Occurrence of Fusarium Mycotoxins and Their Modified Forms in Forage Maize Cultivars

Efficacy of Lamium album as a natural fungicide: impact on seed germination, ergosterol, and mycotoxins in Fusarium culmorum-infected wheat seedlings

Fusarium culmorum is a major wheat pathogen, and its secondary metabolites (mycotoxins) cause damage to plants, animals, and human health. In the era of sustainable agriculture, eco-friendly methods of prevention and control are constantly needed. The use of plant extracts as biocontrol agents has gained popularity as they are a source of active substances that play a crucial role in fighting against phytopathogens. This study evaluated the impact of Lamium album on wheat seed germination and seedling growth. In a pot experiment, the effect of L. album on wheat seedlings artificially inoculated with F. culmorum was evaluated by measuring seedling growth parameters, and by using chromatographic methods, ergosterol and mycotoxins levels were analyzed. The results showed that the phytotoxic effect of L. album flower extracts on wheat seed germination and seedling growth was concentration dependent. The radicle length was also reduced compared to the control; however, L. album did not significantly affect the dry weight of the radicle. A slight phytotoxic effect on seed germination was observed, but antifungal effects on artificially infected wheat seedlings were also confirmed with the reduction of ergosterol level and mycotoxins accumulation in the roots and leaves after 21 days of inoculation. F. culmorum DNA was identified in the control samples only. Overall, this study is a successful in planta study showing L. album flower extract protection of wheat against the pathogen responsible for Fusarium crown and root rot. Further research is essential to study the effects of L. album extracts on key regulatory genes for mycotoxin biosynthetic pathways.

Improvement of the sensitivity of lateral flow systems for detecting mycotoxins: Up-to-date strategies and future perspectives

Mycotoxins are dangerous human and animal health-threatening secondary fungal metabolites that can be found in various food and agricultural products. Several countries have established regulations to restrict their presence in food and agricultural products destined for human and animal consumption. Consequently, the need to develop highly sensitive and smart detection systems was recognized worldwide. Lateral flow assay possesses the advantages of easy operation, rapidity, stability, accuracy, and specificity, and it plays an important role in the detection of mycotoxins. Nevertheless, strategies to comprehensively improve the sensitivity of lateral flow assay to mycotoxins in food have rarely been highlighted and discussed. In this article, a comprehensive overview was presented on the application of lateral flow assay in mycotoxin detection in food samples by highlighting the principle of lateral flow assay, presenting a detailed discussion on various analytical performance-improvement strategies, such as the development of high-affinity recognition reagents, immunogen immobilization methods, and signal amplification. Additionally, a detailed discussion on the various signal analyzers and interpretation approaches was provided. Finally, current hurdles and future perspectives on the application of lateral flow assay in the detection of mycotoxins were discussed.

Global distribution, toxicity to humans and animals, biodegradation, and nutritional mitigation of deoxynivalenol: A review

Deoxynivalenol (DON) is one of the main types of B trichothecenes, and it causes health-related issues in humans and animals and imposes considerable challenges to food and feed safety globally each year. This review investigates the global hazards of DON, describes the occurrence of DON in food and feed in different countries, and systematically uncovers the mechanisms of the various toxic effects of DON. For DON pollution, many treatments have been reported on the degradation of DON, and each of the treatments has different degradation efficacies and degrades DON by a distinct mechanism. These treatments include physical, chemical, and biological methods and mitigation strategies. Biodegradation methods include microorganisms, enzymes, and biological antifungal agents, which are of great research significance in food processing because of their high efficiency, low environmental hazards, and drug resistance. And we also reviewed the mechanisms of biodegradation methods of DON, the adsorption and antagonism effects of microorganisms, and the different chemical transformation mechanisms of enzymes. Moreover, nutritional mitigation including common nutrients (amino acids, fatty acids, vitamins, and microelements) and plant extracts was discussed in this review, and the mitigation mechanism of DON toxicity was elaborated from the biochemical point of view. These findings help explore various approaches to achieve the best efficiency and applicability, overcome DON pollution worldwide, ensure the sustainability and safety of food processing, and explore potential therapeutic options with the ability to reduce the deleterious effects of DON in humans and animals.

