence in food products. The rise of nanotechnology has opened doors to innovative electrochemical biosensors, offering a promising solution to this pressing issue. This review delves into nanomaterial-based aptasensors, immunosensors, and molecularly imprinted polymers, the predominant electrochemical biosensors developed for AF detection. This paper offers a broad summary of recent advancements in biosensor technology in electrochemical sensing of AFs, alongside challenges to overcome limitations, and future perspectives.

Aspergillus ullungdoensis sp. nov., Penicillium jeongsukae sp. nov., and other fungi from Korea

Eurotiales fungi are thought to be distributed worldwide but there is a paucity of information about their occurrence on diverse substrates or hosts and at specific localities. Some of the Eurotiales, including Aspergillus and Penicillium species, produce an array of secondary metabolites of use for agricultural, medicinal, and pharmaceutical applications. Here, we carried out a survey of the Eurotiales in South Korea, focusing on soil, freshwater, and plants (dried persimmon fruits and seeds of Perilla frutescens, known commonly as shiso). We obtained 11 species that-based on morphology, physiology, and multi-locus (ITS, BenA, CaM, and RPB2) phylogenetic analyses-include two new species, Aspergillus ullungdoensis sp. nov. and Penicillium jeongsukae sp. nov., and nine species that were known, but previously not described in South Korea, Aspergillus aculeatinus, Aspergillus aurantiacoflavus, Aspergillus croceiaffinis, Aspergillus pseudoviridinutans, Aspergillus uvarum, Penicillium ferraniaense, Penicillium glaucoroseum, Penicillium sajarovii, and one, Penicillium charlesii, that was isolated from previously unknown host, woodlouse (Porcellio scaber). We believe that biodiversity survey and identifying new species can contribute to set a baseline for future changes in the context of humanitarian crises such as climate change.

Monitoring fungi and mycotoxin potential in pistachio nuts of Turkish origin: A snap-shot for climate change scenario

Pistachio (Pistacia vera L.) is an economically important tree nut. Due to its nutritional properties and health benefits, it is considered a healthy food and thus widely consumed worldwide. However, fungal contamination of the commodities has received considerable attention because of possible contamination by toxigenic fungi, important source of mycotoxins, resulting from secondary metabolism and hazards to health consumer. Members of the genus Aspergillus, mainly Aspergillus flavus and Aspergillus niger, are reported as occurring most frequently on pistachio nuts, because able to grow in the presence of low amounts of water and to produce mycotoxins (aflatoxins and ochratoxins), that are well known for their harmful health effects on humans. Monitoring the contaminating fungal species is particularly worthy of note also in climate change scenario, allowing to notice changes in fungal population composition through the time. This study aimed to contribute to collect data about fungal population and mycotoxins occurred in pistachio samples collected in Turkey: prevalence of 2 species, A. flavus and Aspergillus tubingensis, was assessed. The A. flavus strains consisted of a mixed population of aflatoxin producers and non-producing strains in vitro, with evidence of a new genotype in gene cluster within strains of aflatoxin non-producing chemotype.

Maize-Fusarium associations and their mycotoxins: Insights from South Africa

For maize, a staple food in South Africa, there is a lack of comprehensive knowledge on the mycotoxin-producing fungal diversity. In this study, a fungal community profile was established using culture-dependent methods for 56 maize seed samples that were also analysed for 13 mycotoxins. The fungal isolates were identified by morphology and DNA sequencing. A total of 723 fungal isolates from 21 genera and 99 species were obtained and characterised. Fusarium was the most common genus (isolated from 52 samples), followed by Cladosporium (n = 45), Aspergillus (n = 41), Talaromyces (n = 40), and Penicillium (n = 38). Fusarium communities were dominated by the Fusarium fujikuroi species complex, which includes species such as Fusarium verticillioides and Fusarium temperatum, while Fusarium awaxy and Fusarium mirum are reported here for the first time from South Africa. As for the deoxynivalenol (DON) producing species, only Fusarium boothii and Fusarium graminearum were isolated to a lesser extent. DON (n = 37), fumonisins (FUM) (n = 32), and zearalenone (ZEA) (n = 6) were detected. The presence of a particular species did not guarantee the presence of the corresponding mycotoxins, while the inverse was also true. The occurrence of DON and/or FUM in South African maize remains a health concern, so continuous monitoring of both fungal species and their mycotoxins is important.

Assessing Olive Oil Quality Using Different DNA-Based Methods

Olive oil is appreciated worldwide for its unique nutritional and organoleptic properties. It is rich in unsaturated fatty acids and antioxidants, which are well-known for their health benefits. The qualitative characteristics of olive oil can be adversely affected by various biotic and abiotic factors. Particularly, microbial pathogens, such as mold fungi, can cause the deterioration of the oil and, thus, be a serious risk to consumer health. In this study, the effectiveness of DNA-based methods, i.e., endpoint PCR, Real-Time PCR (RT-PCR), and loop-mediated isothermal amplification (LAMP), all based on the ITS2-28S region, were used to evaluate the fungal contamination of samples of extra virgin olive oil. All the DNA techniques were able to detect, albeit at different levels, fungal infections affecting some of the basic quality parameters of the olive oils analyzed. However, compared to endpoint PCR and/or RT-PCR, the LAMP assay greatly simplified and accelerated the identification of pathogenic mold in the oil samples. This may encourage the olive oil industry to adopt this method in order to offer the consumer an oil with specific health parameters and therefore guarantee the safety and quality of this precious food product.

