Updated survey of Fusarium species and toxins in Finnish cereal grains

Diterpenes and triterpenes show potential as biocides against pathogenic fungi and oomycetes: a screening study

OBJECTIVES

The aim was to screen di- and triterpenes as potential biocides against fungal pathogens (Alternaria sp., Fusarium avenaceum, F. sambucinum, Botrytis cinerea, Botryotina fuckeliana, Mycocentrospora acerina, Cylindrocarpon sp.) and oomycetes (Phytophthora cactorum, P. fragariae). Results We measured the antifungal activity of terpenes by estimating the growth area, ergosterol content and level of lipid peroxidation. Fungi and oomycetes were grown on solid media in Petri dishes. As a positive control, we used a common synthetic fungicide, fosetyl-Al. Di- and triterpenes showed promising potential as biocides against most of the studied species. The responses of fungi and oomycetes were dependent on the specific type of terpenes and identity of the fungi. Compared to synthetic fungicide, terpenes were equally effective as antifungal agents and even more effective for some species, especially for oomycetes. The terpene mode of action includes inhibition of ergosterol synthesis and increased lipid peroxidation. Conclusions Di- and triterpenes, natural compounds that are very abundant in northern countries, are excellent candidates for biocides.

Intake and sources of dietary fibre and dietary fibre fractions in Finnish children

The current definition of dietary fibre was adopted by the Codex Alimentarius Commission in 2009, but implementation requires updating food composition databases with values based on appropriate analysis methods. Previous data on population intakes of dietary fibre fractions are sparse. We studied the intake and sources of total dietary fibre (TDF) and dietary fibre fractions insoluble dietary fibre (IDF), dietary fibre soluble in water but insoluble in 76 % aqueous ethanol (SDFP) and dietary fibre soluble in water and soluble in 76 % aqueous ethanol (SDFS) in Finnish children based on new CODEX-compliant values of the Finnish National Food Composition Database Fineli. Our sample included 5193 children at increased genetic risk of type 1 diabetes from the Type 1 Diabetes Prediction and Prevention birth cohort, born between 1996 and 2004. We assessed the intake and sources based on 3-day food records collected at the ages of 6 months, 1, 3 and 6 years. Both absolute and energy-adjusted intakes of TDF were associated with age, sex and breast-feeding status of the child. Children of older parents, parents with a higher level of education, non-smoking mothers and children with no older siblings had higher energy-adjusted TDF intake. IDF was the major dietary fibre fraction in non-breastfed children, followed by SDFP and SDFS. Cereal products, fruits and berries, potatoes and vegetables were major food sources of dietary fibre. Breast milk was a major source of dietary fibre in 6-month-olds due to its human milk oligosaccharide content and resulted in high SDFS intakes in breastfed children.

T-2 and HT-2 Toxins: Toxicity, Occurrence and Analysis: A Review

One of the major classes of mycotoxins posing serious hazards to humans and animals and potentially causing severe economic impact to the cereal industry are the trichothecenes, produced by many fungal genera. As such, indicative limits for the sum of T-2 and HT-2 were introduced in the European Union in 2013 and discussions are ongoing as to the establishment of maximum levels. This review provides a concise assessment of the existing understanding concerning the toxicological effects of T-2 and HT-2 in humans and animals, their biosynthetic pathways, occurrence, impact of climate change on their production and an evaluation of the analytical methods applied to their detection. This study highlights that the ecology of F. sporotrichioides and F. langsethiae as well as the influence of interacting environmental factors on their growth and activation of biosynthetic genes are still not fully understood. Predictive models of Fusarium growth and subsequent mycotoxin production would be beneficial in predicting the risk of contamination and thus aid early mitigation. With the likelihood of regulatory maximum limits being introduced, increased surveillance using rapid, on-site tests in addition to confirmatory methods will be required. allowing the industry to be proactive rather than reactive.

Development of a real-time PCR and multiplex PCR assay for the detection and identification of mycotoxigenic fungi in stored maize grains

This study aimed to identify important mycotoxigenic fungi and accurate detection of mycotoxin in stored maize grains using molecular methods. The current study also optimised the real-time PCR (RT-PCR) assay. The melting curve was established to identify isolated fungal species of Aspergillus (4), Fusarium (3), Penicillium (3), and Alternaria (one). A multiplex polymerase chain reaction (mPCR) technique was developed for the detection and characterisation of mycotoxin producing fungi, mycotoxin metabolic pathway genes, and the determination of eleven mycotoxins in stored maize grains using high-performance liquid chromatography (HPLC). The mPCR results indicated positive signals for potentially mycotoxigenic fungal species tested of Aspergillus, Fusarium, Penicillium, and Alternaria. A protocol for multiplex reverse transcription-polymerase chain reaction (mRT-PCR) was tested to distinguish between free and contaminated, stored maize with aflatoxin B1 (AFB1). The expression pattern of four aflatoxin biosynthetic pathway genes, AFB1 (aflQ, aflP, aflO, and aflD), was a good marker for contaminated, stored maize grains. HPLC analysis showed that maize grain samples were contaminated with mycotoxins, and the concentration was above the detection level. The results indicate that the polyphasic approach might provide a sensitive, rapid, and accurate method for detecting and identifying mycotoxigenic fungal species and mycotoxins in stored maize grains.

Population structure and genetic diversity of Fusarium graminearum from southwestern Russia and the Russian Far East as compared with northern Europe and North America

Genetic variation at variable number tandem repeat (VNTR) markers was used to assess population structure and diversity among 296 Fusarium graminearum isolates from northern Europe (Finland, northwestern Russia, and Norway), southern Europe (southwestern and western Russia), and Asia (Siberia and the Russian Far East). We identified at least two highly differentiated and geographically structured genetic populations (E1 and E2) in Eurasia (Φ_PT = 0.35). Isolates from northern Europe were almost exclusively from the E1 population (95.6%) and had the 3ADON (3-acetyldeoxynivalenol) trichothecene genotype (97.3%). In contrast, all isolates from southern Europe were from the E2 population and 94.4% had the 15ADON (15-acetyldeoxynivalenol) genotype. The E2 population also predominated in the Asian sampling locations (92.7%) where 3ADON and 15ADON genotypes occurred at nearly equal frequencies. Southern European isolates were more closely related to those from Asia (Φ_PT = 0.06) than to geographically closer populations from northern Europe (Φ_PT ≥ 0.31). Northern European populations also harbored substantially less genetic diversity (Ne ≤ 2.1) than populations in southern Europe or Asia (Ne ≥ 3.4), indicative of a selective sweep or recent introduction and subsequent range expansion in northern Europe. Bayesian analyses incorporating previously described genetic populations from North America (NA1 and NA2) surprisingly identified NA2 and E2 as a single genetic population, consistent with hypotheses of a recent Eurasian origin for NA2. Additionally, more than 10% of the isolates from Asia and southern Europe were assigned to the NA1 population, indicating recent introductions of NA1 into parts of Eurasia. Collectively, these results demonstrate that there are at least three genetic populations of F. graminearum in the Northern Hemisphere and indicate that population-level diversity in Eurasia and North America has been shaped by recent transcontinental introductions.

Impact of Enniatin and Deoxynivalenol Co-Occurrence on Plant, Microbial, Insect, Animal and Human Systems: Current Knowledge and Future Perspectives

Fusarium mycotoxins commonly contaminate agricultural products resulting in a serious threat to both animal and human health. The co-occurrence of different mycotoxins in the same cereal field is very common, so the risks as well as the functional and ecological effects of mycotoxins cannot always be predicted by focusing only on the effect of the single contaminants. Enniatins (ENNs) are among the most frequently detected emerging mycotoxins, while deoxynivalenol (DON) is probably the most common contaminant of cereal grains worldwide. The purpose of this review is to provide an overview of the simultaneous exposure to these mycotoxins, with emphasis on the combined effects in multiple organisms. Our literature analysis shows that just a few studies on ENN-DON toxicity are available, suggesting the complexity of mycotoxin interactions, which include synergistic, antagonistic, and additive effects. Both ENNs and DON modulate drug efflux transporters, therefore this specific ability deserves to be explored to better understand their complex biological role. Additionally, future studies should investigate the interaction mechanisms of mycotoxin co-occurrence on different model organisms, using concentrations closer to real exposures.

