Nivalenol Research Articles

A Novel SERS Label-Free Sensing Strategy for DON and NIV: A DFT Study on the Interaction between DON/NIV and Ag/Au.

In this study, we propose a novel label-free detection strategy based on surface-enhanced Raman spectroscopy (SERS) for detecting deoxynivalenol (DON) and nivalenol (NIV), analyzing the interactions between these fungal toxins and Ag/Au substrates using density functional theory (DFT). The DFT calculation results indicate that the oxygen atoms in DON and NIV molecules exhibit high electronegativity, suggesting that they can serve as active sites in interaction with the metal surfaces in the SERS effect. By constructing DON/NIV-Ag6/Au6 complex models and evaluating their binding energies, we demonstrate the formation of stable complexes, showing characteristic frequency shifts, broadening, and selective enhancement in theoretical Raman spectra. The results indicate that the structural differences between DON and NIV lead to significant variations in the characteristic frequencies of their theoretical SERS spectra, providing a reproducible and interference-resistant method for the label-free detection of these fungal toxins. This work enhances the understanding of molecular-substrate interactions in SERS effects and provides a theoretical basis for the application of label-free SERS sensing strategies based on characteristic frequency shifts.

Identification and Differentiation of the Fusarium graminearum NX-2 Chemotype Using High-Resolution Melting (HRM).

Fusarium head blight causes significant yield losses in wheat and other cereals and contaminates grain products with trichothecene mycotoxins. F. graminearum isolates are classified into different chemotypes depending on the type of mycotoxin produced, including the type B trichothecenes 3-acetyl deoxynivalenol (3-ADON), 15-acetyl deoxynivalenol (15-ADON), nivalenol (NIV), and the recently identified type A trichothecene NX-2. Molecular tools to differentiate NX-2 producers from other chemotypes have remained relatively laborious and time consuming. In this study, we developed and validated a high-resolution melting (HRM) assay that can identify NX-2 producers quickly and cost-effectively. By analyzing TRI1 coding sequences from 183 geographically diverse isolates representing all four F. graminearum chemotypes, we selected a 75-base pair region containing four non-synonymous single nucleotide polymorphisms (SNPs) that are specific to the NX-2 genotypes. The amplicon generated two HRM profiles, one of which was specific for only NX-2. We confirmed that the assay is robust across qPCR platforms and unambiguously differentiates NX-2 from other chemotypes using a panel of 72 diverse isolates previously collected from North America. The HRM assay was also successful in identifying NX-2 producers directly from DNA extracted from infected wheat spikes with varying levels of disease severity and fungal DNA. The assay can detect as little as 0.01 ng of fungal DNA in a background of 50 ng of plant DNA. This new diagnostic assay can be used for high-throughput molecular detection of the NX-2 chemotype of F. graminearum from infected plant samples and culture collections, thus making it a valuable tool for surveys of contemporary and historical FHB pathogen populations.

Development of a high-throughput UHPLC-MS/MS method for the analysis of Fusarium and Alternaria toxins in cereals and cereal-based food.

A QuEChERS (quick, easy, cheap, effective, rugged, and safe)-based multi-mycotoxin method was developed, analyzing 24 (17 free and 7 modified) Alternaria and Fusarium toxins in cereals via ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). A modified QuEChERS approach was optimized for sample preparation. Quantification was conducted using a combination of stable isotope dilution analysis (SIDA) for nine toxins and matrix-matched calibration for ten toxins. Quantification via a structurally similar internal standard was conducted for four analytes. Alternariol-9-sulfate (AOH-9-S) was measured qualitatively. Limits of detection (LODs) were between 0.004µg/kg for enniatin A1 (ENN A1) and 3.16µg/kg for nivalenol (NIV), while the limits of quantification were between 0.013 and 11.8µg/kg, respectively. The method was successfully applied to analyze 136 cereals and cereal-based foods, including 28 cereal-based infant food products. The analyzed samples were frequently contaminated with Alternaria toxins, proving their ubiquitous occurrence. Interestingly, in many of those samples, some modified Alternaria toxins occurred, mainly alternariol-3-sulfate (AOH-3-S) and alternariol monomethyl ether-3-sulfate (AME-3-S), thus highlighting the importance of including modified mycotoxins in the routine analysis as they may significantly add to the total exposure of their parent toxins. Over 95% of the analyzed samples were contaminated with at least one toxin. Despite the general contamination, no maximum or indicative levels were exceeded.