Mitigation of aflatoxin contamination of maize, groundnut, and sorghum by commercial biocontrol products in farmers' fields across Burkina Faso, Mali, Niger, and Togo

Background

Aflatoxin contamination by Aspergillus section Flavi fungi poses a significant threat to food security and public health in sub-Saharan Africa (SSA). Maize, groundnut, and sorghum are staple crops frequently contaminated with aflatoxins, sometimes at dangerous levels. Despite its detrimental effects, many farmers in SSA lack access to effective tools for mitigating aflatoxin contamination. Biocontrol based on atoxigenic isolates of A. flavus is an effective tool to limit aflatoxin contamination.

Methods

The development, testing, registration, and commercial use of the aflatoxin biocontrol product Aflasafe BF01 for use in Burkina Faso is described. In addition, the deployment of the biocontrol technology across Mali, Niger, and Togo is documented, and for the first time, the use of aflatoxin biocontrol in sorghum is reported.

Results

In all four countries, treated crops had significantly (P < 0.05) less aflatoxins than crops from untreated fields. Most treated crops met the stringent tolerance threshold for human consumption, 4 ppb total aflatoxin. Using native atoxigenic isolates of A. flavus and employing a multi-disciplinary approach, aflatoxin biocontrol products have demonstrated significant success in reducing aflatoxin levels in treated crops compared to untreated ones.

Conclusions

This multi-year, multi-funded source study underscores the effectiveness of biocontrol strategies in mitigating aflatoxin contamination at scale, offering a regional approach for sustainable management in West Africa and potentially unlocking significant health and economic benefits for the region.

Supplementary Information

The online version contains supplementary material available at 10.1186/s43170-024-00313-3.

Pre- and post-harvest aflatoxin contamination and management strategies of Aspergillus spoilage in East African Community maize: review of etiology and climatic susceptibility

Globally, maize (Zea mays L.) is deemed an important cereal that serves as a staple food and feed for humans and animals, respectively. Across the East African Community, maize is the staple food responsible for providing over one-third of calories in diets. Ideally, stored maize functions as man-made grain ecosystems, with nutritive quality changes influenced predominantly by chemical, biological, and physical factors. Food spoilage and fungal contamination are convergent reasons that contribute to the exacerbation of mycotoxins prevalence, particularly when storage conditions have deteriorated. In Kenya, aflatoxins are known to be endemic with the 2004 acute aflatoxicosis outbreak being described as one of the most ravaging epidemics in the history of human mycotoxin poisoning. In Tanzania, the worst aflatoxin outbreak occurred in 2016 with case fatalities reaching 50%. Similar cases of aflatoxicoses have also been reported in Uganda, scenarios that depict the severity of mycotoxin contamination across this region. Rwanda, Burundi, and South Sudan seemingly have minimal occurrences and fatalities of aflatoxicoses and aflatoxin contamination. Low diet diversity tends to aggravate human exposure to aflatoxins since maize, as a dietetic staple, is highly aflatoxin-prone. In light of this, it becomes imperative to formulate and develop workable control frameworks that can be embraced in minimizing aflatoxin contamination throughout the food chain. This review evaluates the scope and magnitude of aflatoxin contamination in post-harvest maize and climate susceptibility within an East African Community context. The paper also treats the potential green control strategies against Aspergillus spoilage including biocontrol-prophylactic handling for better and durable maize production.

The postbiotic potential of Aspergillus oryzae - a narrative review

The filamentous fungus Aspergillus oryzae has a long tradition in East Asian food processing. It is therefore not surprising that in recent years fermentation products of A. oryzae have attracted attention in the emerging field of postbiotics. This review aims to provide a comprehensive summary of the potential postbiotic effects of fermentation products from A. oryzae, by discussing possible mechanisms of action against the background of the molecular composition determined so far. In particular, cell wall constituents, enzymes, extracellular polymeric substances, and various metabolites found in A. oryzae fermentation preparations are described in detail. With reference to the generally assumed key targets of postbiotics, their putative beneficial bioactivities in modulating the microbiota, improving epithelial barrier function, influencing immune responses, metabolic reactions and signaling through the nervous system are assessed. Drawing on existing literature and case studies, we highlight A. oryzae as a promising source of postbiotics, particularly in the context of animal health and nutrition. Challenges and opportunities in quality control are also addressed, with a focus on the necessity for standardized methods to fully harness the potential of fungal-based postbiotics. Overall, this article sheds light on the emerging field of A. oryzae-derived postbiotics and emphasizes the need for further research to fully realize their therapeutic potential.