Alternaria Mycotoxins Analysis and Exposure Investigation in Ruminant Feeds

Alternaria mycotoxins are a class of important, agriculture-related hazardous materials, and their contamination in ruminant feeds and products might bring severe toxic effects to animals and even human beings. To control these hazardous compounds, a reliable and sensitive LC-MS/MS (liquid chromatography-tandem mass spectrometry) method was established for simultaneous determination of six target Alternaria mycotoxins in ruminant feeds, including ALT (Altenuene), AME (Alternariol Monomethyl Ether), AOH (Alternariol), ATX-Ι (Altertoxins I), TeA (Tenuazonic Acid), and TEN (Tentoxin). This developed analytical method was used for the determination of the presence of these substances in cattle and sheep feeds in Xinjiang Province, China. The results revealed that Alternaria mycotoxins are ubiquitously detected in feed samples. Especially, AME, AOH, TeA, and TEN are the most frequently found mycotoxins with a positive rate over 40% and a concentration range of 4~551 µg/kg. The proposed method could be applied for exposure investigation of Alternaria mycotoxins in ruminant feeds and for the reduction in the health risk to animals and even consumers.

Relevance of Zearalenone and its modified forms in bakery products

Zearalenone is a frequently occurring and well-known mycotoxin developed in cereals before and during the harvest period by Fusarium spp. mainly in maize and wheat. In addition to the main form, various modified forms (phase I and II metabolites) were detected, in some cases in high amounts. These modified forms can be harmful for human health due to their different toxicity, which can be much higher compared to the parent toxin. In addition, the parent toxin can be cleaved from the phase I and II metabolites during digestion. A risk of correlated and additive adverse effects of the metabolites of ZEN phase I and II in humans and animals is evident. ZEN is considered in many studies on its occurrence in grain-based foods and some studies are dedicated to the behavior of ZEN during food processing. This is not the case for the ZEN phase I and II metabolites, which are only included in a few occurrence reports. Their effects during food processing is also only sporadically addressed in studies to date. In addition to the massive lack of data on the occurrence and behavior of ZEN modified forms, there is also a lack of comprehensive clarification of the toxicity of the numerous different ZEN metabolites detected to date. Finally, studies on the fate during digestion of the relevant ZEN metabolites will be important in the future to further clarify their relevance in processed foods such as bakery products.

Novel insights into versatile nanomaterials integrated bioreceptors toward zearalenone ultrasensitive discrimination

Detrimental contamination of zearalenone (ZEN) in crops and foodstuffs has drawn intensive public attention since it poses an ongoing threat to global food security and human health. Highly sensitive and rapid response ZEN trace analysis suitable for complex matrices at different processing stages is an indispensable part of food production. Conventional detection methods for ZEN encounter many deficiencies and demerits such as sophisticated equipment and heavy labor intensity. Alternatively, the nanomaterial-based biosensors featured with high sensitivity, portability, and miniaturization are springing up and emerging as superb substitutes to monitor ZEN in recent years. Herein, we predominantly devoted to overview the progress in the fabrication strategies and applications of various nanomaterial-based biosensors, highlighting rationales on sensing mechanisms, response types, and practical analytical performance. Synchronously, the versatile nanomaterials integrating with diverse recognition elements for augmenting sensing capabilities are emphasized. Finally, critical challenges and perspectives to expedite ZEN detection are outlooked.

Use of polypyrrole ferrite microparticles and liquid chromatography-mass spectrometry for testing natural grass contamination by multiclass mycotoxins

An analytical methodology based on the combination of dispersive magnetic solid-phase extraction (DMSPE) and liquid chromatography-mass spectrometry (LC-MS) is proposed to explore the occurrence of 13 mycotoxins (aflatoxins B₁, G₁, B₂, and G₂; deoxynivalenol; T-2 toxin; ochratoxin A; HT-2 toxin; enniatins A, A₁, B, and B₂; and beauvericin) and their derivatives in natural grass samples. Magnetic microparticles (Fe₃O₄) coated with polypyrrole (PPy) polymer were used in DMSPE sample treatment as adsorbent phase, and Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy have been used for its characterization. The experimental parameters influencing the adsorption and desorption steps of DMSPE have been optimized. Method validation has been carried out obtaining limits of quantification between 0.07 and 92 μg kg^-1 corresponding to enniatin B or A₁ and DON, respectively. A total of 83 natural grass samples from 8 dehesa farms were analysed. Enniatin B was found in all the samples (0.29 to 488 μg kg^-1 concentration range) followed by enniatin B₁ (92.8% of the samples) with a 0.12-137 μg kg^-1 concentration range. Moreover, co-occurrence of mycotoxins was studied and between 2 and 5 mycotoxins appeared simultaneously in 97.6% of the samples. Distribution of the contamination according to natural grass location was also investigated.