Frequent Dietary Multi-Mycotoxin Exposure in UK Children and Its Association with Dietary Intake.

Mycotoxins are potent fungal toxins that frequently contaminate agricultural crops and foods. Mycotoxin exposure is frequently reported in humans, and children are known to be particularly at risk of exceeding safe levels of exposure. Urinary biomonitoring is used to assess overall dietary exposure to multiple mycotoxins. This study aims to quantify multi-mycotoxin exposure in UK children and to identify major food groups contributing to exposure. Four repeat urine samples were collected from 29 children (13 boys and 16 girls, aged 2.4-6.8 years), and food diaries were recorded to assess their exposure to eleven mycotoxins. Urine samples (n = 114) were hydrolysed with β-glucuronidase, enriched through immunoaffinity columns and analysed by LC-MS/MS for deoxynivalenol (DON), nivalenol (NIV), T-2/HT-2 toxins, zearalenone (ZEN), ochratoxin A (OTA) and aflatoxins. Food diaries were analysed using WinDiet software, and the daily intake of high-risk foods for mycotoxin contamination summarised. The most prevalent mycotoxins found in urine samples were DON (95.6% of all samples), OTA (88.6%), HT-2 toxin (53.5%), ZEN (48.2%) and NIV (26.3%). Intake of total cereal-based foods was strongly positively associated with urinary levels of DON and T-2/HT-2 and oat intake with urinary T-2/HT-2. Average daily mycotoxin excretion ranged from 12.10 µg/d (DON) to 0.03 µg/d (OTA), and co-exposure to three or more mycotoxins was found in 66% of samples. Comparing mycotoxin intake estimates to tolerable daily intakes (TDI) demonstrates frequent TDI exceedances (DON 34.2% of all samples, T-2/HT-2 14.9%, NIV 4.4% and ZEN 5.2%). OTA was frequently detected at low levels. When mean daily OTA intake was compared to the reference value for non-neoplastic lesions, the resulting Margin of Exposure (MoE) of 65 was narrow, indicating a health concern. In conclusion, this study demonstrates frequent exposure of UK children to multiple mycotoxins at levels high enough to pose a health concern if exposure is continuous.

Genetic Diversity, Mycotoxin Profiles, and Population Structure of Fusarium spp. Associated with Fusarium Head Blight in Georgia, United States.

Fusarium head blight (FHB) has become a limiting factor in soft red winter wheat production in the southeast United States. Recent epidemics have occurred in Georgia, but genetic information on the Fusarium species responsible for FHB is unknown. This study aimed to assess pathogen population structure and genetic diversity, trichothecene profiles, and representative pathogenicity of 196 Fusarium isolates collected from 44 wheat (n = 85) and 53 corn (n = 111) fields in Georgia. Phylogenetic analysis using the translation elongation factor 1-alpha (635 bp) and RNA polymerase second largest subunit (930 bp) sequence data resolved isolates into 185 haplotypes, which represented 12 Fusarium species grouped under five species complexes. F. graminearum with 15-acetyl-deoxynivalenol (15ADON) chemotype (75.6%) and F. incarnatum (57.7%) predominated in wheat and corn, respectively, with a surprisingly higher frequency of nivalenol (NIV) F. graminearum (21.8%). Using nine variable numbers of tandem repeat markers, 82 multilocus genotypes out of 86 F. graminearum isolates were identified and grouped into two genetic clusters, pop1fg (n = 29) and pop2fg (n = 32), as part of the North American populations (NA1 and NA2) but with no chemotype differentiation. F. graminearum populations in Georgia are mostly clonal and might have evolved through at least two introductions from the northeast United States and Canada and local adaptation to maintain high genetic diversity. Pathogenicity of F. graminearum isolates from wheat and corn had high FHB severity (>60%) in wheat, which depicted the risk they can pose towards future FHB outbreaks. Overall, this baseline study provided important information on Fusarium species diversity including F. graminearum associated with FHB in Georgia that will be useful to formulate integrated disease management incorporating improved host resistance and fungicide spray programs.