Image-based time series analysis to establish differential disease progression for two Fusarium head blight pathogens in oat spikelets with variable resistance

Oat-based value-added products have increased their value as healthy foodstuff. Fusarium head blight (FHB) infections and the mycotoxins accumulated to the oat seeds, however, pose a challenge to oat production. The FHB infections are predicted to become more prevalent in the future changing climates and under more limited use of fungicides. Both these factors increase the pressure for breeding new resistant cultivars. Until now, however, genetic links in oats against FHB infection have been difficult to identify. Therefore, there is a great need for more effective breeding efforts, including improved phenotyping methods allowing time series analysis and the identification of molecular markers during disease progression. To these ends, dissected spikelets of several oat genotypes with different resistance profiles were studied by image-based methods during disease progression by Fusarium culmorum or F. langsethiae species. The chlorophyll fluorescence of each pixel in the spikelets was recorded after inoculation by the two Fusarium spp., and the progression of the infections was analyzed by calculating the mean maximum quantum yield of PSII (F_v/F_m) values for each spikelet. The recorded values were (i) the change in the photosynthetically active area of the spikelet as percentage of its initial size, and (ii) the mean of F_v/F_m values of all fluorescent pixels per spikelet post inoculation, both indicative of the progression of the FHB disease. The disease progression was successfully monitored, and different stages of the infection could be defined along the time series. The data also confirmed the differential rate of disease progression by the two FHB causal agents. In addition, oat varieties with variable responses to the infections were indicated.

Biocontrol Effect of Clonostachys rosea on Fusarium graminearum Infection and Mycotoxin Detoxification in Oat (Avena sativa)

Oat (Avena sativa) is susceptible to Fusarium head blight (FHB). The quality of oat grain is threatened by the accumulation of mycotoxins, particularly the trichothecene deoxynivalenol (DON), which also acts as a virulence factor for the main pathogen Fusarium graminearum. The plant can defend itself, e.g., by DON detoxification by UGT-glycosyltransferases (UTGs) and accumulation of PR-proteins, even though these mechanisms do not deliver effective levels of resistance. We studied the ability of the fungal biocontrol agent (BCA) Clonostachys rosea to reduce FHB and mycotoxin accumulation. Greenhouse trials showed that C. rosea-inoculation of oat spikelets at anthesis 3 days prior to F. graminearum inoculation reduced both the amount of Fusarium DNA (79%) and DON level (80%) in mature oat kernels substantially. DON applied to C. rosea-treated spikelets resulted in higher conversion of DON to DON-3-Glc than in mock treated plants. Moreover, there was a significant enhancement of expression of two oat UGT-glycosyltransferase genes in C. rosea-treated oat. In addition, C. rosea treatment activated expression of genes encoding four PR-proteins and a WRKY23-like transcription factor, suggesting that C. rosea may induce resistance in oat. Thus, C. rosea IK726 has strong potential to be used as a BCA against FHB in oat as it inhibits F. graminearum infection effectively, whilst detoxifying DON mycotoxin rapidly.

Epiphytic and Endophytic Fungi Colonizing Seeds of Two Poaceae Weed Species and Fusarium spp. Seed Degradation Potential In Vitro

Fungi colonizing the surface and endosphere of two widespread Poaceae weed species, Avena fatua and Echinochloa crus-galli, were isolated to compare the taxonomic composition between the plant species, location, and year of the seed collection. The seed-degrading potential of Fusarium isolated from the seeds was tested by inoculating seeds of E. crus-galli with spore suspension. Molecular identification of epiphytic and endophytic fungal genera was performed by sequencing the ITS region of rDNA. Endophytes comprised of significantly lower fungal richness compared to epiphytes. A significant taxonomic overlap was observed between the endosphere and seed surface. The most abundant genera were Alternaria, Fusarium, Cladosporium, and Sarocladium. Analysis of similarities and hierarchical clustering showed that microbial communities were more dissimilar between the two plant species than between the years. Fusarium isolates with a high potential to infect and degrade E. crus-galli seeds in laboratory conditions belong to F. sporotrichioides and F. culmorum.

Interaction of methyl-jasmonate and Fusarium poae in bread wheat

Fusarium Head Blight (FHB) is a devastating disease that affects the grain yield and quality of essential crops such as wheat. In the last years, some Fusarium species have acquired particular importance as Fusarium poae. However, studies to evaluate F. poae-wheat interaction are still scarce. The interaction between F. poae and two bread wheat cultivars with different resistance levels against FHB was evaluated. Moreover, the application of methyl-jasmonate (MeJA) was evaluated as a possible tool to reduce the fungal presence. Our results showed that the MeJA treatment is isolate-dependent, reducing F. poae fungal growth. A decrease in fungal biomass was observed in the susceptible cultivar after MeJA application; however, no differences between inoculated and inoculated-MeJA treatments were observed in the resistant cultivar. Finally, the F. poae inoculation induces the expression of PR1-1 and PDF 1.2, being early in the resistant cultivar compared to the susceptible ones. The application of MeJA combined with the F. poae inoculation increased PR1-1 and PDF1.2 expressions in resistant cultivars. To our knowledge, this is the first study that evaluates the interaction between F. poae and wheat and the MeJA treatment as a possible management strategy against this important pathogen.

Temporal and spatial dynamics of Fusarium spp. and mycotoxins in Swedish cereals during 16 years

We analysed the dynamics of Fusarium spp. and mycotoxin contamination in Swedish cereals during 2004–2018. More than 1400 cereal samples from field trials were included, collected in a monitoring programme run by the Swedish Board of Agriculture. Five Fusarium mycotoxins were quantified with LC-MS/MS and fungal DNA from four species was quantified using quantitative real-time PCR. Correlation analyses revealed that deoxynivalenol (DON) and zearalenone (ZEN) were mainly associated with Fusarium graminearum, but stronger correlations with F. culmorum was seen some years. Nivalenol (NIV) was associated with F. poae and the HT-2 and T-2 toxins with F. langsethiae. Clear differences in mycotoxin contamination between different cereal crops and geographical regions were identified. The highest levels of DON and ZEN were found in spring wheat in Western Sweden. For NIV, HT-2 and T-2 toxins, the levels were highest in spring oats and spring barley. Regional differences were not detected for NIV, while HT-2 and T-2 toxins were associated with the northernmost region. We found that delayed harvest was strongly associated with increased levels of DON and ZEN in several crops. However, harvest date did not influence the levels of NIV or HT-2 and T-2 toxins. Our results suggest similar distribution patterns of DON and ZEN, in contrast to NIV and HT-2 and T-2 toxins, probably mirroring the differences in the ecology of the toxin-producing Fusarium species. Timely harvest is important to reduce the risk of DON and ZEN contamination, especially for fields with other risk factors.

Searching for the Fusarium spp. Which Are Responsible for Trichothecene Contamination in Oats Using Metataxonomy to Compare the Distribution of Toxigenic Species in Fields from Spain and the UK

The contamination of oats with Fusarium toxins poses a high risk for food safety. Among them, trichothecenes are the most frequently reported in European oats, especially in northern countries. The environmental conditions related to the climate change scenario might favour a distribution shift in Fusarium species and the presence of these toxins in Southern European countries. In this paper, we present an ambitious work to determine the species responsible for trichothecene contamination in Spanish oats and to compare the results in the United Kingdom (UK) using a metataxonomic approach applied to both oat grains and soil samples collected from both countries. Regarding T-2 and HT-2 toxin producers, F. langsethiae was detected in 38% and 25% of the oat samples from the UK and Spain, respectively, and to the best of our knowledge, this is the first report of the detection of this fungus in oats from Spain. The relevant type B trichothecene producer, F. poae, was the most frequently detected Fusarium species in oats from both origins. Other important trichothecene producers, such as the Fusarium tricinctum species complex or Fusarium cerealis, were also frequently detected in oat fields. Many Fusarium toxins, including T-2 and HT-2 toxins, deoxynivalenol, or nivalenol, were detected in oat samples. The results obtained in this work revealed a clear change in the distribution of trichothecene producers and the necessity to establish the potential of these species to colonize oats and their ability to produce mycotoxins.