Application and antagonistic mechanisms of atoxigenic Aspergillus strains for the management of fungal plant diseases

This review covers, for the first time, all methods based on the use of Aspergillus strains as biocontrol agents for the management of plant diseases caused by fungi and oomycetes. Atoxigenic Aspergillus strains have been screened in a variety of hosts, such as peanuts, maize kernels, and legumes, during the preharvest and postharvest stages. These strains have been screened against a wide range of pathogens, such as Fusarium, Phytophthora, and Pythium species, suggesting a broad applicability spectrum. The highest efficacies were generally observed when using non-toxigenic Aspergillus strains for the management of mycotoxin-producing Aspergillus strains. The modes of action included the synthesis of antifungal metabolites, such as kojic acid and volatile organic compounds (VOCs), secretion of hydrolytic enzymes, competition for space and nutrients, and induction of disease resistance. Aspergillus strains degraded Sclerotinia sclerotiorum sclerotia, showing high control efficacy against this pathogen. Collectively, although two Aspergillus strains have been commercialized for aflatoxin degradation, a new application of Aspergillus strains is emerging and needs to be optimized.

Analysis of composition and molecular characterization of mycobiota occurring on surface of cheese ripened in Dossena's mine

Accurate identification of the fungal community spontaneously colonizing food products, aged in natural and not controlled environments, provides information about potential mycotoxin risk associated with its consumption. Autochthonous mycobiota colonizing cheese aging in Dossena mines, was investigated and characterized by two approaches: microbial isolations and metabarcoding. Microbial isolations and metabarcoding analysis were conducted on cheese samples, obtained by four batches, produced in four different seasons of the year, aged for 90 and 180 days, by five dairy farms. The two approaches, with different taxonomical resolution power, highlighted Penicillium biforme among filamentous fungi, collected from 58 out of 68 cheeses, and Debaryomyces hansenii among yeasts, as the most abundant species (31 ÷ 65%), none representing a health risk for human cheese consumption. Shannon index showed that the richness of mycobiota increases after 180 days of maturation. Beta diversity analysis highlighted significant differences in composition of mycobiota of cheese produced by different dairy farms and aged for different durations. Weak negative growth interaction between P. biforme and Aspergillus westerdijkiae by in vitro analysis was observed leading to hypothesize that a reciprocal control is possible, also affected by natural environmental conditions, possibly disadvantageous for the last species.

Evaluation of mycotoxins, mycobiota and toxigenic fungi in the traditional medicine Radix Dipsaci

Medicinal herbs have been increasingly used for therapeutic purposes against a diverse range of human diseases worldwide. However, inevitable contaminants, including mycotoxins, in medicinal herbs can cause serious problems for humans despite their health benefits. The increasing consumption of medicinal plants has made their use a public health problem due to the lack of effective surveillance of the use, efficacy, toxicity, and quality of these natural products. Radix Dipsaci is commonly utilized in traditional Chinese medicine and is susceptible to contamination with mycotoxins. Here, we evaluated the mycotoxins, mycobiota and toxigenic fungi in the traditional medicine Radix Dipsaci. A total of 28 out of 63 Radix Dipsaci sample batches (44.4%) were found to contain mycotoxins. Among the positive samples, the contamination levels of AFB1, AFG1, AFG2, and OTA in the positive samples ranged from 0.52 to 32.13 μg/kg, 5.14 to 20.05 μg/kg, 1.52 to 2.33 μg/kg, and 1.81 to 19.43 μg/kg respectively, while the concentrations of ZEN and T-2 were found to range from 2.85 to 6.33 μg/kg and from 2.03 to 2.53 μg/kg, respectively. More than 60% of the contaminated samples were combined with multiple mycotoxins. Fungal diversity and community were altered in the Radix Dipsaci contaminated with various mycotoxins. The abundance of Aspergillus and Fusarium increased in the Radix Dipsaci contaminated with aflatoxins (AFs) and ZEN. A total of 95 strains of potentially toxigenic fungi were isolated from the Radix Dipsaci samples contaminated with mycotoxins, predominantly comprising Aspergillus (73.7%), Fusarium (20.0%), and Penicillium (6.3%). Through morphological identification, molecular identification, mycotoxin synthase gene identification and toxin production verification, we confirmed that AFB1 and AFG1 primarily derive from Aspergillus flavus, OTA primarily derives from Aspergillus westerdijkiae, ZEN primarily derives from Fusarium oxysporum, and T-2 primarily derives from Fusarium graminearum in Radix Dipsaci. These data can facilitate our comprehension of prevalent toxigenic fungal species and contamination levels in Chinese herbal medicine, thereby aiding the establishment of effective strategies for prevention, control, and degradation to mitigate the presence of fungi and mycotoxins in Chinese herbal medicine.

