Influence of agricultural practices on fusarium infection of cereals and subsequent contamination of grain by trichothecene mycotoxins

A winged-helix DNA-binding protein is essential for self-fertility during sexual development of the homothallic fungus Fusarium graminearum

Sexual reproduction is crucial for increasing the genetic diversity of populations and providing overwintering structures, such as perithecia and associated tissue, in the destructive plant pathogenic fungus Fusarium graminearum. While mating-type genes serve as master regulators in fungal sexual reproduction, the molecular mechanisms underlying this process remain elusive. Winged-helix DNA-binding proteins are key regulators of embryogenesis and cell differentiation in higher eukaryotes. These proteins are implicated in the morphogenesis and development of several fungal species. However, their involvement in sexual reproduction remains largely unexplored in F. graminearum. Here, we investigated the function of winged-helix DNA-binding proteins in vegetative growth, conidiation, and sexual reproduction, with a specific focus on the FgWING27, which is highly conserved among Fusarium species. Deletion of FgWING27 resulted in an abnormal pattern characterized by a gradual increase in the expression of mating-type genes during sexual development, indicating its crucial role in the stage-specific genetic regulation of MAT genes in the late stages of sexual development. Furthermore, using chromatin immunoprecipitation followed by sequencing analysis, we identified Fg17056 as a downstream gene of Fgwing27, which is essential for sexual reproduction. These findings underscore the significance of winged-helix DNA-binding proteins in fungal development and reproduction in F. graminearum, and highlight the pivotal role of Fgwing27 as a core genetic factor in the intricate genetic regulatory network governing sexual reproduction.IMPORTANCEFusarium graminearum is a devastating plant pathogenic fungus causing significant economic losses due to reduced crop yields. In Fusarium Head Blight epidemics, spores produced through sexual and asexual reproduction serve as inoculum, making it essential to understand the fungal reproduction process. Here, we focus on winged-helix DNA-binding proteins, which have been reported to play crucial roles in cell cycle regulation and differentiation, and address their requirement in the sexual reproduction of F. graminearum. Furthermore, we identified a highly conserved protein in Fusarium as a key factor in self-fertility, along with the discovery of its direct downstream genes. This provides crucial information for constructing the complex genetic regulatory network of sexual reproduction and significantly contribute to further research on sexual reproduction in Fusarium species.

Unintended food safety impacts of agricultural circular economies, with case studies in arsenic and mycotoxins

For millennia, food systems worldwide have employed practices befitting a circular economy: recycling of agricultural and food waste or byproducts, environmentally sustainable production methods, and food preservation to reduce waste. Many modern-day agricultural practices may also contribute to a circular economy through the reuse of waste products and/or reducing agricultural inputs. There are, however, food safety impacts. This paper describes two sustainable agricultural practices that have unintended positive and negative impacts on food safety: alternative rice cultivation practices and no-till agriculture. We highlight how alternative rice cultivation practices have intended benefits of water conservation and economic savings, yet also unintended effects on food safety by reducing foodborne arsenic levels while increasing cadmium levels. No-till agriculture reduces soil erosion and repurposes crop residues, but can lead to increased foodborne mycotoxin levels. Trade-offs, future research, and policy recommendations are discussed as we explore the duality of sustainable agricultural practices and food safety.

Machine Learning Applied to the Detection of Mycotoxin in Food: A Systematic Review

Mycotoxins, toxic secondary metabolites produced by certain fungi, pose significant threats to global food safety and public health. These compounds can contaminate a variety of crops, leading to economic losses and health risks to both humans and animals. Traditional lab analysis methods for mycotoxin detection can be time-consuming and may not always be suitable for large-scale screenings. However, in recent years, machine learning (ML) methods have gained popularity for use in the detection of mycotoxins and in the food safety industry in general due to their accurate and timely predictions. We provide a systematic review on some of the recent ML applications for detecting/predicting the presence of mycotoxin on a variety of food ingredients, highlighting their advantages, challenges, and potential for future advancements. We address the need for reproducibility and transparency in ML research through open access to data and code. An observation from our findings is the frequent lack of detailed reporting on hyperparameters in many studies and a lack of open source code, which raises concerns about the reproducibility and optimisation of the ML models used. The findings reveal that while the majority of studies predominantly utilised neural networks for mycotoxin detection, there was a notable diversity in the types of neural network architectures employed, with convolutional neural networks being the most popular.

Effect of DON and ZEN and their metabolites DOM-1 and HZEN on B cell proliferation and antibody production

Introduction

The mycotoxins deoxynivalenol (DON) and zearalenone (ZEN), produced by Fusarium fungi, are frequently found in the cereal-rich diet of pigs and can modulate the immune system. Some enzymes or bacteria present in the digestive tract can de-epoxydize DON to deepoxy-deoxynivalenol (DOM-1) and biotransform ZEN into hydrolyzed ZEN (HZEN). The effects of these metabolites on immune cells, particularly with respect to the vaccine responses, are poorly documented. The aim of this study was to address the impact of DON and ZEN and their respective derivatives, on proliferation, and antibody production of porcine B cells in vitro.

Methods

Peripheral blood mononuclear cells (PBMCs), isolated from healthy pigs, were stimulated with the Toll-like receptor (TLR) 7/8-agonist Resiquimod (R848) or the TLR/1/2-agonist Pam3Cys-SKKKK in combination with DON [0.1-1.6 µM] or DOM-1 [1.6 µM and 16 µM] and ZEN [2.5-40 µM] or HZEN [40 µM].

Results

A strong decrease in B-cell proliferation was observed at DON concentrations equal to or exceeding 0.8 µM and at ZEN concentrations equal to or exceeding 20 µM. Treatment with 1.6 µM DON or 40 µM ZEN led to almost a complete loss of live CD79α+ B cells. Moreover, CD21 expression of proliferating IgG+ and IgM+ B-cell subsets was decreased at DON concentrations equal to and exceeding 0.4 µM and at ZEN concentrations equal to or exceeding 10 µM. ELISpot assays revealed a decrease of IgG-secreting B cells at concentrations of and exceeding 0.4 µM and at ZEN concentrations equal to and exceeding 10 µM. ELISA assays showed a decrease of IgM, IgG, and IgA secretion at concentrations equal to or exceeding 0.4 µM DON. ZEN reduced IgM secretion at 20-40 µM (both R848 and Pam3Cys-SKKKK), IgG secretion at 40 µM (both R848 and Pam3Cys-SKKKK) and IgA secretion at 20-40 µM.

Discussion

Our in vitro experiments show that while DON and ZEN impair immunoglobulin production and B-cell proliferation, this effect is abrogated by HZEN and DOM-1.