Identification and Functional Characterisation of Two Oat UDP-Glucosyltransferases Involved in Deoxynivalenol Detoxification

Oat is susceptible to several Fusarium species that cause contamination with different trichothecene mycotoxins. The molecular mechanisms behind Fusarium resistance in oat have yet to be elucidated. In the present work, we identified and characterised two oat UDP-glucosyltransferases orthologous to barley HvUGT13248. Overexpression of the latter in wheat had been shown previously to increase resistance to deoxynivalenol (DON) and nivalenol (NIV) and to decrease disease the severity of both Fusarium head blight and Fusarium crown rot. Both oat genes are highly inducible by the application of DON and during infection with Fusarium graminearum. Heterologous expression of these genes in a toxin-sensitive strain of Saccharomyces cerevisiae conferred high levels of resistance to DON, NIV and HT-2 toxins, but not C4-acetylated trichothecenes (T-2, diacetoxyscirpenol). Recombinant enzymes AsUGT1 and AsUGT2 expressed in Escherichia coli rapidly lost activity upon purification, but the treatment of whole cells with the toxin clearly demonstrated the ability to convert DON into DON-3-O-glucoside. The two UGTs could therefore play an important role in counteracting the Fusarium virulence factor DON in oat.

Reduction of deoxynivalenol, T-2 and HT-2 toxins and associated Fusarium species during commercial and laboratory de-hulling of milling oats

Oats (Avena sativa L.) are well known for their nutritional properties but are susceptible to the growth of different Fusarium fungi resulting in mycotoxin contamination of harvested oats. In this study, oat samples from harvest years 2011 to 2017 were preselected for their suitability as milling oats for food purposes with DON contents below 1750 µg/kg. The reduction of DON, T-2 and HT-2 toxins during the commercial de-hulling process was analysed. While the average reduction for the sum of T-2 and HT-2 toxins in large oat kernels was 85%, the reduction for thin kernels was 66%. The reduction for DON was about 60% and did not differ for the two kernel fractions. In laboratory de-hulling experiments, milling oat samples and de-hulled oat kernels with known DON, T-2 and HT-2 toxin content were correlated with the associated DNA amount of Fusarium graminearum, Fusarium culmorum and Fusarium langsethiae. The reduction of the Fusarium DNA amount after de-hulling was comparable to the reduction of the associated mycotoxins. Notably, the correlation between F. langsethiae DNA amounts and the sum of T-2 and HT-2 toxin contents was R² = 0.69 in milling oats and it rose to R² = 0.85 in de-hulled oat kernels. In laboratory tests, at least one third of the initial levels of DON and the sum of T-2 and HT-2 toxins could be removed by polishing off the first parts of the outer layers; two thirds remained in the polished oat kernels. These observations indicate that de-hulling alone may not be completely sufficient to remove mycotoxin contamination in oats. These findings are of high importance in the discussion of determining legal maximum levels for DON or the sum of T-2 and HT-2 toxins in intermediate and final products.

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.

Cytochrome P450 isoforms contribution, plasma protein binding, toxicokinetics of enniatin A in rats and in vivo clearance prediction in humans

Emerging mycotoxins, such as enniatin A (ENNA), are becoming a worldwide concern owing to their presence in different types of food and feed. However, comprehensive toxicokinetic data that links intake, exposure and toxicological effects of ENNA has not been elucidated yet. Therefore, the present study investigated the in vitro (rat and human) and in vivo (rat) toxicokinetic properties of ENNA. Towards this, an easily applicable and sensitive bioanalytical method was developed and validated for the estimation of ENNA in rat plasma. ENNA exhibited high plasma protein binding (99%), high hepatic clearance and mainly underwent metabolism via CYP3A4 (74%). The in-house predicted hepatic clearance (54 mL/min/kg) and observed in vivo rat clearance (55 mL/min/kg) were comparable. The predicted in vivo human hepatic clearance was 18 mL/min/kg. ENNA underwent slow absorption (T_max = 4 h) and rapid elimination following oral administration to rats. The absolute oral bioavailability was 47%. The toxicokinetic findings for ENNA from this study will help in designing and interpreting toxicological studies in rats. Besides, these findings could be used in physiologically based toxicokinetic (PBTK) model development for exposure predictions and risk assessment for ENNA in humans.

Host Genotype and Weather Effects on Fusarium Head Blight Severity and Mycotoxin Load in Spring Barley

Epidemiology of Fusarium Head Blight (FHB) of spring barley is relatively little understood. In a five-year study, we assessed quantitative resistance to FHB in an assortment of 17 spring barley genotypes in the field in southern Germany. To this end, we used soil and spray inoculation of plants with F. culmorum and F. avenaceum. This increased disease pressure and provoked genotypic differentiation. To normalize effects of variable weather conditions across consecutive seasons, we used a disease ranking of the genotypes based on quantification of fungal DNA contents and multiple Fusarium toxins in harvested grain. Together, this allowed for assessment of stable quantitative FHB resistance of barley in several genotypes. Fungal DNA contents were positively associated with species-specific Fusarium toxins in single years and over several years in plots with soil inoculation. In those plots, plant height limited FHB; however, this was not observed after spray inoculation. A multiple linear regression model of recorded weather parameter and fungal DNA contents over five years identified time periods during the reproductive phase of barley, in which weather strongly influenced fungal colonization measured in mature barley grain. Environmental conditions before heading and late after anthesis showed strongest associations with F. culmorum DNA in all genotypes, whereas for F. avenaceum, this was less consistent where we observed weather-dependent associations, depending on the genotype. Based on this study, we discuss aspects of practical resistance breeding in barley relevant to improve quantitative resistance to FHB and associated mycotoxin contaminations.

Taqman qPCR Quantification and Fusarium Community Analysis to Evaluate Toxigenic Fungi in Cereals

Fusarium head blight (FHB) is an economically important plant disease. Some Fusarium species produce mycotoxins that cause food safety concerns for both humans and animals. One especially important mycotoxin-producing fungus causing FHB is Fusarium graminearum. However, Fusarium species form a disease complex where different Fusarium species co-occur in the infected cereals. Effective management strategies for FHB are needed. Development of the management tools requires information about the diversity and abundance of the whole Fusarium community. Molecular quantification assays for detecting individual Fusarium species and subgroups exist, but a method for the detection and quantification of the whole Fusarium group is still lacking. In this study, a new TaqMan-based qPCR method (FusE) targeting the Fusarium-specific elongation factor region (EF1α) was developed for the detection and quantification of Fusarium spp. The FusE method was proven as a sensitive method with a detection limit of 1 pg of Fusarium DNA. Fusarium abundance results from oat samples correlated significantly with deoxynivalenol (DON) toxin content. In addition, the whole Fusarium community in Finnish oat samples was characterized with a new metabarcoding method. A shift from F. culmorum to F. graminearum in FHB-infected oats has been detected in Europe, and the results of this study confirm that. These new molecular methods can be applied in the assessment of the Fusarium community and mycotoxin risk in cereals. Knowledge gained from the Fusarium community analyses can be applied in developing and selecting effective management strategies for FHB.