Optimization and Validation of a Cheaper, Safer, and More Sustainable Methodology for Aflatoxins Determination in Rich-Lipidic Matrices (Pistachio Nuts) Using Deep Eutectic Solvent Extraction and UHPLC-FLD Analysis

Aflatoxins pose a major health concern and require strict monitoring in food products. Existing methods rely on hazardous organic solvents for extraction, prompting the development of a greener alternative. This study explores deep eutectic solvents (DESs) for aflatoxin extraction from pistachios, a valuable food product prone to aflatoxin contamination. The proposed method utilizes DES extraction followed by solid-phase extraction cleanup and ultrahigh-performance liquid chromatography coupled with fluorescence detector analysis. Recovery rates ranged from 85.5 to 99.1% for pistachios spiked with 1-8 ng/g aflatoxins, in compliance with EU regulations, with coefficients of variation less than 2.94%. The method demonstrates good sensitivity with limits of detection and quantification in the range of 0.02-0.22 ng/g and 0.05-0.72 ng/g, respectively. Greenness assessment using AGREEPrep and White Analytical Chemistry metrics confirms its environmental sustainability. This approach offers a promising, safer, and more eco-friendly alternative for aflatoxin extraction from complex food matrices like pistachios.

Comparative analysis of the genomes and aflatoxin production patterns of three species within the Aspergillus section Flavi reveals an undescribed chemotype and habitat-specific genetic traits

Aflatoxins are the most dangerous mycotoxins for food safety. They are mainly produced by Aspergillus flavus, A. parasiticus, and A. minisclerotigenes. The latter, an understudied species, was the main culprit for outbreaks of fatal aflatoxicosis in Kenya in the past. To determine specific genetic characteristics of these Aspergillus species, their genomes are comparatively analyzed. Differences reflecting the typical habitat are reported, such as an increased number of carbohydrate-active enzymes, including enzymes for lignin degradation, in the genomes of A. minisclerotigenes and A. parasiticus. Further, variations within the aflatoxin gene clusters are described, which are related to different chemotypes of aflatoxin biosynthesis. These include a substitution within the aflL gene of the A. parasiticus isolate, which leads to the translation of a stop codon, thereby switching off the production of the group 1 aflatoxins B1 and G1. In addition, we demonstrate that the inability of the A. minisclerotigenes isolates to produce group G aflatoxins is associated with a 2.2 kb deletion within the aflF and aflU genes. These findings reveal a relatively high genetic homology among the three Aspergillus species investigated. However, they also demonstrate consequential genetic differences that have an important impact on risk-assessment and food safety.

Rapid Detection of Aflatoxins in Ground Maize Using Near Infrared Spectroscopy

Aflatoxins are carcinogenic mycotoxins that may contaminate many crops and more especially maize. To protect consumers from these contaminants, many countries set up low regulatory thresholds of few µg/kg. The control of food requires time-consuming analysis for which sampling is a key step. It would therefore of key sanitary and economic relevance to develop rapid, sensitive and accurate methods that could even be applied on line at harvest, to identify batches to be excluded as soon as possible. In this study, we analyzed more than 500 maize samples taken at harvest during 3 years for their aflatoxin contamination using HPLC-MS. Among them, only 7% were contaminated but sometimes at levels largely exceeding European regulations. We demonstrate that Near InfraRed Spectroscopy (NIRS) could be of great help to classify cereal samples according to their level of aflatoxin contamination (below or higher than E.U. regulation). To build the model, all AF contaminated samples as well as an equivalent number of AF free samples were used. NIRS performance was not sufficient to quantify the toxins with adequate precision. However, its ability to discriminate naturally contaminated maize samples according to their level of contamination with aflatoxins in relation to European regulations using a quadratic PCA-DA model was excellent. Accuracy of the model was 97.4% for aflatoxin B1 and 100% for total aflatoxins.

Maize Aspergillus section Flavi isolate diversity may be distinct from that of soil and subsequently the source of aflatoxin contamination

Aspergillus section Flavi (Flavi) is a diverse group of fungal species whose common members include A. flavus and A. parasiticus. These are well-known for the production of aflatoxin (AF) B and G and other toxic metabolites, like cyclopiazonic acid (CPA). They are saprophytic soil dwellers and also become crop opportunistic epiphytes. The consequence is contamination of the crop with mycotoxins, such as carcinogenic AF. We investigated the Flavi community structure of maize and that of their surrounding soil, including their mycotoxigenicity. Furthermore, we investigated the link of the maize Flavi diversity with preharvest maize AF levels. The study was carried out in four selected districts of Zambia, in a low rainfall zone. The Flavi characterisation was triphasic, involving morphological (colony colour and sclerotia formation), metabolic (AF and CPA production) and genetic (calmodulin gene polymorphism) analyses. Flavi abundance was determined by dilution plate technique on modified rose Bengal agar. Results showed that Flavi communities on maize and in soil differed. Maize had a higher Flavi species diversity than soil. A. parasiticus dominated the soil community by frequency of field appearance (85%), while maize was dominated by A. minisclerotigenes (45%). CPA-producers with or without AF production dominated the maize (65%) while producers of only AF (B/G) dominated the soil (88%). The ratio between maize A. parasiticus and A. minisclerotigenes abundance seemed to have had a bearing on the levels of AF in maize, with a ratio close to 1:1 having higher levels than a pure community of either A. parasiticus or A. minisclerotigenes.