Risk Assessment of Combined Exposure to Multiple Chemicals at the European Food Safety Authority: Principles, Guidance Documents, Applications and Future Challenges

Human health and animal health risk assessment of combined exposure to multiple chemicals use the same steps as single-substance risk assessment, namely problem formulation, exposure assessment, hazard assessment and risk characterisation. The main unique feature of combined RA is the assessment of combined exposure, toxicity and risk. Recently, the Scientific Committee of the European Food Safety Authority (EFSA) published two relevant guidance documents. The first one "Harmonised methodologies for the human health, animal health and ecological risk assessment of combined exposure to multiple chemicals" provides principles and explores methodologies for all steps of risk assessment together with a reporting table. This guidance supports also the default assumption that dose addition is applied for combined toxicity of the chemicals unless evidence for response addition or interactions (antagonism or synergism) is available. The second guidance document provides an account of the scientific criteria to group chemicals in assessment groups using hazard-driven criteria and prioritisation methods, i.e., exposure-driven and risk-based approaches. This manuscript describes such principles, provides a brief description of EFSA's guidance documents, examples of applications in the human health and animal health area and concludes with a discussion on future challenges in this field.

New perspectives in application of kidney biomarkers in mycotoxin induced nephrotoxicity, with a particular focus on domestic pigs

The gradual spread of Aspergilli worldwide is adding to the global shortage of food and is affecting its safe consumption. Aspergillus-derived mycotoxins, including aflatoxins and ochratoxin A, and fumonisins (members of the fusariotoxin group) can cause pathological damage to vital organs, including the kidney or liver. Although the kidney functions as the major excretory system in mammals, monitoring and screening for mycotoxin induced nephrotoxicity is only now a developmental area in the field of livestock feed toxicology. Currently the assessment of individual exposure to mycotoxins in man and animals is usually based on the analysis of toxin and/or metabolite contamination in the blood or urine. However, this requires selective and sensitive analytical methods (e.g., HPLC-MS/MS), which are time consuming and expensive. The toxicokinetic of mycotoxin metabolites is becoming better understood. Several kidney biomarkers are used successfully in drug development, however cost-efficient, and reliable kidney biomarkers are urgently needed for monitoring farm animals for early signs of kidney disease. β₂-microglobulin (β₂-MG) and N-acetyl-β-D-glucosaminidase (NAG) are the dominant biomarkers employed routinely in environmental toxicology research, while kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as effective markers to identify mycotoxin induced nephropathy. Pigs are exposed to mycotoxins due to their cereal-based diet and are particularly susceptible to Aspergillus mycotoxins. In addition to commonly used diagnostic markers for nephrotoxicity including plasma creatinine, NAG, KIM-1 and NGAL can be used in pigs. In this review, the currently available techniques are summarized, which are used for screening mycotoxin induced nephrotoxicity in farm animals. Possible approaches are considered, which could be used to detect mycotoxin induced nephropathy.

Recent Research on Fusarium Mycotoxins in Maize—A Review

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.—mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

Near-infrared spectroscopy to assess mycotoxins contamination and nutritional composition of maize marketed in South America, years 2020-2021