Survey of Freshly Harvested Oat Grains from Southern Brazil Reveals High Incidence of Type B Trichothecenes and Associated Fusarium Species

The current study investigated the fungal diversity in freshly harvested oat samples from the two largest production regions in Brazil, Paraná (PR) and Rio Grande do Sul (RS), focusing primarily on the Fusarium genus and the presence of type B trichothecenes. The majority of the isolates belonged to the Fusarium sambucinum species complex, and were identified as F. graminearum sensu stricto (s.s.), F. meridionale, and F. poae. In the RS region, F. poae was the most frequent fungus, while F. graminearum s.s. was the most frequent in the PR region. The F. graminearum s.s. isolates were 15-ADON genotype, while F. meridionale and F. poae were NIV genotype. Mycotoxin analysis revealed that 92% and 100% of the samples from PR and RS were contaminated with type B trichothecenes, respectively. Oat grains from PR were predominantly contaminated with DON, whereas NIV was predominant in oats from RS. Twenty-four percent of the samples were contaminated with DON at levels higher than Brazilian regulations. Co-contamination of DON, its derivatives, and NIV was observed in 84% and 57.7% of the samples from PR and RS, respectively. The results provide new information on Fusarium contamination in Brazilian oats, highlighting the importance of further studies on mycotoxins.

Effects of Fusarium metabolites beauvericin and enniatins alone or in mixture with deoxynivalenol on weaning piglets

The impact of the Fusarium-derived metabolites beauvericin, enniatin B and B1 (EB) alone or in combination with deoxynivalenol (DON) was investigated in 28-29 days old weaning piglets over a time period of 14 days. The co-application of EB and DON (EB + DON) led to a significant decrease in the weight gain of the animals. Liver enzyme activities in plasma were significantly decreased at day 14 in piglets receiving the EB + DON-containing diet compared to piglets receiving the control diet. All mycotoxin-contaminated diets led to moderate to severe histological lesions in the jejunum, the liver and lymph nodes. Shotgun metagenomics revealed a significant effect of EB-application on the gut microbiota. Our results provide novel insights into the harmful impact of emerging mycotoxins alone or with DON on the performance, gut health and immunological parameters in pigs.

Agronomic Factors Influencing the Scale of Fusarium Mycotoxin Contamination of Oats

Seven agronomic factors (crop season, farming system, harvest date, moisture, county, oat variety, and previous crop) were recorded for 202 oat crops grown across Ireland, and samples were analysed by LC-MS/MS for four major Fusarium mycotoxins: deoxynivalenol (DON), zearalenone (ZEN), T-2 toxin and HT-2 toxin. Type A trichothecenes were present in 62% of crops, with 7.4% exceeding European regulatory limits. DON (6.4%) and ZEN (9.9%) occurrences were relatively infrequent, though one and three samples were measured over their set limits, respectively. Overall, the type of farming system and the previous crop were the main factors identified as significantly influencing mycotoxin prevalence or concentration. Particularly, the adherence to an organic farming system and growing oats after a previous crop of grass were found to decrease contamination by type A trichothecenes. These are important findings and may provide valuable insights for many other types of cereal crops as Europe moves towards a much greater organic-based food system.

Modelling the Effects of Weather Conditions on Cereal Grain Contamination with Deoxynivalenol in the Baltic Sea Region

Fusarium head blight (FHB) is one of the most serious diseases of small-grain cereals worldwide, resulting in yield reduction and an accumulation of the mycotoxin deoxynivalenol (DON) in grain. Weather conditions are known to have a significant effect on the ability of fusaria to infect cereals and produce toxins. In the past 10 years, severe outbreaks of FHB, and grain DON contamination exceeding the EU health safety limits, have occurred in countries in the Baltic Sea region. In this study, extensive data from field trials in Sweden, Poland and Lithuania were analysed to identify the most crucial weather variables for the ability of Fusarium to produce DON. Models were developed for the prediction of DON contamination levels in harvested grain exceeding 200 µg kg⁻¹ for oats, spring barley and spring wheat in Sweden and winter wheat in Poland, and 1250 µg kg⁻¹ for spring wheat in Lithuania. These models were able to predict high DON levels with an accuracy of 70–81%. Relative humidity (RH) and precipitation (PREC) were identified as the weather factors with the greatest influence on DON accumulation in grain, with high RH and PREC around flowering and later in grain development and ripening correlated with high DON levels. High temperatures during grain development and senescence reduced the risk of DON accumulation. The performance of the models, based only on weather variables, was relatively accurate. In future studies, it might be of interest to determine whether inclusion of variables such as pre-crop, agronomic factors and crop resistance to FHB could further improve the performance of the models.

Survey of mycotoxins in milling oats dedicated for food purposes between 2013 and 2019 by LC-MS/MS

Although the common oat (Avena sativa L.) is well known for its nutritional benefits, it carries the risk of contamination with mycotoxins due to its susceptibility to the growth of various fungi. The procurement of milling oats for food could become more difficult in the coming harvest years due to limited availability, specific quality requirements and the avoidance of mycotoxin contamination. In light of ongoing discussions in the European Commission on regulatory limits for certain mycotoxins including their modified forms, the purpose of this study was to improve the database on their occurrence in milling oats. In particular, we provide data on the predominantly occurring trichothecenes such as deoxynivalenol and its acetylated and modified derivatives (e.g. 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol and deoxynivalenol-3-glucoside) as well as on T-2 and HT-2 toxins. Additionally, the following mycotoxins were analysed: zearalenone, nivalenol, diacetoxyscirpenol, fusarenon-X, ochratoxin A, sterigmatocystin and aflatoxins B₁, B₂, G₁ and G₂. Oat samples, (n = 281) pre-selected for their physical properties and DON-content to be less than 1750 µg/kg from 11 European provenances, were analysed for 16 different mycotoxins by LC-MS/MS. Samples were collected from the years of harvest 2013 to 2019. High incidence rates above the limit of quantification of either 5 µg/kg for T-2 and HT-2 toxins or 10 µg/kg for deoxynivalenol were found (98.1, 94.7 and 91.4%, respectively). The mean concentration of the sum of T-2 and HT-2 toxins was 149 µg/kg. The highest level was found in an Irish sample containing 1290 µg/kg for the sum of T-2 and HT-2 toxins. The mean deoxynivalenol concentration was 289 µg/kg, while the highest level was 1414 µg/kg in a Swedish sample. Besides nivalenol other mycotoxins were only present in trace concentrations or not detected.

Potential Health Risk Associated with Mycotoxins in Oat Grains Consumed in Spain

Spain is a relevant producer of oats (Avena sativa), but to date there has been no study on the occurrence/co-occurrence of mycotoxins in oats marketed in Spain. The present study is addressed to overcome this lack of knowledge. One hundred oat kernel samples were acquired across different Spanish geographic regions during the years 2015-2019 and analyzed for mycotoxin content using an ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) method and matrix-matched calibration. The focus was on the regulated mycotoxins although other relevant mycotoxins were considered. The percentage of incidence (levels ≥ limit of detection), mean and range (ng/g) of mycotoxins were as follows: zearalenone (66%, mean 39.1, range 28.1-153), HT-2 toxin (47%, mean 37.1, range 4.98-439), deoxynivalenol, (34%, mean 81.4, range 19.1-736), fumonisin B1 (29%, mean 157.5, range 63.2-217.4), and T-2 toxin, (24%, mean 49.9, range 12.3-321). Fumonisin B2, 3-acetyldeoxynivalenol, aflatoxins B1, B2, and G2, and ochratoxin A were also detected at low levels, but aflatoxin G1 was not. The maximum limits established by the European Commission for unprocessed oats were not exceeded, except for zearalenone (in one sample), and the sum of aflatoxins (in two samples). Mycotoxin co-occurrence at quantifiable levels in the same sample (two to five combinations) was found in 31% of samples. The most common mixtures were those of HT-2 + T-2 toxins alone or together with deoxynivalenol and/or zearalenone.