What are the 100 most cited fungal genera?

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Błaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilański P, Bradley CA, Bubner B, Burgess TI, Buyck B, Čadež N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

Divergent Aspergillus flavus corn population is composed of prolific conidium producers: Implications for saprophytic disease cycle

The ascomycete fungus Aspergillus flavus infects and contaminates corn, peanuts, cottonseed, and tree nuts with toxic and carcinogenic aflatoxins. Subdivision between soil and host plant populations suggests that certain A. flavus strains are specialized to infect peanut, cotton, and corn despite having a broad host range. In this study, the ability of strains isolated from corn and/or soil in 11 Louisiana fields to produce conidia (field inoculum and male gamete) and sclerotia (resting bodies and female gamete) was assessed and compared with genotypic single-nucleotide polymorphism (SNP) differences between whole genomes. Corn strains produced upward of 47× more conidia than strains restricted to soil. Conversely, corn strains produced as much as 3000× fewer sclerotia than soil strains. Aspergillus flavus strains, typified by sclerotium diameter (small S-strains, <400 μm; large L-strains, >400 μm), belonged to separate clades. Several strains produced a mixture (M) of S and L sclerotia, and an intermediate number of conidia and sclerotia, compared with typical S-strains (minimal conidia, copious sclerotia) and L-strains (copious conidia, minimal sclerotia). They also belonged to a unique phylogenetic mixed (M) clade. Migration from soil to corn positively correlated with conidium production and negatively correlated with sclerotium production. Genetic differences correlated with differences in conidium and sclerotium production. Opposite skews in female (sclerotia) or male (conidia) gametic production by soil or corn strains, respectively, resulted in reduced effective breeding population sizes when comparing male:female gamete ratio with mating type distribution. Combining both soil and corn populations increased the effective breeding population, presumably due to contribution of male gametes from corn, which fertilize sclerotia on the soil surface. Incongruencies between aflatoxin clusters, strain morphotype designation, and whole genome phylogenies suggest a history of sexual reproduction within this Louisiana population, demonstrating the importance of conidium production, as infectious propagules and as fertilizers of the A. flavus soil population.

Identification of Food Spoilage Fungi Using MALDI-TOF MS: Spectral Database Development and Application to Species Complex

Fungi, including filamentous fungi and yeasts, are major contributors to global food losses and waste due to their ability to colonize a very large diversity of food raw materials and processed foods throughout the food chain. In addition, numerous fungal species are mycotoxin producers and can also be responsible for opportunistic infections. In recent years, MALDI-TOF MS has emerged as a valuable, rapid and reliable asset for fungal identification in order to ensure food safety and quality. In this context, this study aimed at expanding the VITEK® MS database with food-relevant fungal species and evaluate its performance, with a specific emphasis on species differentiation within species complexes. To this end, a total of 380 yeast and mold strains belonging to 51 genera and 133 species were added into the spectral database including species from five species complexes corresponding to Colletotrichum acutatum, Colletotrichum gloeosporioides, Fusarium dimerum, Mucor circinelloides complexes and Aspergillus series nigri. Database performances were evaluated by cross-validation and external validation using 78 fungal isolates with 96.55% and 90.48% correct identification, respectively. This study also showed the capacity of MALDI-TOF MS to differentiate closely related species within species complexes and further demonstrated the potential of this technique for the routine identification of fungi in an industrial context.

Comprehensive Review of Aflatoxin and Ochratoxin A Dynamics: Emergence, Toxicological Impact, and Advanced Control Strategies

Filamentous fungi exhibit remarkable adaptability to diverse substrates and can synthesize a plethora of secondary metabolites. These metabolites, produced in response to environmental stimuli, not only confer selective advantages but also encompass potentially deleterious mycotoxins. Mycotoxins, exemplified by those originating from Alternaria, Aspergillus, Penicillium, and Fusarium species, represent challenging hazards to both human and animal health, thus warranting stringent regulatory control. Despite regulatory frameworks, mycotoxin contamination remains a pressing global challenge, particularly within cereal-based matrices and their derived by-products, integral components of animal diets. Strategies aimed at mitigating mycotoxin contamination encompass multifaceted approaches, including biological control modalities, detoxification procedures, and innovative interventions like essential oils. However, hurdles persist, underscoring the imperative for innovative interventions. This review elucidated the prevalence, health ramifications, regulatory paradigms, and evolving preventive strategies about two prominent mycotoxins, aflatoxins and ochratoxin A. Furthermore, it explored the emergence of new fungal species, and biocontrol methods using lactic acid bacteria and essential mustard oil, emphasizing their efficacy in mitigating fungal spoilage and mycotoxin production. Through an integrative examination of these facets, this review endeavored to furnish a comprehensive understanding of the multifaceted challenges posed by mycotoxin contamination and the emergent strategies poised to ameliorate its impact on food and feed safety.