Characterization of Fusarium species causing head blight of highland barley (qingke) in Tibet, China

Most of the research on the characterization of Fusarium species focused on wheat, barley, rice, and maize in China. However, there has been limited research in highland barley (qingke). Recently, Fusarium head blight (FHB) of qingke was recently observed in Tibet, China, especially around the Brahmaputra River. To gain a better understanding of the pathogens involver, 201 Fusarium isolates were obtained from qingke samples in 2020. Among these isolates, the most abundant species was F. avenaceum (45.3 %), followed by F. equiseti (27.8 %), F. verticillioides (13.9 %), F. acuminatum (9.0 %), F. flocciferum (3.5 %), and F. proliferatum (0.5 %). The distribution of Fusarium species varied along the Brahmaputra River, with F. avenaceum being predominant in the midstream and downstream regions, while F. equiseti was more common in the upstream region. Chemical analyses of all the isolates revealed the production of different mycotoxins by various Fusarium species. It was found that enniatins were produced by F. acuminatum, F. avenaceum, and F. flocciferum, beauvericin (BEA) and fumonisins were produced F. proliferatum and F. verticillioides, and zearalenone (ZEN) and nivalenol (NIV) were produced by F. equiseti. Pathogenicity test showed that F. avenaceum was more aggressive in causing FHB compared to F. acuminatum, F. equiseti, and F. flocciferum. The disease severity, measured by the area under the disease progress curve (AUDPC), was significantly positively (P < 0.01) correlated with the concentration of total toxins produced by each species. Furthermore, all the Fusarium strains which were used for pathogenicity test were susceptible to carbendazim, and the 50 % effective concentration (EC50) ranged from 0.406 μg/mL to 0.673 μg/mL with an average EC50 of 0.551 ± 0.012 μg/mL.

Sub-acute oral exposure to lowest observed adverse effect level of nivalenol exacerbates atopic dermatitis in mice via direct activation of mitogen-activated protein kinase signal in antigen-presenting cells.

This study investigated the immunotoxic effects of the mycotoxin nivalenol (NIV) using antigen-presenting cells and a mouse model of atopic dermatitis (AD). In vitro experiments were conducted using a mouse macrophage cell line (RAW 264.7) and mouse dendritic cell line (DC 2.4). After cells were exposed to NIV (0.19-5µmol) for 24h, the production of pro-inflammatory cytokines (IL-1β, IL-6, and TNFα) was quantified. To further investigate the inflammatory cytokine production pathway, the possible involvement of mitogen-activated protein kinase (MAPK) pathways, such as ERK1/2, p-38, and JNK, in NIV exposure was analyzed using MAPK inhibitors and phosphorylation analyses. In addition, the pro-inflammatory effects of oral exposure to NIV at low concentrations (1 or 5ppm) were evaluated in an NC/Nga mouse model of hapten-induced AD. In vitro experiments demonstrated that exposure to NIV significantly enhanced the production of TNFα. In addition, it also directly induced the phosphorylation of MAPK, indicated by the inhibition of TNFα production following pretreatment with MAPK inhibitors. Oral exposure to NIV significantly exacerbated the symptoms of AD, including a significant increase in helper T cells and IgE-produced B cells in auricular lymph nodes and secretion of pro-inflammatory cytokines, such as IL-4, IL-5, and IL-13, compared with the vehicle control group. Our findings indicate that exposure to NIV directly enhanced the phosphorylation of ERK1/2, p-38, and JNK, resulting in a significant increase in TNFα production in antigen-presenting cells, which is closely related to the development of atopic dermatitis.