Mycotoxicological and nutritional analyses were conducted in maize from Argentina, Bolivia, Brazil (stratified by region), Colombia and Peru through near-infrared spectroscopy (NIRS) in 2020 and 2021. Concentrations of aflatoxin B1 (AFB1), fumonisins B1 + B2 (FBs), zearalenone (ZEN) and deoxynivalenol, in addition to water activity, crude protein (CP), ether extract (EE), starch and apparent metabolizable energy (AME) in poultry, were determined in 18,363 spectra (totalling 195,486 analyses). FBs were the most prevalent metabolites in South American maize, being detected in 91.6 and 91.9% of the samples; ZEN had the second highest positivity, 15.4 and 26.8%, followed by AFB1, 15.3 and 14.6% (2020 and 2021, respectively). FBs also had the highest incidence in Brazilian maize, 92.6 and 92.1%, followed by AFB1, 15.2 and 13.5%, and ZEN, 14.7 and 27.7% (2020 and 2021, respectively). Contamination with at least one mycotoxin was detected in 93.5% of the samples. The mycotoxins found co-contaminating the maize belong to the genera Fusarium and Aspergillus; FBs, followed by ZEN and AFB1, were the most prevalent toxins in the associations. Levels of water activity were below 0.70. Regarding chemical composition, CP presented the largest oscillation in relation to the mean in South American maize (both years). As for the Brazilian samples, the Southeast region showed the greatest positive variability in relation to the means for all evaluated parameters, followed by the Northeast region (excepting CP) in 2020; in 2021, the Central-West and Northeast regions had the highest levels of EE and AME. In both years, the South region presented lower levels in relation to the mean for most parameters. Data on prevalence, mycotoxicological contamination, storage conditions and nutritional quality of maize assist the decision-making process of raw material use. In this setting, NIRS suits the needs of the industry for providing information on multiple parameters in real time.

Deoxynivalenol Degradation by Various Microbial Communities and Its Impacts on Different Bacterial Flora

Deoxynivalenol, a mycotoxin that may present in almost all cereal products, can cause huge economic losses in the agriculture industry and seriously endanger food safety and human health. Microbial detoxifications using microbial consortia may provide a safe and effective strategy for DON mitigation. In order to study the interactions involving DON degradation and change in microbial flora, four samples from different natural niches, including a chicken stable (expJ), a sheep stable (expY), a wheat field (expT) and a horse stable (expM) were collected and reacted with purified DON. After being co-incubated at 30 °C with 130 rpm shaking for 96 h, DON was reduced by 74.5%, 43.0%, 46.7%, and 86.0% by expJ, expY, expT, and expM, respectively. After DON (0.8 mL of 100 μg/mL) was co-cultivated with 0.2 mL of the supernatant of each sample (i.e., suspensions of microbial communities) at 30 °C for 96 h, DON was reduced by 98.9%, 99.8%, 79.5%, and 78.9% in expJ, expY, expT, and expM, respectively, and was completely degraded after 8 days by all samples except of expM. DON was confirmed being transformed into de-epoxy DON (DOM-1) by the microbial community of expM. The bacterial flora of the samples was compared through 16S rDNA flux sequencing pre- and post the addition of DON. The results indicated that the diversities of bacterial flora were affected by DON. After DON treatment, the most abundant bacteria belong to Galbibacter (16.1%) and Pedobacter (8.2%) in expJ; Flavobacterium (5.9%) and Pedobacter (5.5%) in expY; f_Microscillaceae (13.5%), B1-7BS (13.4%), and RB41 (10.5%) in expT; and Acinetobacter (24.1%), Massilia (8.8%), and Arthrobacter (7.6%) in expM. This first study on the interactions between DON and natural microbial flora provides useful information and a methodology for further development of microbial consortia for mycotoxin detoxifications.

Cellobiose inhibits the release of deoxynivalenol from transformed deoxynivalenol-3-glucoside from Lactiplantibacillus plantarum

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The NMM.1 efficiently transformed deoxynivalenol-3-glucoside to deoxynivalenol.

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Deoxynivalenol-3-glucoside transformation preferred weak alkaline environments.

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Deoxynivalenol-3-glucoside down-regulated cellobiose metabolism of the NMM.1.

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Cellobiose could efficiently inhibit deoxynivalenol-3-glucoside transformation.

The masked mycotoxin deoxynivalenol-3-glucoside (D3G) has been reported to be a detoxification product in plants, but can be hydrolyzed into its toxic precursor, deoxynivalenol (DON). Herein, we reported that Lactiplantibacillus plantarum (L. plantarum) NMM.1, isolated from Inner Mongolia raw milk, can efficiently transform D3G to DON in a short time. The global transcriptome microarray profiling of L. plantarum NMM.1 revealed differential expression of genes related to the phosphotransferase system (PTS) when D3G was used as the sole carbohydrate source. By adding an exogenous carbon source, we found that cellobiose efficiently inhibited the conversion of D3G into its precursor toxin by L. plantarum NMM.1. Overall, substrate depletion studies, transcriptome analysis, and carbohydrate intervention studies of L. plantarum NMM.1 suggested that cellobiose could be used to prevent the transformation of D3G into its free native DON by L. plantarum, thereby preventing harm to the human body.