What Is Fusarium Head Blight (FHB) Resistance and What Are Its Food Safety Risks in Wheat? Problems and Solutions-A Review

The term "Fusarium Head Blight" (FHB) resistance supposedly covers common resistances to different Fusarium spp. without any generally accepted evidence. For food safety, all should be considered with their toxins, except for deoxynivalenol (DON). Disease index (DI), scabby kernels (FDK), and DON steadily result from FHB, and even the genetic regulation of Fusarium spp. may differ; therefore, multitoxin contamination is common. The resistance types of FHB form a rather complex syndrome that has been the subject of debate for decades. It seems that resistance types are not independent variables but rather a series of components that follow disease and epidemic development; their genetic regulation may differ. Spraying inoculation (Type 1 resistance) includes the phase where spores land on palea and lemma and spread to the ovarium and also includes the spread-inhibiting resistance factor; therefore, it provides the overall resistance that is needed. A significant part of Type 1-resistant QTLs could, therefore, be Type 2, requiring the retesting of the QTLs; this is, at least, the case for the most effective ones. The updated resistance components are as follows: Component 1 is overall resistance, as discussed above; Component 2 includes spreading from the ovarium through the head, which is a part of Component 1; Component 3 includes factors from grain development to ripening (FDK); Component 4 includes factors influencing DON contamination, decrease, overproduction, and relative toxin resistance; and for Component 5, the tolerance has a low significance without new results. Independent QTLs with different functions can be identified for one or more traits. Resistance to different Fusarium spp. seems to be connected; it is species non-specific, but further research is necessary. Their toxin relations are unknown. DI, FDK, and DON should be checked as they serve as the basic data for the risk analysis of cultivars. A better understanding of the multitoxin risk is needed regarding resistance to the main Fusarium spp.; therefore, an updated testing methodology is suggested. This will provide more precise data for research, genetics, and variety registration. In winter and spring wheat, the existing resistance level is very high, close to Sumai 3, and provides much greater food safety combined with sophisticated fungicide preventive control and other practices in commercial production.

Effect of Fungicide Treatment on Multi-Mycotoxin Occurrence in French Wheat during a 4-Year Period

Wheat represents one of the most widely consumed cereals worldwide. Cultivated in winter and spring, it is vulnerable to an array of different pathogens, including fungi, which are managed largely through the in-field application of fungicides. During this study, a 4-year field investigation (2018-2021) was performed in France, aiming to assess the efficacy of fungicide treatment to reduce mycotoxin contamination in common and durum wheat. Several different commercially available fungicides were applied via sprayers. Concentrations of mycotoxins and fungal metabolites in wheat were determined using a multi-analyte liquid-chromatography-tandem-mass-spectrometry-based method. The highest contamination levels and strongest effects of fungicides were observed in 2018, followed by 2021. A significant fungicide-mediated reduction was observed for the trichothecenes deoxynivalenol, deoxynivalenol-3-glucoside, nivalenol, and nivalenol-3-glucoside. Furthermore, fungicide treatment also reduced levels of culmorin and its hydroxy metabolites 5- and 15-hydroxy-culmorin, as well as aurofusarin. Interestingly, the Alternaria metabolite infectopyron was increased following fungicide treatment. In conclusion, fungicide treatment was effective in reducing mycotoxin levels in wheat. However, as complete prevention of mycotoxin contamination was not achieved, fungicide treatment should always be combined with other pre- and post-harvest mycotoxin mitigation strategies to improve food and feed safety.

Free and Modified Mycotoxins in Organic and Conventional Oats (Avena sativa L.) Grown in Scotland

Small grain cereals are frequently infected with mycotoxigenic Fusarium fungi. Oats have a particularly high risk of contamination with type A trichothecene mycotoxins; their glucoside conjugates have also been reported. Agronomy practices, cereal variety and weather conditions have been suggested to play a role in Fusarium infection in oats. The current study investigates concentrations of free and conjugated Fusarium mycotoxins in organic and conventional oats grown in Scotland. In 2019, 33 milling oat samples (12 organic, 21 conventional) were collected from farmers across Scotland, together with sample questionnaires. Samples were analysed for 12 mycotoxins (type A trichothecenes T-2-toxin, HT-2-toxin, diacetoxyscirpenol; type B trichothecenes deoxynivalenol, nivalenol; zearalenone and their respective glucosides) using LC-MS/MS. The prevalence of type A trichothecenes T-2/HT-2 was very high (100% of conventional oats, 83% of organic oats), whereas type B trichothecenes were less prevalent, and zearalenone was rarely found. T-2-glucoside and deoxynivalenol-glucoside were the most prevalent conjugated mycotoxins (36 and 33%), and co-occurrence between type A and B trichothecenes were frequently observed (66% of samples). Organic oats were contaminated at significantly lower average concentrations than conventional oats, whereas the effect of weather parameters were not statistically significant. Our results clearly indicate that free and conjugated T-2- and HT-2-toxins pose a major risk to Scottish oat production and that organic production and crop rotation offer potential mitigation strategies.

Application of direct PCR for phylogenetic analysis of Fusarium fujikuroi species complex isolated from rice seeds

Plant pathogenic fungi cause severe yield losses and mycotoxin contamination in crops. The precise and rapid detection of fungal pathogens is essential for effective disease management. Sequencing universal DNA barcodes has become the standard method for the diagnosis of fungal diseases, as well as for identification and phylogenetic analysis. A major bottleneck in obtaining DNA sequence data from many samples was the laborious and time-consuming process of sample preparation for genomic DNA. Here, we describe a direct PCR approach that bypasses the DNA extraction steps to streamline the molecular identification of fungal species. Using a direct PCR approach, we successfully sequenced the nuclear ribosomal internal transcribed spacer (ITS) region for the representatives of major fungal lineages. To demonstrate the usefulness of this approach, we performed a phylogenetic analysis of the Fusarium fujikuroi species complex, which causes bakanae ("foolish seedling") disease of rice and mycotoxin contamination. A total of 28 candidate strains were isolated from rice seeds in the Republic of Korea, and the identity of the isolates was determined using the DNA sequence of both ITS and translation elongation factor 1-α regions. In addition, 17 F. fujikuroi isolates were examined for fumonisin (FB) production in rice medium using an enzyme-linked immunosorbent assay. Phylogenetic and toxigenic analyses showed that the F. fujikuroi strains could be distinguished into two groups: FB producers (B14-type) and non-producers (B20-type). These results will accelerate the molecular identification of fungal pathogens and facilitate the effective management of fungal diseases.

Reduced Risk of Oat Grain Contamination with Fusarium langsethiae and HT-2 and T-2 Toxins with Increasing Tillage Intensity

Frequent occurrences of high levels of Fusarium mycotoxins have been recorded in Norwegian oat grain. To elucidate the influence of tillage operations on the development of Fusarium and mycotoxins in oat grain, we conducted tillage trials with continuous oats at two locations in southeast Norway. We have previously presented the content of Fusarium DNA detected in straw residues and air samples from these fields. Grain harvested from ploughed plots had lower levels of Fusarium langsethiae DNA and HT-2 and T-2 toxins (HT2 + T2) compared to grain from harrowed plots. Our results indicate that the risk of F. langsethiae and HT2 + T2 contamination of oats is reduced with increasing tillage intensity. No distinct influence of tillage on the DNA concentration of Fusarium graminearum and Fusarium avenaceum in the harvested grain was observed. In contrast to F. graminearum and F. avenaceum, only limited contents of F. langsethiae DNA were observed in straw residues and air samples. Still, considerable concentrations of F. langsethiae DNA and HT2 + T2 were recorded in oat grain harvested from these fields. We speculate that the life cycle of F. langsethiae differs from those of F. graminearum and F. avenaceum with regard to survival, inoculum production and dispersal.