Molecular and aflatoxigenicity analyses of Aspergillus flavus isolates indigenous to grain corn in Malaysia; potentials for biological control

AIMS

The present work aimed to distinguish the indigenous Aspergillus flavus isolates obtained from the first (pioneer) grain corn farms in Terengganu, Malaysia, into aflatoxigenic and non-aflatoxigenic by molecular and aflatoxigenicity analyses, and determine the antagonistic capability of the non-aflatoxigenic isolates against aflatoxigenic counterparts and their aflatoxin production in vitro.

METHODS AND RESULTS

Seven A. flavus isolates previously obtained from the farms were characterized molecularly and chemically. All isolates were examined for the presence of seven aflatoxin biosynthesis genes, and their aflatoxigenicity was confirmed using high performance liquid chromatography with fluorescence detector. Phylogenetic relationships of all isolates were tested using ITS and β-tubulin genes. Of the seven isolates, two were non-aflatoxigenic, while the remaining were aflatoxigenic based on the presence of all aflatoxin biosynthesis genes tested and the productions of aflatoxins B1 and B2. All isolates were also confirmed as A. flavus following phylogenetic analysis. The indigenous non-aflatoxigenic isolates were further examined for their antagonistic potential against aflatoxigenic isolates on 3% grain corn agar. Both non-aflatoxigenic isolates significantly reduced AFB1 production of the aflatoxigenic isolates.

CONCLUSION

The indigenous non-aflatoxigenic A. flavus strains identified in the present work were effective in controlling the aflatoxin production by the aflatoxigenic A. flavus isolates in vitro and can be utilized for in situ testing.

The Biosynthesis, Structure Diversity and Bioactivity of Sterigmatocystins and Aflatoxins: A Review

Sterigmatocystins and aflatoxins are a group of mycotoxins mainly isolated from fungi of the genera Aspergillus. Since the discovery of sterigmatocystins in 1954 and aflatoxins in 1961, many scholars have conducted a series of studies on their structural identification, synthesis and biological activities. Studies have shown that sterigmatocystins and aflatoxins have a wide range of biological activities such as antitumour, antibacterial, anti-inflammatory, antiplasmodial, etc. The sterigmatocystins and aflatoxins had been shown to be hepatotoxic and nephrotoxic in animals. This review attempts to give a comprehensive summary of progress on the chemical structural features, synthesis, and bioactivity of sterigmatocystins and aflatoxins reported from 1954 to April 2024. A total of 72 sterigmatocystins and 20 aflatoxins are presented in this review. This paper reviews the chemical diversity and potential activity and toxicity of sterigmatocystins and aflatoxins, enhances the understanding of sterigmatocystins and aflatoxins that adversely affect humans and animals, and provides ideas for their prevention, research and development.

Sporulation and Dispersal of the Biological Control Agent Aspergillus flavus AF36 Under Field Conditions

Aflatoxins are carcinogens produced by the fungi Aspergillus flavus and A. parasiticus that contaminate pistachio crops. International markets reject pistachio when aflatoxins exceed permitted maximum levels. Releasing the atoxigenic strain AF36 of A. flavus is the leading aflatoxin pre-harvest control method. The product AF36 Prevail, sorghum grains coated with AF36 propagules, has been used in California since 2017. However, a high percentage of grains of the Prevail fail to sporulate in orchards. Here, the effect of soil moisture on the percentage of AF36 product grains sporulating (SG) and the quantity of spores per grain using a sporulation index (SI) was determined. Under controlled conditions, SG was higher than 85% when soil moisture was 13% or more, and SI increased with increasing soil moisture from 8.4 to 21%. The highest AF36 sporulation occurred near the micro-sprinklers when the grains were not impacted by the irrigation water drops. Arthropod predation was responsible for lost product grains, which was more pronounced in non-tilled soil than in tilled soil. Dispersal of the AF36 spores decreased markedly with the height and distance from the inoculum source, following a pattern of diffusion equations. However, AF36 spores easily reached canopies of pistachios located 10 m from the inoculum source. Our results indicate that AF36 Prevail should be applied close to the irrigation line in the moist soil area but avoiding the areas where excess irrigation causes water accumulation. The biocontrol of aflatoxins in California's pistachio production areas was optimized by improving the field realization of the biological control agent.