Fabrication of polydopamine functionalized AgNF SERS substrate: Applications for sensitive detection of nivalenol in food samples and cell biocompatibility

Surface-enhanced Raman spectroscopy (SERS) is a robust analytical tool applicable for the quick and accurate determination of mycotoxins. However, there hasn't been any attempt to use SERS for the quantitative detection of nivalenol (NIV) thus far. To improve the Raman signals of NIV, we fabricated a polydopamine-coated silver nanoflower (PDA-AgNFs) SERS substrate with strong “hot-spots”. The PDA-AgNFs substrates showed superior SERS enhancement activities in the target analyte detection and quantification. It produced good substrate uniformity (relative standard deviation of SERS signals, RSD = 4.1% for substrate-to-substrate test, and 3.24% for spot-to-spot test), an enhancement factor of 2.87 × 106 towards rhodamine 6B (R6G), and detection sensitivity as low as 1 femtomolar (10−15 M) against R6G probe molecule. Moreover, the PDA-AgNFs SERS substrates were successfully used, for the first time, to detect NIV in corn, horse beans, and mushroom samples. The calibration curve showed a satisfactory linear fit based on the SERS intensities of different NIV concentrations. The detection limit (LOD) for the suggested approach was 0.22 nM (S/N = 3). Interestingly, the MTT assay experiment demonstrated that PDA-AgNFs had no toxicity against mammalian NIH-3T3 cells. The biocompatible PDA-AgNFs substrates with intense plasmonic effects and binding sites demonstrated impressive Raman enhancement, and could serve as an effective, label-free, and fast SERS-based analysis of NIV in real samples.

Endophytic Alternaria and Fusarium species associated to potato plants (Solanum tuberosum L.) in Iran and their capability to produce regulated and emerging mycotoxins

Endophytic fungi live inside virtually every plant species, without causing any apparent disease or damage to the host. Nevertheless, under particular conditions, mutualistic lifestyle of endophytes may change to pathogenic. In this study, the biodiversity of Alternaria and Fusarium species, the two most abundant endophytic fungi isolated from healthy potato plants in two climatically different regions of Iran, Ardebil in the north-west and Kerman in the south-east, was investigated. Seventy-five Fusarium strains and 83 Alternaria strains were molecularly characterized by multi-locus gene sequencing. Alternaria strains were characterized by the sequences of gpd and caM gene fragments and the phylogenetic tree was resolved in 3 well-separated clades. Seventy-three strains were included in the clade A, referred as Alternaria section, 6 strains were included in clade B, referred as Ulocladioides section, and 4 strains were included in clade C, referred as Infectoriae section. Fusarium strains, identified by sequencing the translation elongation factor 1α (tef1), β-tubulin (tub2) and internal transcribed spacer (ITS) genomic regions, were assigned to 13 species, viz. F. brachygibosum, F. clavum, F. equiseti, F. flocciferum, F. incarnatum, F. nirenbergiae, F. nygamai, F. oxysporum, F. proliferatum, F. redolens, F. sambucinum, F. solani and F. thapsinum. Twenty-six selected strains, representative of F. equiseti, F. nirenbergiae, F. oxysporum, F. nygamai, F. proliferatum, and F. sambucinum, were also tested for production of the mycotoxins deoxynivalenol (DON), nivalenol (NIV), diacetoxyscirpenol (DAS), T-2 toxin (T-2), beauvericin (BEA), enniatins (ENNs), fumonisins (FBs), fusaric acid (FA) and moniliformin (MON). None of the tested strains produced trichothecene toxins (DON, NIV, DAS and T-2). Two out of 2 F. equiseti isolates, 1/6 F. oxysporum, 1/3 F. proliferatum, and 1/9 F. nygamai did not produce any of the tested toxins; the rest of strains produced one or more BEA, ENNs, FBs, FA and MON toxins. The most toxigenic strain, F. nygamai ITEM-19012, produced the highest quantities of FBs (7946, 4693 and 4333 μg/g of B1, B2, and B3 respectively), along with the highest quantities of both BEA (4190 μg/g) and MON (538 μg/g). These findings suggest that contamination of potato tubers with mycotoxins in the field or at post-harvest, due to a change in lifestyle of endophytic microflora, should be carefully considered and furtherly investigated.