Deoxynivalenol and its modified forms: key enzymes, inter-individual and interspecies differences in metabolism

Deoxynivalenol (DON) and its modified forms, including DON-3-glucoside (DON-3G), pose a major agricultural and food safety issue in the world. Their metabolites are relatively well-characterized; however, their metabolizing enzymes have not been fully explored. UDP-glucuronosyltransferases, 3-O-acetyltransferase, and glutathione S-transferase are involved in the formation of DON-glucuronides, 3-acetyl-DON, and DON-glutathione, respectively. There are interindividual differences in the metabolism of these toxins, including variation with respect to sex. Furthermore, interspecies differences in DON metabolism have been revealed, including differences in the major metabolites of DON, the role of de-acetylation, and the hydrolysis of DON-3G. In this review, we summarized the major enzymes involved in metabolizing DON to its modified forms, focusing on the differences in metabolism of DON and its modified forms between individuals and species. This work provides important insight into the toxicity of DON and its derivatives in humans and animals, and provides scientific basis for the development of safer and more efficient biological detoxification methods.

The control of Fusarium growth and decontamination of produced mycotoxins by lactic acid bacteria

Global crop and food contamination with mycotoxins are one of the primary worldwide concerns, while there are several restrictions regarding approaching conventional physical and chemical mycotoxins decontamination methods due to nutrition loss, sensory attribute reduction in foods, chemical residual, inconvenient operation, high cost of equipment, and high energy consumption of some methods. In this regard, the overarching challenges of mycotoxin contamination in food and food crops require the development of biological decontamination strategies. Using certain lactic acid bacteria (LAB) as generally recognized safe (GRAS) compounds is one of the most effective alternatives due to their potential to release antifungal metabolites against various fungal factors species. This review highlights the potential applications of LAB as biodetoxificant agents and summarizes their decontamination activities against Fusarium growth and Fusarium mycotoxins released into food/feed. Firstly, the occurrence of Fusarium and the instrumental and bioanalytical methods for the analysis of mycotoxins were in-depth discussed. Upgraded knowledge on the biosynthesis pathway of mycotoxins produced by Fusarium offers new insightful ideas clarifying the function of these secondary metabolites. Moreover, the characterization of LAB metabolites and their impact on the decontamination of the mycotoxin from Fusarium, besides the main mechanisms of mycotoxin decontamination, are covered. While the thematic growth inhibition of Fusarium and decontamination of their mycotoxin by LAB is very complex, approaching certain lactic acid bacteria (LAB) is worth deeper investigations.

Deoxynivalenol: An Overview on Occurrence, Chemistry, Biosynthesis, Health Effects and Its Detection, Management, and Control Strategies in Food and Feed

Mycotoxins are fungi-produced secondary metabolites that can contaminate many foods eaten by humans and animals. Deoxynivalenol (DON), which is formed by Fusarium, is one of the most common occurring predominantly in cereal grains and thus poses a significant health risk. When DON is ingested, it can cause both acute and chronic toxicity. Acute signs include abdominal pain, anorexia, diarrhea, increased salivation, vomiting, and malaise. The most common effects of chronic DON exposure include changes in dietary efficacy, weight loss, and anorexia. This review provides a succinct overview of various sources, biosynthetic mechanisms, and genes governing DON production, along with its consequences on human and animal health. It also covers the effect of environmental factors on its production with potential detection, management, and control strategies.

A Preliminary Study to Classify Corn Silage for High or Low Mycotoxin Contamination by Using near Infrared Spectroscopy