Aspergillus flavus pangenome (AflaPan) uncovers novel aflatoxin and secondary metabolite associated gene clusters

BACKGROUND

Aspergillus flavus is an important agricultural and food safety threat due to its production of carcinogenic aflatoxins. It has high level of genetic diversity that is adapted to various environments. Recently, we reported two reference genomes of A. flavus isolates, AF13 (MAT1-2 and highly aflatoxigenic isolate) and NRRL3357 (MAT1-1 and moderate aflatoxin producer). Where, an insertion of 310 kb in AF13 included an aflatoxin producing gene bZIP transcription factor, named atfC. Observations of significant genomic variants between these isolates of contrasting phenotypes prompted an investigation into variation among other agricultural isolates of A. flavus with the goal of discovering novel genes potentially associated with aflatoxin production regulation. Present study was designed with three main objectives: (1) collection of large number of A. flavus isolates from diverse sources including maize plants and field soils; (2) whole genome sequencing of collected isolates and development of a pangenome; and (3) pangenome-wide association study (Pan-GWAS) to identify novel secondary metabolite cluster genes.

RESULTS

Pangenome analysis of 346 A. flavus isolates identified a total of 17,855 unique orthologous gene clusters, with mere 41% (7,315) core genes and 59% (10,540) accessory genes indicating accumulation of high genomic diversity during domestication. 5,994 orthologous gene clusters in accessory genome not annotated in either the A. flavus AF13 or NRRL3357 reference genomes. Pan-genome wide association analysis of the genomic variations identified 391 significant associated pan-genes associated with aflatoxin production. Interestingly, most of the significantly associated pan-genes (94%; 369 associations) belonged to accessory genome indicating that genome expansion has resulted in the incorporation of new genes associated with aflatoxin and other secondary metabolites.

CONCLUSION

In summary, this study provides complete pangenome framework for the species of Aspergillus flavus along with associated genes for pathogen survival and aflatoxin production. The large accessory genome indicated large genome diversity in the species A. flavus, however AflaPan is a closed pangenome represents optimum diversity of species A. flavus. Most importantly, the newly identified aflatoxin producing gene clusters will be a new source for seeking aflatoxin mitigation strategies and needs new attention in research.

A comprehensive review of mycotoxins: Toxicology, detection, and effective mitigation approaches

Mycotoxins, harmful compounds produced by fungal pathogens, pose a severe threat to food safety and consumer health. Some commonly produced mycotoxins such as aflatoxins, ochratoxin A, fumonisins, trichothecenes, zearalenone, and patulin have serious health implications in humans and animals. Mycotoxin contamination is particularly concerning in regions heavily reliant on staple foods like grains, cereals, and nuts. Preventing mycotoxin contamination is crucial for a sustainable food supply. Chromatographic methods like thin layer chromatography (TLC), gas chromatography (GC), high-performance liquid chromatography (HPLC), and liquid chromatography coupled with a mass spectrometer (LC/MS), are commonly used to detect mycotoxins; however, there is a need for on-site, rapid, and cost-effective detection methods. Currently, enzyme-linked immunosorbent assays (ELISA), lateral flow assays (LFAs), and biosensors are becoming popular analytical tools for rapid detection. Meanwhile, preventing mycotoxin contamination is crucial for food safety and a sustainable food supply. Physical, chemical, and biological approaches have been used to inhibit fungal growth and mycotoxin production. However, new strains resistant to conventional methods have led to the exploration of novel strategies like cold atmospheric plasma (CAP) technology, polyphenols and flavonoids, magnetic materials and nanoparticles, and natural essential oils (NEOs). This paper reviews recent scientific research on mycotoxin toxicity, explores advancements in detecting mycotoxins in various foods, and evaluates the effectiveness of innovative mitigation strategies for controlling and detoxifying mycotoxins.

Biocontrol activities of yeasts or lactic acid bacteria isolated from Robusta coffee against Aspergillus carbonarius growth and ochratoxin A production in vitro

Biocontrol Agents (BCAs) can be an eco-friendly alternative to fungicides to reduce the contamination with mycotoxigenic fungi on coffee. In the present study, different strains of bacteria and yeasts were isolated from Ivorian Robusta coffee. Their ability to reduce fungal growth and Ochratoxin A (OTA) production during their confrontation against Aspergillus carbonarius was screened on solid media. Some strains were able to reduce growth and OTA production by 85 % and 90 % and were molecularly identified as two yeasts, Rhodosporidiobolus ruineniae and Meyerozyma caribbica. Subsequent tests on liquid media with A. carbonarius or solely with OTA revealed adhesion of R. ruineniae to the mycelium of A. carbonarius through Scanning Electron Microscopy, and an OTA adsorption efficiency of 50 %. For M. caribbica potential degradation of OTA after 24 h incubation was observed. Both yeasts could be potential BCAs good candidates for Ivorian Robusta coffee protection against A. carbonarius and OTA contamination.