Influence of Agronomic Factors on Mycotoxin Contamination in Maize and Changes during a 10-Day Harvest-Till-Drying Simulation Period: A Different Perspective

Agronomic factors can affect mycotoxin contamination of maize, one of the most produced cereals. Maize is usually harvested at 18% moisture, but it is not microbiologically stable until it reaches 14% moisture at the drying plants. We studied how three agronomic factors (crop diversification, tillage system and nitrogen fertilization rate) can affect fungal and mycotoxin contamination (deoxynivalenol and fumonisins B₁ and B₂) in maize at harvest. In addition, changes in maize during a simulated harvest-till-drying period were studied. DON content at harvest was higher for maize under intensive tillage than using direct drilling (2695 and 474 μg kg⁻¹, respectively). We found two reasons for this: (i) soil crusting in intensive tillage plots caused the formation of pools of water that created high air humidity conditions, favouring the development of DON-producing moulds; (ii) the population of Lumbricus terrestris, an earthworm that would indirectly minimize fungal infection and mycotoxin production on maize kernels, is reduced in intensive tillage plots. Therefore, direct drilling is a better approach than intensive tillage for both preventing DON contamination and preserving soil quality. Concerning the simulated harvest-till-drying period, DON significantly increased between storage days 0 and 5. Water activity dropped on the 4th day, below the threshold for DON production (around 0.91). From our perspective, this study constitutes a step forward towards understanding the relationships between agronomic factors and mycotoxin contamination in maize, and towards improving food safety.

Association between forage mycotoxins and liver disease in horses

Background

Outbreaks of liver disease in horses are common but the etiology of most remains unknown. Forage mycotoxins have been suspected to be a cause.

Objectives

To examine the association between outbreaks of liver disease and the presence of mycotoxins in forage stored on the same premises.

Animals

Premises were identified where ≥4 horses were contemporaneously affected by liver disease, and a control group was formed from premises where ≥4 horses had been examined and found to have no evidence of liver disease.

Methods

Forage was collected from 29 case and 12 control premises. The forage was analyzed for mycotoxin content using a liquid chromatography/mass spectrometry method, targeting 54 mycotoxins. The presence and distribution of mycotoxins between case and control samples was compared.

Results

Mycotoxins were found in 23/29 (79%) case samples and 10/12 (83%) control samples (P > .99; relative risk, 0.93; 95% confidence interval [CI], 0.64‐1.75). Median (interquartile range [IQR]) total mycotoxin concentration was similar in case and control samples (85.8 μg/kg [1.6‐268] vs. 315 μg/kg [6.3‐860]; P = .16). Ten mycotoxins were found exclusively in case premises comprising fumonisin B1, 15‐acetyldeoxynivalenol, deoxynivalenol, zearalenone, aflatoxins B1 and G1, methylergonovine, nivalenol, verruculogen, and wortmannin. The median (IQR) concentration of fumonisin B1 was significantly higher in case versus control samples (0 μg/kg [0‐81.7] vs. 0 μg/kg [0‐0]; P = .04).

Conclusions and Clinical Importance

Several mycotoxins with known hepatotoxic potential were found, alone or in combination, exclusively at case premises, consistent with the hypothesis that forage‐associated mycotoxicosis may be a cause of outbreaks of liver disease in horses in the United Kingdom.

Impact of agronomic practices on Fusarium mycotoxin accumulation in maize grain

In the Great Lakes region of North America, Gibberella ear rot (GER), caused by Fusarium graminearum, affects grain quality due to the accumulation of mycotoxins. GER severity is strongly influenced by environmental conditions; however, agronomic practices can also influence disease severity and mycotoxin accumulation. In this study, three separate small-plot experiments were conducted at Ridgetown, ON, Canada during 2019 and 2020 under an inoculated-misted system to determine Fusarium mycotoxin accumulation as affected by: (1) plant population density; (2) in-row-plant developmental variability; and (3) the effect of integrated Bt refuge genetics. In this study, DON concentrations were at least 49% higher in maize at 113,600 plants/ha compared to 79,000 plants/ha. Moreover, mycotoxin accumulation was higher in plants that were delayed developmentally in the crop row; total DON concentrations were at least 310% higher in late silked plants adjacent to early silked plants. Results of the plant population density and in-row-plant developmental variability suggest that the main driver for mycotoxin accumulation was stress induced by plant competition rather than environmental conditions; this highlights the importance of avoiding plant competitive stress as a strategy to reduce the risks of mycotoxin accumulation. In this study, there was no statistical difference in DON accumulation between the Bt component and the non-Bt component in each of the four hybrids tested; however, there was evidence that hybrids varied in susceptibility, including the Bt and non-Bt components that were paired commercially in a bag of seed maize. Reducing mycotoxins in maize requires integrated management, which includes agronomic considerations. These results indicate that mycotoxins are favoured with high plant populations and plant-to-plant variability in the row, especially in susceptible hybrids.

Bioprospecting Phenols as Inhibitors of Trichothecene-Producing Fusarium: Sustainable Approaches to the Management of Wheat Pathogens

Fusarium spp. are ubiquitous fungi able to cause Fusarium head blight and Fusarium foot and root rot on wheat. Among relevant pathogenic species, Fusarium graminearum and Fusarium culmorum cause significant yield and quality loss and result in contamination of the grain with mycotoxins, mainly type B trichothecenes, which are a major health concern for humans and animals. Phenolic compounds of natural origin are being increasingly explored as fungicides on those pathogens. This review summarizes recent research activities related to the antifungal and anti-mycotoxigenic activity of natural phenolic compounds against Fusarium, including studies into the mechanisms of action of major exogenous phenolic inhibitors, their structure-activity interaction, and the combined effect of these compounds with other natural products or with conventional fungicides in mycotoxin modulation. The role of high-throughput analysis tools to decipher key signaling molecules able to modulate the production of mycotoxins and the development of sustainable formulations enhancing potential inhibitors' efficacy are also discussed.

Key Global Actions for Mycotoxin Management in Wheat and Other Small Grains

Mycotoxins in small grains are a significant and long-standing problem. These contaminants may be produced by members of several fungal genera, including Alternaria, Aspergillus, Fusarium, Claviceps, and Penicillium. Interventions that limit contamination can be made both pre-harvest and post-harvest. Many problems and strategies to control them and the toxins they produce are similar regardless of the location at which they are employed, while others are more common in some areas than in others. Increased knowledge of host-plant resistance, better agronomic methods, improved fungicide management, and better storage strategies all have application on a global basis. We summarize the major pre- and post-harvest control strategies currently in use. In the area of pre-harvest, these include resistant host lines, fungicides and their application guided by epidemiological models, and multiple cultural practices. In the area of post-harvest, drying, storage, cleaning and sorting, and some end-product processes were the most important at the global level. We also employed the Nominal Group discussion technique to identify and prioritize potential steps forward and to reduce problems associated with human and animal consumption of these grains. Identifying existing and potentially novel mechanisms to effectively manage mycotoxin problems in these grains is essential to ensure the safety of humans and domesticated animals that consume these grains.

Effect of pydiflumetofen on Gibberella ear rot and Fusarium mycotoxin accumulation in maize grain

In Ontario, Canada, Fusarium graminearum Schwabe causes Gibberella ear rot (GER) in maize, resulting in the accumulation of mycotoxins, mainly deoxynivalenol (DON), DON-3-glucoside (DON-3G) and zearalenone (ZEN) in infected kernels. Fungicides can be an important tool for managing GER and DON and other Fusarium mycotoxins in maize. Until recently, all fungicides available to growers were triazoles, thus no resistance management strategy through fungicide use was possible. In this study, a novel carboxamide fungicide active ingredient (pydiflumetofen) was evaluated against conventional triazole fungicides and mixtures for: (1) effectiveness on mycotoxins (2) optimal application timing; and (3) efficacy of application, with and without an insecticide, under natural and inoculated-misted conditions. The best timing for fungicide application was at full silk, resulting in the highest reduction of GER symptoms and lowest accumulation of F. graminearum mycotoxins in harvested grain. DON and DON-3G concentrations were reduced by at least 50% with a fungicide application at full silk. Fungicide treatments did not affect fumonisin concentrations in grain. Pydiflumetofen (94 g active ingredients (AI)/ha) and fungicides containing pydiflumetofen (75-94 g AI/ha) were similar to standard triazole fungicides (prothioconazole at 200 g AI/ha and metconazole at 90 g AI/ha) for reducing GER and F. graminearum mycotoxins under misted-inoculated plots and commercial field conditions; as a result, we expect pydiflumetofen to be competitive with triazole-only chemistries in the marketplace, which should delay the onset of fungicide resistance.