Bacillus velezensis RC218 and emerging biocontrol agents against Fusarium graminearum and Fusarium poae in barley: in vitro, greenhouse and field conditions

Fusarium head blight (FHB) is one of the most common diseases in Argentina, affecting the quality and yield of barley grains. Fusarium graminearum sensu stricto (ss) and Fusarium poae are causal agents of FHB and potential sources of mycotoxin contamination in barley. Conventional management strategies do not lead to a complete control of FHB; therefore, biological control emerges as an eco-friendly alternative in the integrated management of the disease. In the present work, Bacillus velezensis, Bacillus inaquosorum, Bacillus nakamurai and Lactobacillus plantarum were evaluated as potential biocontrol agents against F. graminearum ss and F. poae on barley-based media. Bacillus velezensis RC218 was selected to carry out greenhouse and field trials in order to reduce FHB and mycotoxin accumulation. This strain was able to control growth of both Fusarium species and reduced deoxynivalenol (DON) and nivalenol (NIV) production by 66 % and 79 %, respectively. Bacillus inaquosorum and B. nakamurai were more effective in controlling F. poae growth, and the mean levels of reduction in DON accumulation were 50 and 38 %, and 93 and 26 % for NIV, respectively. Lactobacillus plantarum showed variable biocontrol capacity depending on the strain, with no significant mycotoxin reduction. The biocontrol on incidence and severity of FHB in the greenhouse and field trials was effective, being more efficient against F. graminearum ss and DON accumulation than against F. poae and NIV occurrence. This study provides valuable data for the development of an efficient tool based on biocontrol agents to prevent FHB-producing Fusarium species development and mycotoxin occurrence in barley, contributing to food safety.

A Study of a New Certified Reference Material for Accurate Determination of the Main Fusarium Mycotoxins in Whole-Wheat Flour.

Matrix certified reference materials (CRMs) play a critical role in analytical method validation and the assurance of reliable measurement results. A certified reference material (GBW(E)100813) for whole-wheat flour was developed to ensure an accurate and reliable measurement of the main Fusarium mycotoxins (deoxynivalenol (DON), nivalenol (NIV), deoxynivalenol-3-glucoside (DON-3G), and zearalenone (ZEN)). CRM candidates were prepared using sun-drying, grinding, sieving, homogenising, packaging, and gamma irradiation. The final produced CRM was packaged at 50 g per unit and stored at 20 °C. Certification was performed using isotope dilution-liquid chromatography-tandem mass spectrometry. CRM characterization was performed in eight laboratories in accordance with the requirements of ISO Guide 35. The certified values and expanded uncertainties (at a confidence of 95%, k = 2) for DON, NIV, DON-3G, and ZEN were determined to be 0.98 ± 0.12 mg/kg, 1.37 ± 0.20 mg/kg, 242 ± 35 μg/g, and 382 ± 50 μg/g. The CRM was sufficiently homogeneous between and within bottles, and remained stable for up to 12 months at 20 °C and 9 days below 40 °C for transportation. Thus, CRM can be used for quality control and method validation to ensure the accurate and reliable quantification of the main Fusarium mycotoxins in whole-wheat flour.