Mycotoxins should be monitored in order to properly evaluate corn silage safety quality. In the present study, corn silage samples (n = 115) were collected in a survey, characterized for concentrations of mycotoxins, and scanned by a NIR spectrometer. Random Forest classification models for NIR calibration were developed by applying different cut-offs to classify samples for concentration (i.e., μg/kg dry matter) or count (i.e., n) of (i) total detectable mycotoxins; (ii) regulated and emerging Fusarium toxins; (iii) emerging Fusarium toxins; (iv) Fumonisins and their metabolites; and (v) Penicillium toxins. An over- and under-sampling re-balancing technique was applied and performed 100 times. The best predictive model for total sum and count (i.e., accuracy mean ± standard deviation) was obtained by applying cut-offs of 10,000 µg/kg DM (i.e., 96.0 ± 2.7%) or 34 (i.e., 97.1 ± 1.8%), respectively. Regulated and emerging Fusarium mycotoxins achieved accuracies slightly less than 90%. For the Penicillium mycotoxin contamination category, an accuracy of 95.1 ± 2.8% was obtained by using a cut-off limit of 350 µg/kg DM as a total sum or 98.6 ± 1.3% for a cut-off limit of five as mycotoxin count. In conclusion, this work was a preliminary study to discriminate corn silage for high or low mycotoxin contamination by using NIR spectroscopy.

Study on Contamination with Some Mycotoxins in Maize and Maize-Derived Foods

Crops can be contaminated by fungi which produce mycotoxins. Many fungal strains are responsible for producing varied mycotoxins. The research carried out so far has described over 400 different mycotoxins. They have chemical and physical properties that significantly differ, and they are produced by several different existing fungi. The intake of mycotoxins through food can be achieved directly, by feeding on contaminated food, or indirectly from foods of animal origin. The mycotoxin contamination of food and food products for certain animals is a phenomenon studied worldwide, in countries in Europe but also in Asia, Africa and America. The purpose of this study is to develop an evaluation of the mycotoxins prevalent in corn and corn-derived products produced in Romania. A total of 38 maize samples and 19 corn-derivative samples were investigated for the presence of mycotoxins specific to these products, such as deoxynivalenol, zearalenone and fumonisins. Fumonisins had the highest presence and zearalenone had the lowest. The limits determined for the three mycotoxins were always in accordance with legal regulations.

Biological Control of Fusarium culmorum, Fusarium graminearum and Fusarium poae by Antagonistic Yeasts

The genus Fusarium is considered to be one of the most pathogenic, phytotoxic and toxin-producing group of microorganisms in the world. Plants infected by these fungi are characterized by a reduced consumer and commercial value, mainly due to the contamination of crops with mycotoxins. Therefore, effective methods of reducing fungi of the genus Fusarium must be implemented already in the field before harvesting, especially with alternative methods to pesticides such as biocontrol. In this study we identified yeasts that inhibit the growth of the pathogenic fungi Fusarium culmorum, F. graminearum and F. poae. Tested yeasts came from different culture collections, or were obtained from organic and conventional cereals. The greater number of yeast isolates from organic cereals showed antagonistic activity against fungi of the genus Fusarium compared to isolates from the conventional cultivation system. Cryptococcus carnescens (E22) isolated from organic wheat was the only isolate that limited the mycelial growth of all three tested fungi and was the best antagonist against F. poae. Selected yeasts showed various mechanisms of action against fungi, including competition for nutrients and space, production of volatile metabolites, reduction of spore germination, production of siderophores or production of extracellular lytic enzymes: chitinase and β-1,3-glucanase. Of all the investigated mechanisms of yeast antagonism against Fusarium, competition for nutrients and the ability to inhibit spore germination prevailed.

Early transcriptomic response of the mycoparasite Sphaerodes mycoparasitica to the mycotoxigenic Fusarium graminearum 3-ADON, the cause of Fusarium head blight

Mycoparasites are an assemblage of biotrophic and necrotrophic fungi that occur on plant pathogenic fungal hosts. Biotrophic mycoparasites are often overlooked in transcriptomic-based biocontrol studies. Sphaerodes mycoparasitica (S.m.) is a specific biotrophic mycoparasite of plant pathogenic Fusarium graminearum (F.g.), a devastating Fusarium head blight (FHB) disease in small-grain cereals. To understand the biotrophic mycoparasitism comprehensively, we performed Illumina RNA-Seq transcriptomic study on the fungus–fungus interaction in vitro. The aim is to identify the transcript-level mechanism related to the biotrophic S.m. mycoparasitism, particularly its ability to effectively control the F.g. 3-ADON chemotype. A shift in the transcriptomic profile of the mycoparasite was triggered in response to its interaction with F.g. during recognition (1.5 days) and colonization (3.5 days) steps. RNA-Seq analysis revealed ~ 30% of annotated transcripts with "function unknown". Further, 14 differentially expressed genes functionally linked to the biotrophic mycoparasitism were validated by quantitative real-time PCR (qPCR). The gene expression patterns of the filamentous haemagglutinin/adhesin/attachment factor as well as cell wall-degrading glucanases and chitinases were upregulated by host interaction. Besides, mycoparasitism-associated antioxidant resistance genes encoding ATP-binding cassette (ABC) transporter(s) and glutathione synthetase(s) were upregulated. However, the thioredoxin reductase was downregulated which infers that this antioxidant gene can be used as a resistance marker to assess S.m. antifungal and antimycotoxigenic activities. The interactive transcriptome of S. mycoparasitica provides new insights into specific mycoparasitism and will contribute to future research in controlling FHB.