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.

Fusarium mycotoxin content and Fusarium species presence in Czech organic and conventional wheat

Deoxynivalenol and zearalenone content and the presence of Fusarium species in organically and conventionally grown wheat harvested in the Czech Republic during 2015-2017 were studied. Mycotoxin contamination was compared using two approaches. The first was based on samples taken from randomly selected farms in individual regions of the Czech Republic, both organic (154 samples) and conventional (330 samples). In the second approach, a sample set of conventional wheat compatible with organic one was formed, with samples paired according to the preceding crop and region of harvest. Using the first approach, mycotoxins were shown to be higher in conventional wheat; however, there was no difference in mycotoxin contamination between organic and conventional wheat using the second approach. Eight wheat samples with mycotoxin content above the EU limits were found, seven for deoxynivalenol (2.1%) and one for zearalenone (0.3%), all of them originated from conventional farming system. Six of them had maize as the preceding crop. The presence of five Fusarium species (Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium poae and Fusarium sporotrichioides) was compared for the compatible wheat sample sets (second approach). The predominant species were found to be F. poae and F. graminearum in both the organic and conventional wheat. Harvest year significantly influenced both the occurrence of the main Fusarium species and the level of mycotoxin contamination. The study confirmed that (a) organic farming system was able to keep mycotoxin contamination of wheat at a low level, (b) in studies on the significance of organic/conventional agricultural practice on mycotoxin levels in cereals, it is important to pay attention to common production and environmental variables.

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.

Incentives to Stimulate European Wheat Farmers to Adapt Their Fusarium Species Mycotoxin Management

Fusarium species infection in wheat can lead to Fusarium Head Blight (FHB) and contamination with mycotoxins. To fully exploit more recent insights into FHB and mycotoxin management, farmers might need to adapt their agronomic management, which can be stimulated through incentives. This study aimed to identify incentives to stimulate European farmers to adapt their agronomic management to reduce FHB and related mycotoxins in wheat. A questionnaire was distributed among 224 wheat farmers from Italy, the Netherlands, Serbia, and the United Kingdom. Using the respondents' data, Bayesian Network modelling was applied to estimate the probability that farmers would adapt their current agronomic management under eight different incentives given the conditions set by their farm and farmer characteristics. Results show that most farmers would adapt their current agronomic management under the incentives "paid extra when wheat contains low levels of mycotoxins" and "wheat is tested for the presence of mycotoxins for free". The most effective incentive depended on farm and farmer characteristics, such as country, crop type, size of arable land, soil type, education, and mycotoxin knowledge. Insights into the farmer characteristics related to incentives can help stakeholders in the wheat supply chain, such as farmer cooperatives and the government, to design tailor-made incentive plans.

Contamination of Wheat, Barley, and Maize Seeds with Toxigenic Fusarium Species and Their Mycotoxins in Tunisia

Background

Fusarium is a worldwide distributed fungal genus. It includes different species pathogenic to cereals among others crops. Some of these species can also produce toxic compounds toward animals and humans.

Objective

In this work, occurrence of fumonisins B1+B2, zearalenone, type A trichothecenes (T-2 and HT-2 toxins), and type B trichothecenes (deoxynivalenol[DON] and nivalenol[NIV]) was studied in 65 samples of stored and freshly harvested wheat, barley, and maize collected in Tunisia.

Methods

Mycotoxins analyses were performed by using gas chromatography for type B trichothecenes and HPLC for other mycotoxins. Obtained results were compared with the presence of mycotoxigenic species considered responsible for their synthesis by using species-specific polymerase chain reaction (PCR).

Results

Fumonisins occurred in 20.83% of wheat, 40% of barley, and 57.14% of maize samples, at levels exceeding European limits and suggesting a risk in Tunisian cereals, especially maize. Zearalenone, DON, NIV, and T-2+HT-2 toxins were detected at lower values in only wheat and barley samples. PCR protocols showed the predominance of F. verticillioides especially in maize, and occurrence of F. equiseti and F. graminearum in wheat and barley, and F. proliferatum in only two maize samples. A very consistent correlation was found between the detection of F. verticillioides and the contamination by fumonisins, as well as between the presence of F. graminearum and the contamination by zearalenone, DON, and NIV in the analyzed cereals.

Conclusions

Consequently, the detection of Fusarium species with the current PCR assays strategy in wheat, barley, and maize grains may be considered predictive of their potential mycotoxin risk in these matrices.

Highlights

This work is the first to report information on the occurrence of fumonisins, trichothecene, and ZEN, together with their potentially producing Fusarium species in wheat, barley, and maize in Tunisia. The high level of fumonisins in cereals, especially maize, stresses the importance of the control and the regularization of these mycotoxins for food safety.

Snow mold of winter cereals: a complex disease and a challenge for resistance breeding

Snow mold resistance is a complex quantitative trait highly affected by environmental conditions during winter that must be addressed by resistance breeding. Snow mold resistance in winter cereals is an important trait for many countries in the Northern Hemisphere. The disease is caused by at least four complexes of soilborne fungi and oomycetes of which Microdochium nivale and M. majus are among the most common pathogens. They have a broad host range covering all winter and spring cereals and can basically affect all plant growth stages and organs. Their attack leads to a low germination rate, and/or pre- and post-emergence death of seedlings after winter and, depending on largely unknown environmental conditions, also to foot rot, leaf blight, and head blight. Resistance in winter wheat and triticale is governed by a multitude of quantitative trait loci (QTL) with mainly additive effects highly affected by genotype × environment interaction. Snow mold resistance interacts with winter hardiness in a complex way leading to a co-localization of resistance QTLs with QTLs/genes for freezing tolerance. In practical breeding, a multistep procedure is necessary with (1) freezing tolerance tests, (2) climate chamber tests for snow mold resistance, and (3) field tests in locations with and without regularly occurring snow cover. In the future, resistance sources should be genetically characterized also in rye by QTL mapping or genome-wide association studies. The development of genomic selection procedures should be prioritized in breeding research.

One Biosecurity: a unified concept to integrate human, animal, plant, and environmental health

In the wake of the SARS-CoV-2 pandemic, the world has woken up to the importance of biosecurity and the need to manage international borders. Yet strong sectorial identities exist within biosecurity that are associated with specific international standards, individual economic interests, specific research communities, and unique stakeholder involvement. Despite considerable research addressing human, animal, plant, and environmental health, the science connections between these sectors remain quite limited. One Biosecurity aims to address these limitations at global, national, and local scales. It is an interdisciplinary approach to biosecurity policy and research that builds on the interconnections between human, animal, plant, and environmental health to effectively prevent and mitigate the impacts of invasive alien species. It provides an integrated perspective to address the many biosecurity risks that transcend the traditional boundaries of health, agriculture, and the environment. Individual invasive alien plant and animal species often have multiple impacts across sectors: as hosts of zoonotic parasites, vectors of pathogens, pests of agriculture or forestry, as well as threats to biodiversity and ecosystem function. It is time these risks were addressed in a systematic way. One Biosecurity is essential to address several major sociological and environmental challenges to biosecurity: climate change, increasing urbanisation, agricultural intensification, human global mobility, loss of technical capability as well as public resistance to pesticides and vaccines. One Biosecurity will require the bringing together of taxonomists, population biologists, modellers, economists, chemists, engineers, and social scientists to engage in a new agenda that is shaped by politics, legislation, and public perceptions.