Mycotoxins Biocontrol Methods for Healthier Crops and Stored Products

Contamination of crops with phytopathogenic genera such as Fusarium, Aspergillus, Alternaria, and Penicillium usually results in mycotoxins in the stored crops or the final products (bread, beer, etc.). To reduce the damage and suppress the fungal growth, it is common to add antifungal substances during growth in the field or storage. Many of these antifungal substances are also harmful to human health and the reduction of their concentration would be of immense importance to food safety. Many eminent researchers are seeking a way to reduce the use of synthetic antifungal compounds and to implement more eco-friendly and healthier bioweapons against fungal proliferation and mycotoxin synthesis. This paper aims to address the recent advances in the effectiveness of biological antifungal compounds application against the aforementioned fungal genera and their species to enhance the protection of ecological and environmental systems involved in crop growing (water, soil, air) and to reduce fungicide contamination of food derived from these commodities.

Development and Validation of a UHPLC-MS/MS Method for the Analysis of Fusarium Mycotoxins in Onion

Fusarium basal rot (FBR) of onion is a serious disease problem worldwide. The Fusarium species causing FBR can also produce mycotoxins that are potentially harmful to humans and animals. In this study, a multiple reaction monitoring technique with ultra-high-performance liquid chromatography–tandem mass spectrometry (MRM UHPLC-MS/MS) was developed and validated for onion matrix to study Fusarium mycotoxins in the harvested onions. This study was focused on fumonisins B1, B2, and B3 (FB1, FB2, and FB3), beauvericin (BEA), and moniliformin (MON), which are the main mycotoxins produced by Fusarium oxysporum and Fusarium proliferatum. In the in-house validated protocol, the onion samples were extracted with methanol:water (3:1) using magnetic stirring for 15 min. FBs and BEA were determined directly from the filtered extracts, whereas MON required sample concentration prior to analysis. No cleanup of extracts was needed prior to analysis. The target mycotoxins were separated on an Acquity UPLC system BEH C18 column with gradient elution. Mycotoxins were identified and quantified using 13C-FB1 as internal standard. Minor matrix effect was compensated using multi-point matrix-matched calibration curves with uninfected onion sample. For the mycotoxins studied, a good linearity was obtained (R2 ≥ 0.99) and the recoveries were in the range of 67–122%, with the highest standard deviation for MON, 22%. The limits of quantification were from 2.5 to 10 ng g−1 in onion matrix. The method was successfully employed for the analysis of mycotoxins in harvested onions showing FBR symptoms and found to be infected with F. oxysporum and F. proliferatum.

Natural Co-Occurrence of Multiple Mycotoxins in Unprocessed Oats Grown in Ireland with Various Production Systems

The natural co-occurrence of 42 mycotoxins was investigated in unprocessed oat grains grown in Ireland. The sample set included a total of 208 oat crops harvested during 2015–2016 and produced using conventional, organic, or gluten free farming systems. A range of different toxins was identified, including the major type A (neosolaniol, HT-2 and T-2 toxins, T-2 triol, and T-2-glucoside, co-occurring in 21 samples) and B trichothecenes (deoxynivalenol, nivalenol, and deoxynivalenol-3-glucoside), enniatins (B1, B, and A1, co-occurring in 12 samples), as well as beauvericin, alternariol, mycophenolic acid, and sterigmatocystin. The influences of sowing season, year, and production system were investigated, eventually indicating that the latter factor may have a higher impact than others on the production of certain mycotoxins in oats. The most frequently quantified compounds were HT-2 (51%) and T-2 (41%) toxins, with gluten free oats containing significantly lower concentrations of HT-2 compared to conventionally produced oats. Although the prevalence and concentrations of mycotoxin found in oat samples in this study should be substantially reduced by processing. However, as mycotoxin occurrence is clearly influenced by multiple factors, controlled field trials should be carried out to define optimal agronomic practices and mitigate mycotoxin production. Furthermore, this work highlights the need for regularly testing cereal-based foods with multi-residue analytical methods with wider specificities than the traditionally screened and regulated toxins, to generate knowledge on the occurrence of several mycotoxins that are, to date, rarely investigated.

Trichothecenes in Food and Feed, Relevance to Human and Animal Health and Methods of Detection: A Systematic Review

Trichothecene mycotoxins are sesquiterpenoid compounds primarily produced by fungi in taxonomical genera such as Fusarium, Myrothecium, Stachybotrys, Trichothecium, and others, under specific climatic conditions on a worldwide basis. Fusarium mold is a major plant pathogen and produces a number of trichothecene mycotoxins including deoxynivalenol (or vomitoxin), nivalenol, diacetoxyscirpenol, and T-2 toxin, HT-2 toxin. Monogastrics are sensitive to vomitoxin, while poultry and ruminants appear to be less sensitive to some trichothecenes through microbial metabolism of trichothecenes in the gastrointestinal tract. Trichothecene mycotoxins occur worldwide however both total concentrations and the particular mix of toxins present vary with environmental conditions. Proper agricultural practices such as avoiding late harvests, removing overwintered stubble from fields, and avoiding a corn/wheat rotation that favors Fusarium growth in residue can reduce trichothecene contamination of grains. Due to the vague nature of toxic effects attributed to low concentrations of trichothecenes, a solid link between low level exposure and a specific trichothecene is difficult to establish. Multiple factors, such as nutrition, management, and environmental conditions impact animal health and need to be evaluated with the knowledge of the mycotoxin and concentrations known to cause adverse health effects. Future research evaluating the impact of low-level exposure on livestock may clarify the potential impact on immunity. Trichothecenes are rapidly excreted from animals, and residues in edible tissues, milk, or eggs are likely negligible. In chronic exposures to trichothecenes, once the contaminated feed is removed and exposure stopped, animals generally have an excellent prognosis for recovery. This review shows the occurrence of trichothecenes in food and feed in 2011-2020 and their toxic effects and provides a summary of the discussions on the potential public health concerns specifically related to trichothecenes residues in foods associated with the exposure of farm animals to mycotoxin-contaminated feeds and impact to human health. Moreover, the article discusses the methods of their detection.

Tillage System and Crop Sequence Affect Soil Disease Suppressiveness and Carbon Status in Boreal Climate

The soil-borne plant pathogens cause serious yield losses and are difficult to control. In suppressive soils, disease incidence remains low regardless of the presence of the pathogen, the host plant, and favorable environmental conditions. The potential to improve natural soil disease suppressiveness through agricultural management practices would enable sustainable and resilient crop production systems. Our aim was to study the impact of autumn tillage methods and crop sequence on the soil carbon status, fungistasis and yield in boreal climate. The disease suppression was improved by the long-term reduced and no tillage management practices with and without crop rotation. Compared to the conventional plowing, the non-inversion tillage systems were shown to change the vertical distribution of soil carbon fractions and the amount of microbial biomass by concentrating them on the soil surface. Crop sequence and the choice of tillage method had a combined effect on soil organic carbon (SOC) sequestration. The improved general disease suppression had a positive correlation with the labile carbon status and microbial biomass. From the most common Fusarium species, the predominantly saprophytic F. avenaceum was more abundant under non-inversion practice, whereas the opposite was true for the pathogenic ones. Our findings furthermore demonstrated the correlation of the soil fungistasis laboratory assay results and the prevalence of the pathogenic test fungus Fusarium culmorum on the crop cereals in the field. Our results indicate that optimized management strategies have potential to improve microbial related soil fungistasis in boreal climate.