Co-Occurrence of 35 Mycotoxins: A Seven-Year Survey of Corn Grain and Corn Silage in the United States

Mycotoxins contaminate crops worldwide and play a role in animal health and performance. Multiple mycotoxins may co-occur which may increase the impact on the animal. To assess the multiple mycotoxin profile of corn (Zea mays), we conducted a 7-year survey of new crop corn grain and silage in the United States. A total of 711 grain and 1117 silage samples were collected between 2013 and 2019 and analyzed for the simultaneous presence of 35 mycotoxins using ultra-performance liquid chromatography–tandem mass spectrometry. The measured mean number of mycotoxins per sample were 4.8 (grain) and 5.2 (silage), ranging from 0 to 13. Fusaric acid (FA) was most frequently detected in 78.1 and 93.8% of grains and silages, respectively, followed by deoxynivalenol (DON) in 75.7 and 88.2% of samples. Fumonisin B1 (FB1), fumonisin B2 and 15-acetyl-deoxynivalenol (15ADON) followed. The greatest (p < 0.05) co-occurrence was between FA and DON in 59.1% of grains and 82.7% of silages, followed by FA with FB1, DON with 15ADON, and FA with 15ADON. Although many samples had lower mycotoxin concentrations, 1.6% (grain) and 7.9% (silage) of tested samples had DON ≥ 5000 µg/kg. Fumonisins were detected ≥ 10,000 µg/kg in 9.6 and 3.9% of grain and silage samples, respectively. Concentrations in grain varied by year for eight mycotoxin groups (p < 0.05), while all 10 groups showed yearly variations in silage. Our survey suggest that multiple mycotoxins frequently co-occur in corn grain and silage in the United States, and some of the more prevalent mycotoxins are those that may not be routinely analyzed (i.e., FA and 15ADON). Assessment of multiple mycotoxins should be considered when developing management programs.

Multi-Mycotoxin Contamination of Maize Silages in Flanders, Belgium: Monitoring Mycotoxin Levels from Seed to Feed

Maize silage, which in Europe is the main feed for dairy cattle in winter, can be contaminated by mycotoxins. Mycotoxigenic Fusarium spp. originating from field infections may survive in badly sealed silages or re-infect at the cutting edge during feed-out. In this way, mycotoxins produced in the field may persist during the silage process. In addition, typical silage fungi such as Penicillium spp. and Aspergillus spp. survive in silage conditions and produce mycotoxins. In this research, 56 maize silages in Flanders were sampled over the course of three years (2016-2018). The concentration of 22 different mycotoxins was investigated using a multi-mycotoxin liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, and the presence of DNA of three Fusarium spp. (F. graminearum, F. culmorum and F. verticillioides) was analyzed in a selection of these samples using quantitative polymerase chain reaction (qPCR). Every maize silage contained at least two different mycotoxins. Nivalenol (NIV) and deoxynivalenol (DON) were the most prevalent (both in 97.7% of maize silages), followed by ENN B (88.7%). Concentrations often exceeded the EU recommendations for DON and zearalenone (ZEN), especially in 2017 (21.3% and 27.7% of the maize silages, respectively). No correlations were found between fungal DNA and mycotoxin concentrations. Furthermore, by ensiling maize with a known mycotoxin load in a net bag, the mycotoxin contamination could be monitored from seed to feed. Analysis of these net bag samples revealed that the average concentration of all detected mycotoxins decreased after fermentation. We hypothesize that mycotoxins are eluted, degraded, or adsorbed during fermentation, but certain badly preserved silages are prone to additional mycotoxin production during the stable phase due to oxygen ingression, leading to extremely high toxin levels.