Rye Snow Mold-Associated Microdochium nivale Strains Inhabiting a Common Area: Variability in Genetics, Morphotype, Extracellular Enzymatic Activities, and Virulence

Snow mold is a severe plant disease caused by psychrophilic or psychrotolerant fungi, of which Microdochium species are the most harmful. A clear understanding of Microdochium biology has many gaps; the pathocomplex and its dynamic are poorly characterized, virulence factors are unknown, genome sequences are not available, and the criteria of plant snow mold resistance are not elucidated. Our study aimed to identify comprehensive characteristics of a local community of snow mold-causing Microdochium species colonizing a particular crop culture. By using the next-generation sequencing (NGS) technique, we characterized fungal and bacterial communities of pink snow mold-affected winter rye (Secale cereale) plants within a given geographical location shortly after snowmelt. Twenty-one strains of M. nivale were isolated, classified on the basis of internal transcribed spacer 2 (ITS2) region, and characterized by morphology, synthesis of extracellular enzymes, and virulence. Several types of extracellular enzymatic activities, the level of which had no correlations with the degree of virulence, were revealed for Microdochium species for the first time. Our study shows that genetically and phenotypically diverse M. nivale strains simultaneously colonize winter rye plants within a common area, and each strain is likely to utilize its own, unique strategy to cause the disease using "a personal" pattern of extracellular enzymes.

Factors underlying Dutch farmers' intentions to adapt their agronomic management to reduce Fusarium species infection in wheat

Infection of wheat by Fusarium species can lead to Fusarium Head Blight (FHB) and mycotoxin contamination, thereby reducing food quality and food safety, and leading to economic losses. Agronomic management through the implementation of various pre-harvest measures can reduce the probability of Fusarium spp. infection in the wheat field. To design interventions that could stimulate wheat farmers to (further) improve their agronomic management to reduce FHB, it is key to understand farmers’ behaviour towards adapting their management. The aim of this paper was to understand the intention, underlying behavioural constructs, and beliefs of Dutch wheat farmers to adapt their agronomic management to reduce FHB and mycotoxin contamination in wheat, applying the Theory of Planned Behaviour (TPB). Data were collected from 100 Dutch wheat farmers via a questionnaire. The standard TPB analysis was extended with an assessment of the robustness of the belief results to account for the statistical validity of the analysis on TPB beliefs (i.e. to address the so-called expectancy-value muddle). Forty-six percent of the farmers had a positive intention to change their management in the next 5 years. The two behavioural constructs significantly related to this intention were attitude and social norm, whereas association with the perceived behavioural control construct was insignificant indicating that farmers did not perceive any barriers to change their behaviour. Relevant attitudinal beliefs indicated specific attributes of wheat, namely yield, quality and safety (lower mycotoxin contamination). This indicates that strengthening these beliefs—by demonstrating that a change in management will result in a higher yield and quality and lower mycotoxin levels—will result in a stronger attitude and, subsequently, a higher intention to change management. Interventions to strengthen these beliefs should preferably go by the most important referents for social norms, which were the buyers and the farmer cooperatives in this study.

Fungal Pathogens Affecting the Production and Quality of Medical Cannabis in Israel

The use of and research on medical cannabis (MC) is becoming more common, yet there are still many challenges regarding plant diseases of this crop. For example, there is a lack of formal and professional knowledge regarding fungi that infect MC plants, and practical and effective methods for managing the casual agents of disease are limited. The purpose of this study was to identify foliar, stem, and soilborne pathogens affecting MC under commercial cultivation in Israel. The predominant major foliage pathogens were identified as Alternaria alternata and Botrytis cinerea, while the common stem and soilborne pathogens were identified as Fusarium oxysporum and F. solani. Other important fungi that were isolated from foliage were those producing various mycotoxins that can directly harm patients, such as Aspergillus spp. and Penicillium spp. The sampling and characterization of potential pathogenic fungi were conducted from infected MC plant parts that exhibited various disease symptoms. Koch postulates were conducted by inoculating healthy MC tissues and intact plants with fungi isolated from infected commercially cultivated symptomatic plants. In this study, we report on the major and most common plant pathogens of MC found in Israel, and determine the seasonal outbreak of each fungus.

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.

Impact of the biofungicide tetramycin on the development of Fusarium head blight, grain yield and deoxynivalenol accumulation in wheat

Fusarium graminearum causes Fusarium head blight (FHB), a devastating disease that leads to extensive yield and quality loss in wheat and barley production. Integrated pest management (IPM) is required to control this disease and biofungicides, such as tetramycin, could be a novel addition to IPM strategies. The current study investigated in vitro tetramycin toxicity in Fusarium graminearum and evaluated its effectiveness for the control of Fusarium head blight FHB. Tetramycin was shown to affect three key aspects of Fusarium pathogenicity: spore germination, mycelium growth and deoxynivalenol (DON) production. The in vitro results indicated that tetramycin had strong inhibitory activity on the mycelial growth and spore germination. Field trials indicated that tetramycin treatment resulted in a significant reduction in both the FHB disease index and the level of DON accumulation. The reduced DON content in harvested grain was correlated with the amount of Tri5 mRNA determined by qRT-PCR. Synergistic effects between tetramycin and metconazole, in both the in vitro and field experiments were found. Tetramycin could provide an alternative option to control FHB.

Two small, cysteine-rich and cationic antifungal proteins from Penicillium chrysogenum: A comparative study of PAF and PAFB

The filamentous fungus Penicillium chrysogenum Q176 secretes the antimicrobial proteins (AMPs) PAF and PAFB, which share a compact disulfide-bond mediated, β-fold structure rendering them highly stable. These two AMPs effectively inhibit the growth of human pathogenic fungi in micromolar concentrations and exhibit antiviral potential without causing cytotoxic effects on mammalian cells in vitro and in vivo.

The antifungal mechanism of action of both AMPs is closely linked to - but not solely dependent on - the lipid composition of the fungal cell membrane and requires a strictly regulated protein uptake into the cell, indicating that PAF and PAFB are not canonical membrane active proteins. Variations in their antifungal spectrum and their killing dynamics point towards a divergent mode of action related to their physicochemical properties and surface charge distribution.

In this review, we relate characteristic features of PAF and PAFB to the current knowledge about other AMPs of different sources. In addition, we present original data that have never been published before to substantiate our assumptions and provide evidences that help to explain and understand better the mechanistic function of PAF and PAFB. Finally, we underline the promising potential of PAF and PAFB as future antifungal therapeutics.

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Penicillium chrysogenum secretes the small, cysteine-rich proteins PAF and PAFB.

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Both exhibit antifungal activity, but with differences in their mode of action.

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Structure, membrane interaction and cellular uptake determine their function.

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PAF and PAFB are well tolerated by mammalian cells.

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They promise applicability in medicine, plant protection and food industry.

Critical Assessment of Streptomyces spp. Able to Control Toxigenic Fusaria in Cereals: A Literature and Patent Review

Mycotoxins produced by Fusarium species on cereals represent a major concern for food safety worldwide. Fusarium toxins that are currently under regulation for their content in food include trichothecenes, fumonisins, and zearalenone. Biological control of Fusarium spp. has been widely explored with the aim of limiting disease occurrence, but few efforts have focused so far on limiting toxin accumulation in grains. The bacterial genus Streptomyces is responsible for the production of numerous drug molecules and represents a huge resource for the discovery of new molecules. Streptomyces spp. are also efficient plant colonizers and able to employ different mechanisms of control against toxigenic fungi on cereals. This review describes the outcomes of research using Streptomyces strains and/or their derived molecules to limit toxin production and/or contamination of Fusarium species in cereals. Both the scientific and patent literature were analyzed, starting from the year 2000, and we highlight promising results as well as the current pitfalls and limitations of this approach.