Fusarium Mycotoxins in Two Hulless Oat and Barley Cultivars Used for Food Purposes

Hulless oats and hulless barley are highly valued for their excellent nutritional attributes and are increasingly being promoted in human nutrition. However, special attention should be paid to the risk of their contamination by Fusarium mycotoxins, as the rate of mycotoxin reduction during processing could be much lower than that for hulled cereals. In the present study, mycotoxin contamination of two cultivars, each of hulless oats and barley suitable for food purposes were studied in a 3-year field trial established in two contrasting environments. The contents of the mycotoxins regulated by law (deoxynivalenol and zearalenone) were low, and the present legal limits for their maximum content in unprocessed cereals were far from being exceeded. The mycotoxins most frequently occurring in hulless barley were enniatins (enniatin B, enniatin B₁ and enniatin A₁), beauvericin and nivalenol; hulless oats most frequently contained the HT-2 and T-2 toxins, beauvericin and enniatin B. The contents of enniatins and nivalenol were higher in barley than in oats. Close, positive relationships between the contents of the individual enniatins and between enniatins, beauvericin and nivalenol were observed, which implies that co-exposure could enhance the toxic potential of these mycotoxins through synergistic effects. The results highlight the need to pay more attention to the occurrence of enniatins, beauvericine and nivalenol in hulless oats and barley used for food purposes.

Removal of Small Kernels Reduces the Content of Fusarium Mycotoxins in Oat Grain

Cereal grain contaminated by Fusarium mycotoxins is undesirable in food and feed because of the harmful health effects of the mycotoxins in humans and animals. Reduction of mycotoxin content in grain by cleaning and size sorting has mainly been studied in wheat. We investigated whether the removal of small kernels by size sorting could be a method to reduce the content of mycotoxins in oat grain. Samples from 24 Norwegian mycotoxin-contaminated grain lots (14 from 2015 and 10 from 2018) were sorted by a laboratory sieve (sieve size 2.2 mm) into large and small kernel fractions and, in addition to unsorted grain samples, analyzed with LC-MS-MS for quantification of 10 mycotoxins. By removing the small kernel fraction (on average 15% and 21% of the weight of the samples from the two years, respectively), the mean concentrations of HT-2+T-2 toxins were reduced by 56% (from 745 to 328 µg/kg) in the 2015 samples and by 32% (from 178 to 121 µg/kg) in the 2018 samples. Deoxynivalenol (DON) was reduced by 24% (from 191 to 145 µg/kg) in the 2018 samples, and enniatin B (EnnB) by 44% (from 1059 to 594 µg/kg) in the 2015 samples. Despite low levels, our analyses showed a trend towards reduced content of DON, ADON, NIV, EnnA, EnnA1, EnnB1 and BEA after removing the small kernel fraction in samples from 2015. For several of the mycotoxins, the concentrations were considerably higher in the small kernel fraction compared to unsorted grain. Our results demonstrate that the level of mycotoxins in unprocessed oat grain can be reduced by removing small kernels. We assume that our study is the first report on the effect of size sorting on the content of enniatins (Enns), NIV and BEA in oat grains.

Composition and Predominance of Fusarium Species Causing Fusarium Head Blight in Winter Wheat Grain Depending on Cultivar Susceptibility and Meteorological Factors

Fusarium head blight (FHB) is one of the most important diseases of wheat, causing yield losses and mycotoxin contamination of harvested grain. A complex of different toxigenic Fusarium species is responsible for FHB and the composition and predominance of species within the FHB complex are determined by meteorological and agronomic factors. In this study, grain of three different susceptible winter wheat cultivars from seven locations in northern Germany were analysed within a five-year survey from 2013 to 2017 by quantifying DNA amounts of different species within the Fusarium community as well as deoxynivalenol (DON) and zearalenone (ZEA) concentrations. Several Fusarium species co-occur in wheat grain samples in all years and cultivars. F. graminearum was the most prevalent species, followed by F. culmorum, F. avenaceum and F. poae, while F. tricinctum and F. langsethiae played only a subordinate role in the FHB complex in terms of DNA amounts. In all cultivars, a comparable year-specific quantitative occurrence of the six detected species and mycotoxin concentrations were found, but with decreased DNA amounts and mycotoxin concentrations in the more tolerant cultivars, especially in years with higher disease pressure. In all years, similar percentages of DNA amounts of the six species to the total Fusarium DNA amount of all detected species were found between the three cultivars for each species, with F. graminearum being the most dominant species. Differences in DNA amounts and DON and ZEA concentrations between growing seasons depended mainly on moisture factors during flowering of wheat, while high precipitation and relative humidity were the crucial meteorological factors for infection of wheat grain by Fusarium. Highly positive correlations were found between the meteorological variables precipitation and relative humidity and DNA amounts of F. graminearum, DON and ZEA concentrations during flowering, whereas the corresponding correlations were much weaker several days before (heading) and after flowering (early and late milk stage).

Fusarium Head Blight, Mycotoxins and Strategies for Their Reduction

Mycotoxins are secondary metabolites of microscopic fungi, which commonly contaminate cereal grains. Contamination of small-grain cereals and maize with toxic metabolites of fungi, both pathogenic and saprotrophic, is one of the particularly important problems in global agriculture. Fusarium species are among the dangerous cereal pathogens with a high toxicity potential. Secondary metabolites of these fungi, such as deoxynivalenol, zearalenone and fumonisin B1 are among five most important mycotoxins on a European and world scale. The use of various methods to limit the development of Fusarium cereal head diseases and grain contamination with mycotoxins, before and after harvest, is an important element of sustainable agriculture and production of safe food. The applied strategies utilize chemical and non-chemical methods, including agronomic, physical and biological treatments. Biological methods now occupy a special place in plant protection as an element of biocontrol of fungal pathogens by inhibiting their development and reducing mycotoxins in grain. According to the literature, Good Agricultural Practices are the best line of defense for controlling Fusarium toxin contamination of cereal and maize grains. However, fluctuations in weather conditions can significantly reduce the effectiveness of plants protection methods against infection with Fusarium spp. and grain accumulation of mycotoxins.

Advances in Occurrence, Importance, and Mycotoxin Control Strategies: Prevention and Detoxification in Foods

Mycotoxins are toxic substances that can infect many foods with carcinogenic, genotoxic, teratogenic, nephrotoxic, and hepatotoxic effects. Mycotoxin contamination of foodstuffs causes diseases worldwide. The major classes of mycotoxins that are of the greatest agroeconomic importance are aflatoxins, ochratoxins, fumonisins, trichothecenes, emerging Fusarium mycotoxins, enniatins, ergot alkaloids, Alternaria toxins, and patulin. Thus, in order to mitigate mycotoxin contamination of foods, many control approaches are used. Prevention, detoxification, and decontamination of mycotoxins can contribute in this purpose in the pre-harvest and post-harvest stages. Therefore, the purpose of the review is to elaborate on the recent advances regarding the occurrence of main mycotoxins in many types of important agricultural products, as well as the methods of inactivation and detoxification of foods from mycotoxins in order to reduce or fully eliminate them.

Genome-wide Association Study and Genomic Prediction for Fusarium graminearum Resistance Traits in Nordic Oat (Avena sativa L.)

Fusarium head blight (FHB) and the accumulation of deoxynivalenol (DON) mycotoxin induced by Fusarium graminearum and other Fusarium fungi cause serious problems for oat production in the Nordic region (Scandinavia, Fennoscandia). Besides toxin accumulation, FHB causes reduction in grain yield and in germination capacity. Here, genomic approaches for accelerating breeding efforts against FHB and DON accumulation were studied. Resistance-related traits included DON content, F. graminearum DNA (relative to oat DNA) content (qFUSG) measured with real-time quantitative polymerase chain reaction (PCR), Fusarium-infected kernels (FIKs) and germination capacity (GC). Plant germplasm used in the study consisted of mostly breeding lines, and additionally, a few cultivars and exotic accessions. Genome-wide association study (GWAS) and genomic prediction, enabling genomic selection (GS) on the resistance-related and collected agronomic traits, were performed. Considerable genetic correlations between resistance-related traits were observed: DON content had a positive correlation (0.60) with qFUSG and a negative correlation (−0.63) with germination capacity. With the material in hand, we were not able to find any significant associations between markers and resistance-related traits. On the other hand, in genomic prediction, some resistance-related traits showed favorable accuracy in fivefold cross-validation (GC = 0.57). Genomic prediction is a promising method and genomic estimated breeding values (GEBVs) generated for germination capacity are applicable in oat breeding programs.

