The enhancement of Fusarium head blight (FHB) resistance is one of the best options to reduce mycotoxin contamination in wheat. This study has aimed to verify that the genotypes with high tolerance to deoxynivalenol could guarantee an overall minimization of the sanitary risk, by evaluating the contamination of regulated, modified and emerging mycotoxins on durum wheat cvs with different degrees of FHB susceptibility, grown under different meteorological condi-tions, in 8 growing seasons in North-West Italy. The years which were characterized by frequent and heavy rainfall in spring, were also those with the highest contamination of deoxynivalenol, zearalenone, moniliformin and enniatins. The most FHB resistant genotypes resulted in the lowest contamination of all the mycotoxins but showed the highest deoxyniva-lenol-3-glucoside/deoxynivalenol ratio and moniliformin/deoxynivalenol ratio. An inverse re-lationship between the amount of deoxynivalenol and the deoxyniva-lenol-3-glucoside/deoxynivalenol ratio was recorded for all the cvs and all the years. Converse-ly, the enniatins/deoxynivalenol ratio had a less intense relationship with cv tolerance to FHB. In conclusion, even though the more tolerant cvs, showed higher relative relationships between modified/emerging mycotoxins and native/target mycotoxins than the susceptible ones, they showed lower absolute levels of contamination of both emerging and modified mycotoxins.

Deoxynivalenol (DON) is a well-known mycotoxin, responsible for outbreaks of gastrointestinal disorders in Japan. Fusarium graminearum, a parasite of cereal crops, produces this toxin and this is one of the reasons why it is important to understand its metabolism. It is possible to predict the mold’s color change and the quantity of DON synthesized throughout its lifecycle. Furthermore, a_w has been found to affect the amount of DON. This study aimed to analyze the potential of F. graminearum surface color as a predictor of DON concentration at a_w = 0.94, 0.97 and 0.99. Thus, 36 specimens were incubated at 25 °C, 12 at each a_w. After 4, 8, 12 and 16 days, 3 specimens from each a_w were collected for color analysis and DON quantification. For color analysis, photos were taken and red, green and blue (RGB) channels were measured on ImageJ software. DON was quantified through liquid chromatography (HPLC). Color changes were only observed at a_w = 0.99 because at lower a_w the molds presented high growth of white mycelium. Yet, DON increased in all cases. It was only possible to relate the colors with DON concentration at a_w = 0.99, where they presented inverse proportionality.

The objectives of the current research were to determine the levels of deoxynivalenol (DON) in four different cultivars of corn and subsequently to investigate the fate of DON during pro-cessing steps involved for the production of cornbread. The samples (n = 30) of each cultivar which were found positive were selected for the study. The average level of DON was ranged from LOD to 650 µg/kg. The amount of DON in cornflour samples were ranged from LOD to 630 µg/kg and insignificantly lower than the levels found in corn grain samples (p ≥ 0.05). Further-more, the levels of DON in corn dough samples were insignificantly higher than the levels in cornflour samples (p ≥ 0.05), with levels ranged from LOD to 645 µg/kg. However, the amount of DON in cornbread samples was significantly different from the levels found in corn grains sam-ples (p ≤ 0.05), with levels ranged from LOD to 611.5 µg/kg. The percentage reduction of DON in grains to cornbread samples was 22.4%, 35.6%, 44.5%, and 42.6% in type 1, type 2, type 3, and type 4 cultivars, respectively. The highest dietary exposure and hazard quotient (HQ) of DON was 0.13 and 0.17 µg/kg bw/d, in male and female individuals resulted from the consumption of cornbread samples, respectively.