Influence of socio-economic and agronomic factors on aflatoxin and fumonisin contamination of maize in western Kenya

Consumption of maize contaminated with mycotoxins has been associated with detrimental health effects. A farm survey covering 116 push-pull and 139 non-push-pull cropping systems was conducted to determine the socio-economic and agronomic factors that influence farmers' knowledge on incidence and contamination of maize by ear rots and associated mycotoxins in western Kenya. All the respondents were smallholder farmers between the ages of 23 and 80 years, with 50% of them being female. Maize samples were collected from the standing crop in the field of each interviewed farmer and analyzed for aflatoxin and fumonisin. Only a small proportion of farmers had knowledge of aflatoxin and ear rots in maize. Overall, less than 20% of maize samples were contaminated with both aflatoxin and fumonisin, and more maize samples were contaminated with fumonisin as compared to aflatoxin. Proportions of maize samples containing higher than the acceptable Kenyan regulatory threshold (10 µg/kg) for aflatoxin and European Commission regulatory threshold (1,000) µg/kg for fumonisin were lower in maize samples from push-pull cropping system. Age of farmer and county of residence were significantly and positively associated with knowledge of aflatoxin, while cropping system, county of residence, and level of education were positively associated with knowledge of maize ear rots. There was strong correlation between knowledge of maize ear rots and knowledge of aflatoxin. Levels of both aflatoxin and fumonisin were significantly and positively associated with the use of diammonium phosphate (DAP) fertilizer at planting. Aflatoxin levels were also positively associated with stemborer damage. Agronomic practices were not significantly different between push-pull and non-push-pull farmers. However, use of DAP fertilizer was the most important agronomic factor since it was associated with both aflatoxin and fumonisin contamination of maize. These results imply that creating awareness is key to mitigation of ear rots and mycotoxin contamination of maize. The results also suggest that the levels of aflatoxin and fumonisin in maize in western Kenya were influenced both by pre-harvest agronomic practices and by the cropping system adopted, push-pull or not.

Effects of Atmospheric CO2 Level on the Metabolic Response of Resistant and Susceptible Wheat to Fusarium graminearum Infection

Rising atmospheric CO₂ concentrations and associated climate changes are thought to have contributed to the steady increase of Fusarium head blight (FHB) on wheat. However, our understanding of precisely how elevated CO₂ influences the defense response of wheat against Fusarium graminearum remains limited. In this study, we evaluated the metabolic profiles of susceptible (Norm) and moderately resistant (Alsen) spring wheat in response to whole-head inoculation with two deoxynivalenol (DON)-producing F. graminearum isolates (DON⁺), isolates 9F1 and Gz3639, and a DON-deficient (DON^-) isolate (Gzt40) at ambient (400 ppm) and elevated (800 ppm) CO₂ concentrations. The effects of elevated CO₂ were dependent on both the Fusarium strain and the wheat variety, but metabolic differences in the host can explain the observed changes in F. graminearum biomass and DON accumulation. The complexity of abiotic and biotic stress interactions makes it difficult to determine if the observed metabolic changes in wheat are a result of CO₂-induced changes in the host, the pathogen, or a combination of both. However, the effects of elevated CO₂ were not dependent on DON production. Finally, we identified several metabolic biomarkers for wheat that can reliably predict FHB resistance or susceptibility, even as atmospheric CO₂ levels rise.

Impact of fungicides and weather on cyclodepsipeptide-producing Fusarium spp. and beauvericin and enniatin levels in wheat grains

BACKGROUND

Fusarium head blight (FHB) is a well-known disease of wheat caused by a complex of Fusarium species. In this research, an extensive study on the occurrence of the emerging Fusarium cyclodepsipeptide mycotoxins beauvericin and enniatins was conducted in Belgian wheat grains harvested in 2015 and 2016. To assess the link between Fusarium species and their mycotoxin production, ultra-performance liquid chromatography-tandem mass spectrometry was used to quantify the cyclodepsipeptide mycotoxins, while quantitative polymerase chain reaction was applied to quantify the presence of Fusarium species.

RESULTS

It was shown that enniatins were mainly associated with the presence of F. avenaceum, while beauvericin, despite its low incidence, correlated significantly with F. poae. The application of fungicides resulted in a species shift and in the occurring mycotoxins. Concerning the effect of weather conditions, it was seen that levels of enniatins were positively correlated with the rainfall in May and June, while a negative correlation was observed with rainfall in the first half of July.

CONCLUSION

Our study provides new insights into the occurrence of the emerging cyclodepsipeptide mycotoxins in an agro-ecosystem in which fungicides are the main control measure against FHB. It seems that beauvericin and enniatin levels are affected by different parameters and behave differently upon application of fungicides. © 2018 Society of Chemical Industry.

The variation in hectolitre weight of wheat grain fed with or without enzyme supplementation influences nutrient digestibility and subsequently affects performance in pigs

A 2 × 2 factorial experiment was conducted to investigate the effect of feeding a wheat-based diet of two different hectolitre weights (66 vs. 74 kg/hl), achieved through different agronomical conditions, with or without the supplementation of a β-glucanase and β-xylanase enzyme mix on young pigs. The parameter categories which were assessed included growth performance, coefficient of apparent total tract digestibility (CATTD), faecal consistency, faecal microbial populations and faecal volatile fatty acid (VFA) concentrations. Sixty-four pigs (11.6 kg SD 0.97) were assigned to one of four dietary treatments: (T1) low hectolitre weight wheat diet, (T2) low hectolitre weight wheat diet containing 0.1 g/kg β-glucanase and β-xylanase enzyme supplement, (T3) high hectolitre weight wheat diet and (T4) high hectolitre weight wheat diet containing 0.1 g/kg β-glucanase and β-xylanase enzyme supplement. The inclusion of wheat was 500 g/kg in the diet. The low hectolitre weight grain had a higher level of zearalenone, aflatoxin and ochratoxin contamination compared to the high hectolitre weight grain. The high hectolitre weight wheat had a higher gross energy (GE), crude protein (CP) and lysine contents compared to the low hectolitre weight wheat. Pigs offered the low hectolitre weight diet had a lower average daily gain (ADG) (p < 0.001), a lower gain to feed (G:F) ratio (p < 0.001) and a higher faecal score (more diarrhoea) (p < 0.001) compared to pigs offered the high hectolitre weight. The low hectolitre weight diet had a reduced CATTD (p < 0.05) of nitrogen (N) and gross energy (GE) compared with pigs offered the high hectolitre weight diet. In conclusion, the higher level of mycotoxins and lower content of GE, CP and lysine in the low-quality wheat reduced ADG and the CATTD of nutrients in pigs offered this diet. The inclusion of a β-glucanase and β-xylanase enzyme mix had no effect on growth performance or nutrient digestibility.