Genome Sequence Resource of the Head Blight Pathogens Fusarium asiaticum and F. graminearum Isolated from Cereal Crops and Gramineous Weeds in Korea and China

Head blight is a serious fungal disease that results in yield loss and mycotoxin contamination in cereal crops worldwide. Head blight is primarily caused by members of the Fusarium graminearum species complex (FGSC), which consists of at least 16 species, including Fusarium asiaticum and Fusarium graminearum. FGSC members produce trichothecene mycotoxins and can be divided into four groups (chemotypes) depending on the type of trichothecenes produced: NIV (production of nivalenol), 3ADON (production of 3-acetyldeoxynivalenol), 15ADON (production of 15-acetyldeoxynivalenol), and NX-2 (production of 3α-acetoxy, 7α, 15-dihydroxy-12, and 13-epoxytrichothe-9-ene). Whereas F. graminearum mainly causes head blight in wheat-producing areas, F. asiaticum is associated primarily with rice head blight in eastern Asia. To date, the NCBI database archives 116 assembled genome sequences of F. graminearum, but only four accessions correspond to F. asiaticum. Accessions for three F. graminearum strains (PH-1 = NRRL 31084, CS3005, and FG-12) are chromosome assemblies (i.e., include contigs/scaffolds consisting of full-length or nearly full-length chromosomes), but none of the F. asiaticum accessions is a chromosome assembly. This announcement reports the assembled genome sequences of nine F. asiaticum strains and seven F. graminearum strains isolated from rice, wheat, barley, and other gramineous plants in Korea and China. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

The Role of Mycotoxins in Interactions between Fusarium graminearum and F. verticillioides Growing in Saprophytic Cultures and Co-Infecting Maize Plants.

Fusarium graminearum (FG) and Fusarium verticillioides (FV) co-occur in infected plants and plant residues. In maize ears, the growth of FV is stimulated while FG is suppressed. To elucidate the role of mycotoxins in these effects, we used FG mutants with disrupted synthesis of nivalenol (NIV) and deoxynivalenol (DON) and a FV mutant with disrupted synthesis of fumonisins to monitor fungal growth in mixed cultures in vitro and in co-infected plants by real-time PCR. In autoclaved grains as well as in maize ears, the growth of FV was stimulated by FG regardless of the production of DON or NIV by the latter, whereas the growth of FG was suppressed. In autoclaved grains, fumonisin-producing FV suppressed FG more strongly than a fumonisin-nonproducing strain, indicating that fumonisins act as interference competition agents. In co-infected maize ears, FG suppression was independent of fumonisin production by FV, likely due to heterogeneous infection and a lower level of fumonisins in planta. We conclude that (i) fumonisins are agents of interference competition of FV, and (ii) trichothecenes play no role in the interaction between FG and FV. We hypothesize the following: (i) In vitro, FG stimulates the FV growth by secreting hydrolases that mobilize nutrients. In planta, suppression of plant defense by FG may additionally play a role. (ii) The biological function of fumonisin production in planta is to protect kernels shed on the ground by accumulating protective metabolites before competitors become established. Therefore, to decipher the biological function of mycotoxins, the entire life history of mycotoxin producers must be considered.

Quantitative PCR (qPCR) for estimating the presence of Fusarium and its mycotoxins in barley grains

Members within the Fusarium sambucinum species complex (FSAMSC) are able to produce mycotoxins, such as deoxynivalenol (DON), nivalenol (NIV), zearalenone (ZEN) and enniatins (ENNs) in food products. Consequently, alternative methods for assessing the levels of these mycotoxins are relevant for quick decision-making. In this context, qPCR based on key mycotoxin biosynthetic genes could aid in determining the toxigenic fungal biomass, and could therefore infer mycotoxin content. The aim of this study was to verify the use of qPCR as a technique for estimating DON, NIV, ENNs and ZEN, as well as Fusarium graminearum sensu lato (s.l.) and F. poae in barley grains. For this purpose, 53 barley samples were selected for mycobiota, mycotoxin and qPCR analyses. ENNs were the most frequent mycotoxins, followed by DON, ZEN and NIV. 83% of the samples were contaminated by F. graminearum s.l. and 51% by F. poae. Pearson correlation analysis showed significant correlations for TRI12/15-ADON with DON, ESYN1 with ENNs, TRI12/15-ADON and ZEB1 with F. graminearum s.l., as well as ESYN1 and TRI12/NIV with F. poae. Based on the results, qPCR could be useful for the assessment of Fusarium presence, and therefore, provide an estimation of its mycotoxins’ levels from the same sample.