Oats are a nutrient rich cereal used for animal feed and growing in human consumption. This cereal can be affected by Fusarium spp., causing the disease Fusarium Head Blight. This disease is caused mainly by species within the Fusarium graminearum species complex, and are also responsible for producing mycotoxins that are harmful to humans and animals. This study aimed to investigate fungal diversity in Brazilian oat samples, focusing on the Fusarium sambucinum species complex and the presence of type B trichothecenes (deoxynivalenol and its derivatives, and nivalenol) from two different regions; Paraná (PR) and Rio Grande do Sul (RS). The isolated fungi from oat grains were identified as species from the genera: Fusarium, Phoma and Alternaria. The majority of Fusarium isolates belonged to the Fusarium sambucinum species complex; identified as F. graminearum s.s., F. meridionale and F. poae. In the RS region, F. poae was the most frequent fungus, while FGSC was the most frequent in the PR region. The majority of F. graminearum s.s. isolates were of the 15-ADON genotype, while some 3-ADON genotypes were identified; however, F. meridionale and F. poae were all of the NIV genotype. Mycotoxin analysis revealed that 92% and 100% of the samples from PR and RS were contaminated with type B trichothecenes, respectively. The oats from PR were predominantly contaminated with DON, whereas NIV was predominant in oats from RS. Analysis showed that 24% of the samples were contaminated with DON at levels higher than Brazilian regulations. Co-contamination of DON, its derivatives and NIV was observed in 84% and 57.7% of the samples from PR and RS, respectively. The results provide new information on Fusarium contamination in Brazilian oats, highlighting the importance for further studies on mycotoxins.

Deoxynivalenol (DON) is a mycotoxin produced by Fusarium spp. that causes Fusarium head blight (FHB) disease in cereal crops. Ingestion of food contaminated with DON poses serious human health complications. However, the DON cytotoxicity has been mostly deduced from animal studies. In this study, we used the nematode Caenorhabditis elegans (C. elegans) as a tractable animal model to dissect the toxic effect of DON. Our results indicate that DON reduces the fecundity and lifespan of C. elegans. The real-time RT-PCR analysis showed that DON upregulates innate immunity-related genes including C17H12.8 and K08D8.5 encoding PMK-1 (mitogen activated protein kinase-1)-regulated immune effectors, and F35E12.5 encoding a CUB-like domain-containing protein. Furthermore, our RNAseq data demonstrate that out of ~ 17,000 C. elegans genes, 313 are upregulated and 166 were downregulated by DON treatment. Among the DON-upregulated genes, several are ugt genes encoding UDP-glucuronosyl transferase (UGTs) which are known to be involved in chemical detoxification. The three upregulated genes, F52F10.4 (oac-32), C10H11.6 (ugt-26) and C10H11.4 (ugt-28) encoding the O-acyltransferase homolog, UGT26 and UGT 28, respectively, are shown to contribute to DON tolerance by RNAi bacterial feeding experiment. The results of this study provide insights to the targets of DON cytotoxicity and potential mitigation measures.

Fusarium Head Blight (FHB) is a destructive disease affecting the grain yield and quality of wheat, barley, rye and triticale. Developing varieties with genetic resistance is integral to successfully managing FHB. However, significant knowledge gap exists in the genetic diversity present in triticale for FHB resistance. This information is critical for breeding new varieties of triticale as its production continues to increase. In the present study, a set of 298 winter triticale accessions from a worldwide collection were screened for their type-2 FHB resistance in an artificially inoculated misted nursery with high levels of inoculum density. Most of the triticale accessions were susceptible to FHB, and only 8% of accessions showed resistance in the field nursery screening. The resistant accessions identified in the nursery screening were selected and further screened for three years in greenhouse conditions. Seven accessions were found to show robust FHB resistance over the three years of greenhouse testing. Thirteen accessions showed significantly lower levels of Deoxynivalenol accumulation when compared to the susceptible triticale control. The accessions identified in the study will be useful in triticale and wheat breeding programs for enhancing FHB resistance and reducing DON accumulation.

Fusarium head blight (FHB) can cause contamination of cereal grain with mycotoxins. Triticale is also infected with FHB; however, it is more resistant than wheat to head infection. The aim of this study was to identify triticale lines that combine low head infection with low toxin contamination. Resistance to FHB of 15 winter triticale and three winter wheat lines was evaluated over a three-year experiment established in two locations. At the anthesis stage, heads were inoculated with Fusarium culmorum isolates. The FHB index was scored and the percentage of Fusarium-damaged kernels (FDKs) assessed. The grain was analysed for type B trichothecenes (deoxynivalenol and derivatives, nivalenol) and zearalenone content. The average FHB index was 10.7%. The proportion of FDK was 18.1% (weight) and 21.6% (number). An average content of deoxynivalenol for wheat amounted to 7.258 mg/kg and nivalenol to 5.267 mg/kg. In total, it was 12.788 m/kg of type B trichothecenes. The zearalenone content in the grain was 0.805 mg/kg. Relationships between FHB index, FDK and mycotoxin contents were statistically significant for triticale lines; however, they were stronger for FDK versus mycotoxins. Lines combing all types of FHB resistance were found, and two of them had resistance similar to that of wheat lines with the Fhb1 gene.