Silage review: Mycotoxins in silage: Occurrence, effects, prevention, and mitigation

Ensiled forage, particularly corn silage, is an important component of dairy cow diets worldwide. Forages can be contaminated with several mycotoxins in the field pre-harvest, during storage, or after ensiling during feed-out. Exposure to dietary mycotoxins adversely affects the performance and health of livestock and can compromise human health. Several studies and surveys indicate that ruminants are often exposed to mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins, zearalenone, and many other fungal secondary metabolites, via the silage they ingest. Problems associated with mycotoxins in silage can be minimized by preventing fungal growth before and after ensiling. Proper silage management is essential to reduce mycotoxin contamination of dairy cow feeds, and certain mold-inhibiting chemical additives or microbial inoculants can also reduce the contamination levels. Several sequestering agents also can be added to diets to reduce mycotoxin levels, but their efficacy varies with the type and level of mycotoxin contamination. This article gives an overview of the types, prevalence, and levels of mycotoxin contamination in ensiled forages in different countries, and describes their adverse effects on health of ruminants, and effective prevention and mitigation strategies for dairy cow diets. Future research priorities discussed include research efforts to develop silage additives or rumen microbial innocula that degrade mycotoxins.

Nanoparticles as a Solution for Eliminating the Risk of Mycotoxins

Mycotoxins are toxic secondary metabolites produced by certain filamentous fungi. The occurrence of mycotoxins in food and feed causes negative health impacts on both humans and animals. Clay binders, yeast cell walls, or antioxidant additives are the most widely used products for mycotoxin elimination to reduce their impact. Although conventional methods are constantly improving, current research trends are looking for innovative solutions. Nanotechnology approaches seem to be a promising, effective, and low-cost way to minimize the health effects of mycotoxins. This review aims to shed light on the critical knowledge gap in mycotoxin elimination by nanotechnology. There are three main strategies: mold inhibition, mycotoxin adsorption, and reducing the toxic effect via nanoparticles. One of the most promising methods is the use of carbon-based nanomaterials. Graphene has been shown to have a huge surface and high binding capacity for mycotoxins. Attention has also been drawn to polymeric nanoparticles; they could substitute adsorbents or enclose any substance, which would improve the health status of the organism. In light of these findings, this review gives new insights into possible future research that might overcome challenges associated with nanotechnology utilization for mycotoxin elimination from agricultural products.

Canopy and Ear Traits Associated With Avoidance of Fusarium Head Blight in Wheat

Doubled haploid and elite wheat genotypes were ground inoculated in three field experiments and head spray inoculated in two glasshouse experiments, using mixed Fusarium and Microdochium species, to identify crop canopy and ear traits associated with Fusarium head blight (FHB) disease. In all experiments, flag leaf length and tiller number were consistently identified as the most significant canopy traits contributing to progression of FHB caused by Fusarium graminearum, F. culmorum, and F. avenaceum. The influence of ear traits was greater for F. poae that may possess more diverse routes for transmission and spread. Consistently, spikelet density was associated with increased disease severity in the field. F. graminearum, F. culmorum, and F. langsethiae were the main mycotoxin producers and their respective toxins were significantly related to fungal biomass and number of spikelets per ear. Genotypes with lower tiller numbers, shorter flag leaves and less dense ears may be able to avoid FHB disease caused by F. graminearum, F. culmorum, F. avenaceum, or Microdochium species however selection for these canopy and ear architectural traits to enable disease avoidance in wheat is likely to result in a potential trade-off with grain yield and therefore only moderately advantageous in susceptible genotypes.

Biosynthesis of Low Molecular Weight Antifungal Protein from Aspergillus giganteus in Batch Fermentation and In-Vitro Assay

　In present study, Taguchi's design of experiment L₉ orthogonal array was created using Qualitek-4 software with four most critical factors namely, K₂HPO₄, MgSO₄, CaCl₂ and culture pH. Production of a new intracellular antifungal protein in submerged fermentation was optimized with yield of 0.98±0.1 mg/gram dry cell weight mycelia from Aspergillus giganteus MTCC 8408. The average molecular mass of the purified protein was figured as 5.122 kDa using Electro Spray Ionization-Mass Spectrometry. Scanning electron microscopy was used to correlate the effect of selected factors on fungal cell morphology and its metabolite production. In vitro antifungal susceptibility assay was profiled against Aspergillus niger and minimum inhibitory concentrations were in the range 0.3±0.06 µg/ml. The stronger influencing factors on afp production and mycelial biomass were noted with CaCl₂ and K₂HPO₄ respectively. The validation experiments using optimized conditions confirmed an improvement in afp by 3.86 times with mycelial biomass by 1.52 times, compared to the basal medium. The present statistical optimization study revealed an opportunity to promote economical design at the industrial level for future scale up of effective antifungal agent against systemic aspergillosis as well as possible post harvest loss.

Selective effect of myclobutanil enantiomers on fungicidal activity and fumonisin production by Fusarium verticillioides under different environmental conditions

Myclobutanil is a widely used triazole fungicide, comprising two enantiomers with different fungicidal activities, non-target toxicities, and environmental fates. The enantioselective effects of myclobutanil on fumonisin B (FB) production by Fusarium verticillioides, an important pathogen, have not yet been investigated. In the present study, the fungicidal activities of rac-myclobutanil and its enantiomers on F. verticillioides cultured on maize-based media were studied under different water activity and temperature conditions. The FB levels were measured to assess the enantioselective effects on FB production when F. verticillioides were cultured treated with EC₅₀ and EC₉₀ concentrations (concentrations inhibiting mycelial growth by 50.0% and 90.0%, respectively) of myclobutanil and enantiomers under different conditions. The fungicidal activities of rac-myclobutanil and its enantiomers decreased with increasing temperature and decreasing water activity. Little difference in fungicidal activity was observed between the enantiomers. FB production was significantly influenced by temperature, a_w, and fungicides dose. At EC50 concentrations, rac-myclobutantil and its enantiomers were shown to enhance mycotoxin production and enantioselective effects of enantiomers on FB production were observed under certain conditions. This is the first report on the differential effects of myclobutanil enantiomers on the control of F. verticillioides growth and FB production in maize-based media under different conditions.

Community Profiling of Fusarium in Combination with Other Plant-Associated Fungi in Different Crop Species Using SMRT Sequencing

Fusarium head blight, caused by fungi from the genus Fusarium, is one of the most harmful cereal diseases, resulting not only in severe yield losses but also in mycotoxin contaminated and health-threatening grains. Fusarium head blight is caused by a diverse set of species that have different host ranges, mycotoxin profiles and responses to agricultural practices. Thus, understanding the composition of Fusarium communities in the field is crucial for estimating their impact and also for the development of effective control measures. Up to now, most molecular tools that monitor Fusarium communities on plants are limited to certain species and do not distinguish other plant associated fungi. To close these gaps, we developed a sequencing-based community profiling methodology for crop-associated fungi with a focus on the genus Fusarium. By analyzing a 1600 bp long amplicon spanning the highly variable segments ITS and D1-D3 of the ribosomal operon by PacBio SMRT sequencing, we were able to robustly quantify Fusarium down to species level through clustering against reference sequences. The newly developed methodology was successfully validated in mock communities and provided similar results as the culture-based assessment of Fusarium communities by seed health tests in grain samples from different crop species. Finally, we exemplified the newly developed methodology in a field experiment with a wheat-maize crop sequence under different cover crop and tillage regimes. We analyzed wheat straw residues, cover crop shoots and maize grains and we could reveal that the cover crop hairy vetch (Vicia villosa) acts as a potent alternative host for Fusarium (OTU F.ave/tri) showing an eightfold higher relative abundance compared with other cover crop treatments. Moreover, as the newly developed methodology also allows to trace other crop-associated fungi, we found that vetch and green fallow hosted further fungal plant pathogens including Zymoseptoria tritici. Thus, besides their beneficial traits, cover crops can also entail phytopathological risks by acting as alternative hosts for Fusarium and other noxious plant pathogens. The newly developed sequencing based methodology is a powerful diagnostic tool to trace Fusarium in combination with other fungi associated to different crop species.