Emesis to trichothecene deoxynivalenol and its congeners correspond to secretion of peptide YY and 5-HT.

The type B trichothecenes pollute food crops and have been associated to alimentary toxicosis resulted in emetic reaction in human and animal. This group of mycotoxins consists deoxynivalenol (DON) and four structurally related congeners: 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl deoxynivalenol (15-ADON), nivalenol (NIV) and 4-acetyl-nivalenol (fusarenon X, FX). While emesis induced by intraperitoneally dosed to DON in the mink has been related to plasma up-grading of 5-hydroxytryptamine (5-HT) and neurotransmitters peptide YY (PYY), the impact of oral dosing with DON or its four congeners on secretion of these chemical substances have not been established. The aim of this work was to contraste emetic influence to type B trichothecene mycotoxins by orally dosing and involve these influence to PYY and 5-HT. All five toxins attracted marked emetic reaction that are relevant to elevated PYY and 5-HT. The reduction in vomiting induced by the five toxins and PYY was due to blocking of the neuropeptide Y2 receptor. The inhibition of the induced vomiting response by 5-HT and all five toxins is regulated by the 5-HT3 receptor inhibitor granisetron. In a word, our results indicate that PYY and 5-HT take a key role in the emetic reaction evoked by type B trichothecenes.

Fusarium Species and Mycotoxins Associated with Sorghum Grains in Uruguay.

Grain mold and stalk rot are among the fungal diseases that cause significant losses in sorghum worldwide and are caused by different Fusarium spp. The presence of Fusarium species in sorghum grains causes yield losses and mycotoxin contamination, which represents a risk to consumers. In this study, Fusarium graminearum species complex (FGSC) had a high incidence, followed by Fusarium fujikuroi species complex (FFSC) and F. incarnatum-equiseti species complex. Within FFSC, F. proliferatum, F. andiyazi, F. fujikuroi, F. thapsinum, F. verticillioides and F. subglutinans were identified, and this was the first report of F. fujikuroi in sorghum. The most frequent toxins found in sorghum samples were deoxynivalenol (DON) and zearalenone (ZEN). The presence of fumonisins and nivalenol (NIV) was detected at low levels. This study adds new knowledge about the occurrence of Fusarium species and mycotoxins in sorghum grains. Furthermore, this is the first report in Uruguay on fungicide sensitivity for Fusarium isolates from sorghum, which constitutes an important starting point for defining management practices to minimize fungal infection and mycotoxin contamination.

Mycotoxin monitoring in Shandong province, China reveals health risks for enterohepatic diseases shifted from environment to diet: Deoxynivalenol, zearalenone and nivalenol in noodles (2019–2020)

AbstractBackground and ObjectivesHigh levels of deoxynivalenol (DON) contamination in foods can raise health risks for enterohepatic diseases. Here we report our investigation into the trichothecenes (DON, 3‐acetyl‐deoxynivalenol, 15‐acetyl‐deoxynivalenol), zearalenone (ZEA) and nivalenol (NIV) showing in the wheats‐processed noodles in Shandong, China (2019–2020).FindingsThe noodles contamination status of DON in Shandong was closed to that in China in the past 10 years: 4663.9 µg/kg at maximum level, and a range of 57.9–618.8 µg/kg by mean. However, the average levels of DON measured in the noodle samples varied largely by city. Highest levels of DON contamination were found in Binzhou: 709.09 (58.8–3220) µg/kg and Weihai: 684.79 (27.6–3850) µg/kg, respectively. Besides, NIV contamination were averagely 46.99 µg/kg in Binzhou, and ZEA contamination up to 31.4 µg/kg in Weihai, pose an increasing threat of liver/intestine inflammation associated with dietary exposure.ConclusionsThe DON contamination status of noodles in Shandong was consistent with our previous investigation in wheats and in recent 10 years in China, that increased health risks for enterohepatic diseases.Significance and NoveltyTo understand the contamination situation of DON, ZEA, and NIV in noodles, so as to assess the health risks for enterohepatic diseases caused by mycotoxin in Shandong province.