Trichothecenes in Cereal Grains - An Update

Trichothecenes are sesquiterpenoid mycotoxins produced by fungi from the order Hypocreales, including members of the Fusarium genus that infect cereal grain crops. Different trichothecene-producing Fusarium species and strains have different trichothecene chemotypes belonging to the Type A and B class. These fungi cause a disease of small grain cereals, called Fusarium head blight, and their toxins contaminate host tissues. As potent inhibitors of eukaryotic protein synthesis, trichothecenes pose a health risk to human and animal consumers of infected cereal grains. In 2009, Foroud and Eudes published a review of trichothecenes in cereal grains for human consumption. As an update to this review, the work herein provides a comprehensive and multi-disciplinary review of the Fusarium trichothecenes covering topics in chemistry and biochemistry, pathogen biology, trichothecene toxicity, molecular mechanisms of resistance or detoxification, genetics of resistance and breeding strategies to reduce their contamination of wheat and barley.

Association of Cereal, Gluten, and Dietary Fiber Intake With Islet Autoimmunity and Type 1 Diabetes

IMPORTANCE

Dietary proteins, such as gluten, have been suggested as triggers of the disease process in type 1 diabetes (T1D).

OBJECTIVE

To study the associations of cereal, gluten, and dietary fiber intake with the development of islet autoimmunity (IA) and T1D.

DESIGN, SETTING, AND PARTICIPANTS

The prospective birth cohort Finnish Type 1 Diabetes Prediction and Prevention Study recruited children with genetic susceptibility to type 1 diabetes from September 1996 to September 2004 from 2 university hospitals in Finland and followed up every 3 to 12 months up to 6 years for diet, islet autoantibodies, and T1D. Altogether 6081 infants (78% of those invited) participated in the study. Dietary data were available for 5714 children (94.0%) and dietary and IA data were available for 5545 children (91.2%), of whom 3762 (68%) had data on islet autoantibodies up to age 6 years. Information on T1D was available for all children. Data were analyzed in 2018 and end point data were updated in 2015.

EXPOSURES

Each child's intake of cereals, gluten, and dietary fiber was calculated from repeated 3-day food records up to 6 years.

MAIN OUTCOMES AND MEASURES

Islet autoimmunity was defined as repeated positivity for islet cell antibodies and at least 1 biochemical autoantibody of 3 analyzed, or T1D. Data on the diagnosis of T1D were obtained from Finnish Pediatric Diabetes Register.

RESULTS

Of 5545 children (2950 boys [53.2%]), 246 (4.4%) developed IA and of 5714 children (3033 boys [53.1%]), 90 (1.6%) developed T1D during the 6-year follow-up. Based on joint models, the intake of oats (hazard ratio [HR], 1.08; 95% CI, 1.03-1.13), wheat (HR, 1.09; 95% CI, 1.03-1.15), rye (HR, 1.13; 95% CI, 1.03-1.23), gluten-containing cereals (HR, 1.07; 95% CI, 1.03-1.11), gluten without avenin from oats (HR, 2.23; 95% CI, 1.40-3.57), gluten with avenin (HR, 2.06; 95% CI, 1.45-2.92), and dietary fiber (HR, 1.41; 95% CI, 1.10-1.81) was associated with the risk of developing IA (HRs for 1 g/MJ increase in intake). The intake of oats (HR, 1.10; 95% CI, 1.00-1.21) and rye (HR, 1.20; 95% CI, 1.03-1.41) was associated with the risk of developing T1D. After multiple testing correction, the associations with IA remained statistically significant.

CONCLUSIONS AND RELEVANCE

A high intake of oats, gluten-containing cereals, gluten, and dietary fiber was associated with an increased risk of IA. Further studies are needed to confirm or rule out the findings and study potential mechanisms.

Twenty-Eight Fungal Secondary Metabolites Detected in Pig Feed Samples: Their Occurrence, Relevance and Cytotoxic Effects In Vitro

Feed samples are frequently contaminated by a wide range of chemically diverse natural products, which can be determined using highly sensitive analytical techniques. Next to already well-investigated mycotoxins, unknown or unregulated fungal secondary metabolites have also been found, some of which at significant concentrations. In our study, 1141 pig feed samples were analyzed for more than 800 secondary fungal metabolites using the same LC-MS/MS method and ranked according to their prevalence. Effects on the viability of the 28 most relevant were tested on an intestinal porcine epithelial cell line (IPEC-J2). The most frequently occurring compounds were determined as being cyclo-(L-Pro-L-Tyr), moniliformin, and enniatin B, followed by enniatin B1, aurofusarin, culmorin, and enniatin A1. The main mycotoxins, deoxynivalenol and zearalenone, were found only at ranks 8 and 10. Regarding cytotoxicity, apicidin, gliotoxin, bikaverin, and beauvericin led to lower IC50 values, between 0.52 and 2.43 µM, compared to deoxynivalenol (IC50 = 2.55 µM). Significant cytotoxic effects were also seen for the group of enniatins, which occurred in up to 82.2% of the feed samples. Our study gives an overall insight into the amount of fungal secondary metabolites found in pig feed samples compared to their cytotoxic effects in vitro.

A multi-year survey of mycotoxins and ergosterol in Canadian oats

Canadian oat harvest samples, deliveries to processors, and train shipments from primary elevators were collected from mid-2014 through mid-2017 and analyzed for 26 mycotoxins and the fungal biomarker ergosterol. Of the 26 mycotoxins, 7 were not detected in any sample. The most frequently measured mycotoxins were beauvericin (in over 95% of samples analyzed), followed by tentoxin, culmorin, alternariol, alternariol methyl ether, and deoxynivalenol. Median concentrations of the Fusarium-produced mycotoxins ranged from 68 to 1142 μg/kg for deoxynivalenol, 39 to 188 μg/kg for HT-2 and T-2 toxins, 66 to 232 μg/kg for nivalenol, and less than 35 μg/kg for beauvericin. Median concentrations of the sum of Alternaria-produced mycotoxins were all less than 250 μg/kg. Concentrations of analytes varied among years, as well as among growing areas, for the harvest samples. Ergosterol, Fusarium, and Alternaria mycotoxin concentrations appeared to increase from the west toward the eastern Prairies and the province of Quebec; the differences were not statistically significant though. Ochratoxin A in deliveries and train shipments showed annual cyclic increases in the late summer. The results of the survey demonstrate the general compliance of Canadian oats with existing maximum levels for mycotoxins and indicate that in late summer and in years with increased Fusarium infection, there can be a need for monitoring of ochratoxin A and deoxynivalenol, respectively, to mitigate risks of noncompliant grain.

Prevalent Mycotoxins in Animal Feed: Occurrence and Analytical Methods

Today, we have been witnessing a steady tendency in the increase of global demand for maize, wheat, soybeans, and their products due to the steady growth and strengthening of the livestock industry. Thus, animal feed safety has gradually become more important, with mycotoxins representing one of the most significant hazards. Mycotoxins comprise different classes of secondary metabolites of molds. With regard to animal feed, aflatoxins, fumonisins, ochratoxins, trichothecenes, and zearalenone are the more prevalent ones. In this review, several constraints posed by these contaminants at economical and commercial levels will be discussed, along with the legislation established in the European Union to restrict mycotoxins levels in animal feed. In addition, the occurrence of legislated mycotoxins in raw materials and their by-products for the feeds of interest, as well as in the feeds, will be reviewed. Finally, an overview of the different sample pretreatment and detection techniques reported for mycotoxin analysis will be presented, the main weaknesses of current methods will be highlighted.