Comprehensive Insights into Ochratoxin A: Occurrence, Analysis, and Control Strategies

Ochratoxin A (OTA) is a toxic mycotoxin produced by some mold species from genera Penicillium and Aspergillus. OTA has been detected in cereals, cereal-derived products, dried fruits, wine, grape juice, beer, tea, coffee, cocoa, nuts, spices, licorice, processed meat, cheese, and other foods. OTA can induce a wide range of health effects attributable to its toxicological properties, including teratogenicity, immunotoxicity, carcinogenicity, genotoxicity, neurotoxicity, and hepatotoxicity. OTA is not only toxic to humans but also harmful to livestock like cows, goats, and poultry. This is why the European Union and various countries regulate the maximum permitted levels of OTA in foods. This review intends to summarize all the main aspects concerning OTA, starting from the chemical structure and fungi that produce it, its presence in food, its toxicity, and methods of analysis, as well as control strategies, including both fungal development and methods of inactivation of the molecule. Finally, the review provides some ideas for future approaches aimed at reducing the OTA levels in foods.

The Gene vepN Regulated by Global Regulatory Factor veA That Affects Aflatoxin Production, Morphological Development and Pathogenicity in Aspergillus flavus

Velvet (VeA), a light-regulated protein that shuttles between the cytoplasm and the nucleus, serves as a key global regulator of secondary metabolism in various Aspergillus species and plays a pivotal role in controlling multiple developmental processes. The gene vepN was chosen for further investigation through CHIP-seq analysis due to significant alterations in its interaction with VeA under varying conditions. This gene (AFLA_006970) contains a Septin-type guanine nucleotide-binding (G) domain, which has not been previously reported in Aspergillus flavus (A. flavus). The functional role of vepN in A. flavus was elucidated through the creation of a gene knockout mutant and a gene overexpression strain using a well-established dual-crossover recombinational technique. A comparison between the wild type (WT) and the ΔvepN mutant revealed distinct differences in morphology, reproductive capacity, colonization efficiency, and aflatoxin production. The mutant displayed reduced growth rate; dispersion of conidial heads; impaired cell wall integrity; and decreased sclerotia formation, colonization capacity, and aflatoxin levels. Notably, ΔvepN exhibited complete growth inhibition under specific stress conditions, highlighting the essential role of vepN in A. flavus. This study provides evidence that vepN positively influences aflatoxin production, morphological development, and pathogenicity in A. flavus.

Phylogenomics reveals extensive misidentification of fungal strains from the genus Aspergillus

Modern taxonomic classification is often based on phylogenetic analyses of a few molecular markers, although single-gene studies are still common. Here, we leverage genome-scale molecular phylogenetics (phylogenomics) of species and populations to reconstruct evolutionary relationships in a dense data set of 710 fungal genomes from the biomedically and technologically important genus Aspergillus. To do so, we generated a novel set of 1,362 high-quality molecular markers specific for Aspergillus and provided profile Hidden Markov Models for each, facilitating their use by others. Examining the resulting phylogeny helped resolve ongoing taxonomic controversies, identified new ones, and revealed extensive strain misidentification (7.59% of strains were previously misidentified), underscoring the importance of population-level sampling in species classification. These findings were corroborated using the current standard, taxonomically informative loci. These findings suggest that phylogenomics of species and populations can facilitate accurate taxonomic classifications and reconstructions of the Tree of Life.IMPORTANCEIdentification of fungal species relies on the use of molecular markers. Advances in genomic technologies have made it possible to sequence the genome of any fungal strain, making it possible to use genomic data for the accurate assignment of strains to fungal species (and for the discovery of new ones). We examined the usefulness and current limitations of genomic data using a large data set of 710 publicly available genomes from multiple strains and species of the biomedically, agriculturally, and industrially important genus Aspergillus. Our evolutionary genomic analyses revealed that nearly 8% of publicly available Aspergillus genomes are misidentified. Our work highlights the usefulness of genomic data for fungal systematic biology and suggests that systematic genome sequencing of multiple strains, including reference strains (e.g., type strains), of fungal species will be required to reduce misidentification errors in public databases.

Structure of Aspergillus flavus populations associated with maize in Greece, Spain, and Serbia: Implications for aflatoxin biocontrol on a regional scale

Aspergillus flavus is the most frequently identified producer of aflatoxins. Non-aflatoxigenic members of the A. flavus L strains are used in various continents as active ingredients of bioprotectants directed at preventing aflatoxin contamination by competitive displacement of aflatoxin producers. The current research examined the genetic diversity of A. flavus L strain across southern Europe to gain insights into the population structure and evolution of this species and to evaluate the prevalence of genotypes closely related to MUCL54911, the active ingredient of AF-X1. A total of 2173L strain isolates recovered from maize collected across Greece, Spain, and Serbia in 2020 and 2021 were subjected to simple sequence repeat (SSR) genotyping. The analysis revealed high diversity within and among countries and dozens of haplotypes shared. Linkage disequilibrium analysis indicated asexual reproduction and clonal evolution of A. flavus L strain resident in Europe. Moreover, haplotypes closely related to MUCL54911 were found to belong to the same vegetative compatibility group (VCG) IT006 and were relatively common in all three countries. The results indicate that IT006 is endemic to southern Europe and may be utilized as an aflatoxin mitigation tool for maize across the region without concern for potential adverse impacts associated with the introduction of an exotic microorganism.