Stable isotope-assisted approaches can improve untargeted LC-HRMS metabolomics studies. Here, we demonstrate at the example of chemically stressed wheat that metabolome-wide internal standardization by globally 13C-labeled metabolite extract (GLMe-IS) of experimental-condition-matched biological samples can help to improve coverage of treatment-relevant metabolites and aid in the post-acquisition assessment of putative matrix effects in samples obtained upon different treatments. For this, native extracts of toxin- and mock-treated (control) wheat ears were standardized by the addition of uniformly-13C-labeled wheat ear extracts that were cultivated under similar experimental conditions (toxin-treatment and control) and measured with LC-HRMS. The results show that 996 wheat-derived metabolites were detected with the non-condition-matched 13C-labeled metabolite extract, while another 68 were only covered by the experimental-condition-matched GLMe-IS. Additional testing is performed with the assumption that GLMe-IS enables compensation for matrix effects. Although on average no severe matrix differences between both experimental conditions were found, individual metabolites may be affected as is demonstrated by wrong decisions with respect to the classification of significantly altered metabolites. When GLMe-IS was applied to compensate for matrix effects, 272 metabolites showed significantly altered levels between treated and control samples, 42 of which would not have been classified as such without GLMe-IS.

Fusarium culmorum is a major pathogen of grain crops. Infected plants accumulate deoxynivalenol (DON), 3-acetyl-deoxynivalenol (3-ADON), or nivalenol (NIV), which are mycotoxins of the trichothecene B group. These toxins are also produced by F. graminearum species complex. New trichothecenes structurally similar to trichothecenes B but lacking the carbonyl group on C-8, designated NX toxins, were recently discovered in atypical isolates of F. graminearum from North America. Only these isolates and a few strains of a yet to be characterized Fusarium species from South Africa are known to produce NX-2 and other NX toxins. Here we report that among 20 F. culmorum strains isolated from maize, wheat, and oat in Europe and Asia over a period of 70 years, 18 strains produced NX-2 simultaneously with 3-ADON and DON or NIV. Rice cultures of strains producing 3-ADON accumulated NX-2 in amounts corresponding to 2-8% of 3-ADON (1.2 - 36 mg/kg). A strain producing NIV accumulated NX-2 and NIV at comparable amounts (13.6 and 10.3 mg/kg, respectively). In F. graminearum, producers of NX-2 possess a special variant of cytochrome P450 monooxygenase encoded by TRI1 that is unable to oxidize C-8. In F. culmorum, producers and nonproducers of NX-2 possess identical TRI1; the reason for the production of NX-2 is unknown. Our results indicate that production of NX-2 simultaneously with trichothecenes B is a common feature of F. culmorum.

RNA-viruses of the genera Ambivirus, Mitovirus, Sclerotimonavirus, and Partitivirus were found in a single isolate of Fusarium graminearum. The genomes of the mitovirus, sclerotimonavirus, and partitivirus were assigned to previously described viruses, whereas the ambivirus genome putatively represents a new species, named Fusarium graminearum ambivirus 1 (FgAV1). To investigate the effect of mycoviruses on the fungal phenotype, spontaneous loss of mycoviruses during meiosis and transmission of mycoviruses into a new strain by anastomosis were used to obtain isogenic F. graminearum strains with and without mycoviruses. Notable effects observed in mycovirus-harboring strains were (i) suppression of the synthesis of trichothecene mycotoxins and their precursor trichodiene, (ii) suppression of the synthesis of the defense compound aurofusarin, (iii) stimulation of the emission of 2-methyl-1-butanol and 3-methyl-1-butanol, and (iv) increased attractiveness of fungal mycelia for fungivorous collembolans. Increased attractiveness of mycovirus-infected filamentous fungi to animal predators opens new perspectives on the ecological implications of infection of fungi with viruses.