Amylose-Free ("waxy") Wheat Colonization by Fusarium spp. and Response to Fusarium Head Blight

Hexaploid waxy wheat (Triticum aestivum L.) has null mutations in Wx genes and grain lacking amylose with increased digestibility and usability for specialty foods. The waxy cultivar Mattern is susceptible to Fusarium head blight (FHB) caused by Fusarium graminearum species complex, which produces the mycotoxin deoxynivalenol (DON). In experiment 1, conducted during low natural FHB, grain from waxy breeding lines, Mattern, and wild-type breeding lines and cultivars were assessed for Fusarium infection and DON concentration. Nine Fusarium species and species complexes were detected from internally infected (disinfested) grain; F. graminearum infections were not different between waxy and wild-type. Surface- and internally infected grain (nondisinfested) had greater numbers of Fusarium isolates across waxy versus wild-type, but F. graminearum-like infections were similar; however, DON levels were higher in waxy. In experiment 2, conducted during a timely epidemic, disease severity, Fusarium-damaged kernels (FDK), and DON were assessed for waxy breeding lines, Mattern, and wild-type cultivars. Disease severity and FDK were not significantly different from wild-type, but DON was higher in waxy than wild-type lines. Across both experiments, waxy breeding lines, Plant Introductions 677876 and 677877, responded similarly to FHB as moderately resistant wild-type cultivar Overland, showing promise for breeding advanced waxy cultivars with reduced FHB susceptibility.

Metabarcoding targeting the EF1 alpha region to assess Fusarium diversity on cereals

Fusarium head blight (FHB) is a major cereal disease caused by a complex of Fusarium species. These species vary in importance depending on climatic conditions, agronomic factors or host genotype. In addition, Fusarium species can release toxic secondary metabolites. These mycotoxins constitute a significant food safety concern as they have health implications in both humans and animals. The Fusarium species involved in FHB differ in their pathogenicity, ability to produce mycotoxins, and fungicide sensitivity. Accurate and exhaustive identification of Fusarium species in planta is therefore of great importance. In this study, using a new set of primers targeting the EF1α gene, the diversity of Fusarium species on cereals was evaluated using Illumina high-throughput sequencing. The PCR amplification parameters and bioinformatic pipeline were optimized with mock and artificially infected grain communities and further tested on 65 field samples. Fusarium species were retrieved from mock communities and good reproducibility between different runs or PCR cycle numbers was be observed. The method enabled the detection of as few as one single Fusarium-infected grain in 10,000. Up to 17 different Fusarium species were detected in field samples of barley, durum and soft wheat harvested in France. This new set of primers enables the assessment of Fusarium diversity by high-throughput sequencing on cereal samples. It provides a more exhaustive picture of the Fusarium community than the currently used techniques based on isolation or species-specific PCR detection. This new experimental approach may be used to show changes in the composition of the Fusarium complex or to detect the emergence of new Fusarium species as far as the EF1α sequence of these species show a sufficient amount of polymorphism in the portion of sequence analyzed. Information on the distribution and prevalence of the different Fusarium species in a given geographical area, and in response to various environmental factors, is of great interest for managing the disease and predicting mycotoxin contamination risks.

Assessment of Toxigenic Fusarium Species and Their Mycotoxins in Brewing Barley Grains

Fusarium species threaten yield and quality of cereals worldwide due to their ability to produce mycotoxins and cause plant diseases. Trichothecenes and zearalenone are the most economically significant mycotoxins and are of particular concern in barley, maize and wheat. For this reason, the aim of this study was to characterize the Fusarium isolates from brewing barley and to assess deoxynivalenol and zearalenone contamination in grains. Characterization of the Fusarium strains was carried out by the phylogeny based on two loci (EF-1α and RPB2). Mycotoxin detection and quantification were performed by LC-MS. The results show that Fusarium was the predominant genus. Phylogenetic study demonstrated that the majority of the strains clustered within the Fusarium sambucinum species complex followed by the Fusarium tricinctum species complex. The results revealed high incidence of deoxynivalenol (DON) and zearalenone (ZEA) contamination (90.6% and 87.5%, respectively). It was observed that 86% of the samples contaminated with ZEA were above the limits set by the EU and Brazilian regulations. These results may highlight the importance of controlling Fusarium toxins in barley, mainly because of its use in the brewing industry and the resistance of various mycotoxins to food processing treatments.

Morphological and Molecular Variation Between Fusarium avenaceum, Fusarium arthrosporioides and Fusarium anguioides Strains

Fusarium avenaceum and closely related species are common fungi on various plants, cultivated in different climatic regions. The aim of this study was to determine the taxonomic affiliations of the F. avenaceum, Fusarium arthrosporioides, and Fusarium anguioides strains by using morphological, physiological and molecular-genetic approaches. Twenty-six single-spored morphologically identified strains, which were mainly from cereals, were investigated in order to find out, if they belong to a separate species. Pathogenicity of strains to wheat seedlings and ISSR (Inter Simple Sequence Repeats) fingerprint and beta-tubulin DNA sequence patterns were analyzed. According to phylogenetic analyses, the strains could be divided into two big groups consisting of mostly F. avenaceum or F. anguioides strains. F. arthrosporioides was not detected as a separate species by the sum of the characters. F. anguioides was characterized as a separate species, which could be identified by morphological and molecular data. High genetic diversity of the F. avenaceum and related species was revealed. One F. anguioides strain (rudbeckia, Vladivostok, Russia), had an identical beta-tubulin sequence with two previously sequenced strains of Fusarium tricinctum species complex, which were isolated from dicotyledonous plants in Asia.

A Review on the Synthesis and Bioactivity Aspects of Beauvericin, a Fusarium Mycotoxin

Beauvericin (BEA) is an emerging Fusarium mycotoxin that contaminates food and feeds globally. BEA biosynthesis is rapidly catalyzed by BEA synthetase through a nonribosomal, thiol-templated mechanism. This mycotoxin has cytotoxicity and is capable of increasing oxidative stress to induce cell apoptosis. Recently, large evidence further shows that this mycotoxin has a variety of biological activities and is being considered a potential candidate for medicinal and pesticide research. It is noteworthy that BEA is a potential anticancer agent since it can increase the intracellular Ca²⁺ levels and induce the cancer cell death through oxidative stress and apoptosis. BEA has exhibited effective antibacterial activities against both pathogenic Gram-positive and Gram-negative bacteria. Importantly, BEA exhibits an effective capacity to inhibit the human immunodeficiency virus type-1 integrase. Moreover, BEA can simultaneously target drug resistance and morphogenesis which provides a promising strategy to combat life-threatening fungal infections. Thus, in this review, the synthesis and the biological activities of BEA, as well as, the underlying mechanisms, are fully analyzed. The risk assessment of BEA in food and feed are also discussed. We hope this review will help to further understand the biological activities of BEA and cast some new light on drug discovery.

Comparative in vitro cytotoxicity of the emerging Fusarium mycotoxins beauvericin and enniatins to porcine intestinal epithelial cells

The emerging Fusarium mycotoxins beauvericin (BEA) and enniatin (ENN) A, ENN A1, ENN B and ENN B1 gain increasing interest due to their highly prevalent contamination of cereals and cereal products. After oral intake, the gastro-intestinal tract is the first possible site of interaction. In the present in vitro study, the relative cytotoxicity of these mycotoxins towards proliferating and differentiated intestinal porcine epithelial cells of the jejunum (IPEC-J2) was evaluated using flow cytometric viability analysis. IPEC-J2 cells showed the highest sensitivity to BEA and ENN A. In proliferating cells, incubation for 24h with 10 μM BEA caused complete disruption, while the viability percentage declined to 32% after 24h of incubation with 10 μM ENN A. ENN A1 and ENN B1 were less cytotoxic with 87% and 93% viable cells after 24h of incubation with 10 μM ENN A1 and B1, respectively. ENN B was the least cytotoxic since incubation at concentrations up to 100 μM resulted in 83% viable proliferating cells. The same trend was observed for differentiated cells. The limited in vitro cytotoxic effect of ENN B on intestinal cells corroborates previous in vivo findings in broiler chicken in which dietary ENN B had minimal effect on intestinal morphometry.