Impact of agronomic and climatic factors on the mycotoxin content of harvested oats in the United Kingdom

A survey was conducted to determine the concentration of Fusarium mycotoxins in UK oats over three seasons (2006-8). One hundred oat samples were collected each year at harvest, together with agronomic details, and analysed for 10 Fusarium mycotoxins. The incidence and concentration of most Fusarium mycotoxins, including deoxynivalenol and zearalenone, were relatively low in oats compared with values previously reported for wheat. HT-2 toxin (HT2) and T-2 toxin (T2) levels were relatively high with an overall combined (HT2+T2) mean of 450 μg kg^-1 for 2006-8. Data were combined with a previous dataset collected from 2002-5 to determine the effects of agronomic practices and climate. There was a negative relationship with late summer rainfall, indicating that drier conditions in July and August resulted in increased HT2 and T2 in UK oats. Agronomic factors that impacted upon HT2 and T2 in harvested oats were previous crop, cultivation, and variety. Analysis of the previous cropping history showed there was a stepwise increase in HT2+T2 as the cereal intensity of the rotation increased. Variety was an important factor, with higher levels and a wider range detected on winter versus spring varieties. Indicative levels for HT2 and T2 in cereals and cereal products were introduced by the EC in 2013. The indicative level for unprocessed oats for human consumption is a combined concentration (HT2+T2) of 1000 μg kg^-1. From 2002 to 2008, between 1% and 30% of samples exceeded 1000 μg kg^-1 HT2+T2 each year (overall mean, 16%). The introduction of European legislation on HT2 and T2 mycotoxins could have serious implications for UK oat production and oat-processing industries based on the levels detected within these studies.

Optimization and partial characterization of intracellular anticandidal protein from Aspergillus giganteus MTCC 8408 using taguchi DOE

A new intracellular antifungal protein (afp) production with average molecular weight 24.3 kDa and yield of 0.65 ± 0.1 mg/gram dry cell weight (gdcw) of mycelia in submerged fermentation of Aspergillus giganteus MTCC 8408 was optimized. Taguchi's DOE (design of experiment) L₂₇ orthogonal array (OA) was constructed using Qualitek-4 software with 8 most influensive factors namely, culture pH, temperature, slant age, inoculum volume, agitation and KH₂PO₄. Scanning electron microscopy (SEM) was used to correlate the effect of selected factors on fungal cell morphology and afp production. The crude protein purification was accomplished using pure ammonium sulfate fractionation followed by carboxymethyl cellulose (CMC) ion-exchange chromatography and sephadex G-100 gel filtration. The average molecular mass of the purified protein was figured by silver stained SDS (sodium dodecylsulphate)-PAGE (poly-acryl amide gel electrophoresis). In vitro antifungal susceptibility assay was profiled against Candida albicans NCIM 3471 and minimum inhibitory concentrations (MICs) were in the range 3 to 4 µg/ml. Characterization of protein was observed with FTIR (Fourier transform infrared spectroscopy) analysis. The optimal production condition for crude afp was obtained as follows: soluble starch: 20 g/l; Corn steep liquor (CSL, 2%) + proteose peptone (PP, 1%): 30 g/l; pH: 5.8; temperature: 25°C; slant age: 3 d; inoculum size: 5% (v/v); agitation: 180 rpm; KH₂PO₄: 0.1 g/l. The validation experiments using optimized conditions confirmed an improvement in afp production by 59.4% against the expected enhancement of afp production by 61.22%. The present statistical optimization study revealed an opportunity to promote economical design at the industrial level for future scale up of effective antifungal agent against opportunistic oral and vaginal infection.

Database of resistance related metabolites in Wheat Fusarium head blight Disease (MWFD)

Fungal diseases are an increasing threat to worldwide food security. Fusarium head blight (FHB), primarily caused by Fusarium graminearum, is a devastating disease of Triticum aestivum (bread wheat). Partial resistance to FHB of several wheat and barley cultivars includes specific metabolic responses to inoculation. Investigation of metabolic changes in plants, following pathogen infection, provides valuable data for understanding of the role of metabolites and metabolism in plant-pathogen interaction and resistance. Determination of functions of metabolites in resistance can also inspire the development of antifungals. Metabolic changes induced by FHB in resistant and susceptible plants have been previously investigated. However, the functionality of the majority of these investigated metabolites remains unknown. The ‘Metabolites in the Wheat Fusarium head blight Disease’ (MWFD) database was compiled in order to determine possible targets and roles of these molecules in resistance to FBH and aid in the development of related synthetic antifungals. The MWFD database allows for the quick retrieval of known resistance related metabolites, associated target proteins and their sequence analogues in wheat and Fusarium genomes. The database can be searched for compounds, MeSH terms, as well as protein targets. This comprehensive, manually curated, collection of resistance related metabolites is available at https://bioinfo.nrc.ca/mwfd/index.php.

Database URL:https://bioinfo.nrc.ca/mwfd/index.php

Growth Inhibition and Morphological Alteration of Fusarium sporotrichioides by Mentha piperita Essential Oil

OBJECTIVE

The aim of this study is to determine the phytochemical composition, antifungal activity of Mentha piperita essential oil (MPE) against Fusarium sporotrichioides.

METHODS

The phytochemical composition was conducted by gas chromatography mass spectrometry (GC MS) analysis and mycelia growth inhibition was determined by minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC), the morphological characterization was observed by scanning electron microscopy. Finally, the membrane permeability was determined by the release of extracellular constituents, pH, and total lipid content.

RESULT

In GC MS analysis, 22 metabolites were identified such as menthol, l menthone, pulegone, piperitone, caryophyllene, menthol acetate, etc. The antifungal activity against targeted pathogen, with MIC and MFC 500 μg/mL and 1000 μg/mL, respectively. The MPE altered the morphology of F. sporotrichoides hyphae with the loss of cytoplasm content and contorted the mycelia. The increasing concentration of MPE showed increase in membrane permeability of F. sporotrichoides as evidenced by the release of extracellular constituents and pH with the disruption of cell membrane indicating decrease in lipid content of F. sporotrichoides.

CONCLUSION

The observed results showed that MPE exhibited promising new antifungal agent against Fusarium sporotrichioides.

SUMMARY

F. sporotrichioides, filamentous fungi contaminate to corn and corn--based productsF. sporotrichioides mainly responsible for the production of T-2 toxinPhytochemical composition was conducted by gas chromatography--mass spectrometry analysisMentha piperita essential oil (MPE) is commonly known as peppermintThe F. sporotrichioides growth was inhibited by MPE (minimum inhibitory concentration, minimum fungicidal concentration)Morphological observation by scanning electron microscope. Abbreviations Used: Cfu: Colony forming unit; DMSO: Dimethyl sulfoxide, °C: Degree celsius; F. Sporotrichoides: Fusarium sporotrichioides; EOs: Essential oils; M: Molar, g: Gram/gravity, mg: Milligram; μg: Microgram, ml: Milliliter; mm: Millimeter, min: Minutes; M. piperita: Mentha piperita, MIC: Minimum inhibitory concentration; MFC: Minimum fungicidal concentration; MAE: Mentha arvensis essential oil; Na2SO4: Sodium sulfate; pH: Potential Hydrogen; PDB: Potato Dextrose Broth; SEM: Scanning electron microscope.