Diversity of Mycotoxins Produced by Fusarium Strains Infecting Weeds.

Although Fusarium is mainly known as an agricultural pathogen that affects monocotyledonous plants, it can also infect different species of weeds in the agricultural environment, thereby contributing to the production of mycotoxins in cereals. In this study, we present new developmental data on the diversity of mycotoxins produced by Fusarium graminearum and Fusarium avenaceum strains from weeds under field conditions. Regarding the potential for the strain dependence of mycotoxin production, this study demonstrated that all F. graminearum strains isolated from weeds and spring wheat showed high potential for deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl-deoxynivalenol (15-ADON), and nivalenol (NIV) production in spring wheat under field conditions. It was determined that F. graminearum is a typical producer of B-type trichothecenes. All strains of F. avenaceum isolated from spring wheat and weeds have the potential to produce enniatins and moniliformin in spring wheat. Each type of weed can host different Fusarium species and strains that produce completely different mycotoxins. Therefore, the distribution of mycotoxins in spring wheat grain may depend more on the Fusarium species or strains that infect the weeds than on the pathogen's host plant species. The predominance of specific mycotoxins in cereals depends on the year's weather conditions and the diversity of Fusarium species present in the field.

Occurrence of Fusarium mycotoxins in freshly harvested highland barley (qingke) grains from Tibet, China.

Highland barley, also called "qingke" in Tibetan, is mainly cultivated in the Tibetan Plateau of China and has been used as a major staple food for Tibetans. Recently, Fusarium head blight (FHB) of qingke was frequently observed around the Brahmaputra River in Tibet. Considering the importance of qingke for Tibetans, the assessment of Fusarium mycotoxin contamination is essential for food safety. In this study, a total of 150 freshly harvested qingke grain samples were obtained from three regions around the Brahmaputra River in Tibet (China) in 2020. The samples were investigated for the occurrence of 20 Fusarium mycotoxins using high-performance liquid chromatography-tandem mass spectrometry (HPLC‒MS/MS). The most frequently occurring mycotoxin was enniatin B (ENB) (46%), followed by enniatin B1 (ENB1) (14.7%), zearalenone (ZEN) (6.0%), enniatin A1 (ENA1) (3.3%), enniatin A (ENA) (1.3%), beauvericin (BEA) (0.7%), and nivalenol (NIV) (0.7%). Due to the increase in altitude, the cumulative precipitation level and average temperature decreased from the downstream to the upstream of the Brahmaputra River; this directly correlated to the contamination level of ENB in qingke, which gradually decreased from downstream to upstream. In addition, the level of ENB in qingke obtained from qingke-rape rotation was significantly lower than that from qingke-wheat and qingke-qingke rotations (p < 0.05). These results disseminated the occurrence of Fusarium mycotoxins and provided further understanding of the effect of environmental factors and crop rotation on Fusarium mycotoxins.

Effect of Temperature, Water Activity and Incubation Time on Trichothecene Production by Fusarium cerealis Isolated from Durum Wheat Grains.

Fusarium cerealis is a causal agent of Fusarium Head Blight in wheat, and it produces both deoxynivalenol (DON) and nivalenol (NIV). Nevertheless, the effect of environmental factors on the growth and mycotoxin production of this species has not been studied so far. The objective of this study was to investigate the impact of environmental factors on the growth and mycotoxin production of F. cerealis strains. All strains were able to grow in a wide range of water activity (aW) and temperatures, but their mycotoxin production was influenced by strain and environmental factors. NIV was produced at high aW and temperatures, while optimal conditions for DON production were observed at low aW. Interestingly, some strains were able to simultaneously produce both toxins, which could pose a more significant risk for grain contamination.