Integrated enzyme production in the biorefinery can significantly reduce the cost of the entire process. The purpose of the present study is to evaluate the production of two hydrolyzing enzymes (amylase and xylanase) by an edible fungus used in the biorefinery, Neurospora intermedia. The enzyme production was explored through submerged fermentation of synthetic media and a wheat-based waste stream (thin stillage and wheat bran). The influence of a nitrogen source on N. intermedia was investigated and a combination of NaNO3 and yeast extract has been identified as the best nitrogen source for extracellular enzyme production. N. intermedia enzymes showed maximum activity at 65 °C and pH around 5. Under these conditions, the maximum velocity of amylase and xylanase for starch and xylan hydrolysis was found to be 3.25 U mL−1 and 14.77 U mL−1, respectively. Cultivation of N. intermedia in thin stillage and wheat bran medium resulted in relatively high amylase (8.86 ± 0.41 U mL−1, 4.68 ± 0.23) and xylanase (5.48 ± 0.21, 2.58 ± 0.07 U mL−1) production, respectively, which makes this fungus promising for enzyme production through a wheat-based biorefinery.

Contamination by fungal and bacterial species and their metabolites can affect grain quality and health of wheat consumers. In this study, sequence analyses of conserved DNA regions of fungi and bacteria combined with determination of trichothecenes and aflatoxins revealed the microbiome and mycotoxins of wheat from different silo positions (top, middle, and bottom) and storage times (3, 6, 9, and 12 months). The fungal community in wheat on the first day of storage (T0) included 105 classified species (81 genera) and 41 unclassified species. Four species had over 10% of the relative abundance: Alternaria alternata (12%), Filobasidium floriforme (27%), Fusarium graminearum (12%), and Wallemia sebi (12%). Fungal diversity and relative abundance of Fusarium in wheat from top silo positions were significantly lower than at other silo positions during storage. Nivalenol and deoxynivalenol in wheat were 13–34% higher in all positions at 3 months compared to T0, and mycotoxins in wheat from middle and bottom positions at 6 to 12 months were 24–57% higher than at T0. The relative abundance of toxigenic Aspergillus and aflatoxins were low at T0 and during storage. This study provides information on implementation and design of fungus and mycotoxin management strategies as well as prediction models.

Species limits were investigated within the Fusarium graminearum clade (Fg clade) through phylogenetic analyses of DNA sequences from portions of 11 nuclear genes including the mating-type (MAT) locus. Nine phylogenetically distinct species were resolved within the Fg clade, and they all possess contiguous MAT1-1 and MAT1-2 idiomorphs consistent with a homothallic reproductive mode. In contrast, only one of the two MAT idiomorphs was found in five other species, four of which were putatively asexual, and the other was heterothallic. Molecular evolutionary analyses indicate the MAT genes are under strong purifying selection and that they are functionally constrained, even in species for which a sexual state is unknown. The phylogeny supports a monophyletic and apomorphic origin of homothallism within this clade. Morphological analyses demonstrate that a combination of conidial characters could be used to differentiate three species and three species pairs. Species rank is formally proposed for the eight unnamed species within the Fg clade using fixed nucleotide characters.

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

本研究旨在探究田间自然发病条件下小麦籽粒脱氧雪腐镰刀菌烯醇(deoxynivalenol, DON)的积累动态及其与病穗率、病情指数和病粒率的相关性。研究于2023年和2024年分别对感病品种‘淮麦33’和中抗品种‘宁麦13’开展田间自然发病调查。从灌浆初期开始，持续监测至延迟收获期17 d和15 d，记录并分析病穗率、病情指数、千粒重和病粒率。同时，采用ELISA法检测籽粒DON含量，并对籽粒DON含量与病穗率、病情指数及病粒率进行相关性分析。结果表明，籽粒DON在赤霉病未显症的灌浆初期已积累，含量分别为237.99、182.95 ng/g。籽粒DON、病穗率、病情指数及病粒率在灌浆期均逐渐上升，至蜡熟期略有增长，到完熟期趋于稳定，延迟收获期无明显增长且与完熟期无显著差异。千粒重在灌浆期逐渐增加，到灌浆末期已基本达最大值。同一小麦品种中，籽粒DON含量与病穗率、病情指数及病粒率均呈正相关。本研究结果可为赤霉病及籽粒DON的绿色防控、农药减施增效以及保障农产品质量安全提供理论依据。

Fungicide application to control Fusarium head blight (FHB) and accompanying mycotoxin contamination in wheat is generally performed at anthesis because wheat is most susceptible to FHB around this stage. In this study, we evaluated the effect of the timing of fungicide application on FHB and mycotoxin (deoxynivalenol and nivalenol) accumulation in wheat based on our previous finding that the late period of grain development (beyond 20 days after anthesis [DAA]) is important to determine the final toxin contamination level in wheat. Thiophanate-methyl fungicide was tested under artificial inoculation conditions in which moisture and inoculum spores were provided throughout the testing period. Eight treatments differing in application timing (anthesis, 10, 20, and 30 DAA) and in the number of applications (0 to 2) were tested for 2 years. The results indicated that fungicide application timing differentially affects FHB (disease) and mycotoxin concentration. Fungicide application at 20 DAA reduced mycotoxin concentration in matured grain without reducing FHB severity, whereas application at anthesis was crucial for reducing FHB. These results and our previous findings suggest that around 20 DAA (late milk stage) is a potentially critical timing for mycotoxin control in wheat.

为探明苯醚菌酯与戊唑醇混剂对小麦赤霉病菌的联合毒力及对赤霉病、小麦籽粒DON毒素和白粉病的田间防效，开发防治赤霉病的新药剂，采用菌丝生长速率法分别检测了苯醚菌酯、戊唑醇及其11种配比混剂对赤霉病菌的毒力，并进行了最佳配比制剂的田间药效试验。结果表明，苯醚菌酯与戊唑醇配比为1:9时增效系数为2.0804，增效作用最显著。田间药效试验中，37%苯醚菌酯∙戊唑醇SC 450 g/hm²对赤霉病病指防效和DON防效分别为92.86%和89.49%，2次药后21 d对白粉病病指防效为85.84%，均高于常规药剂多菌灵和戊唑醇，并且对小麦生长安全。37%苯醚菌酯∙戊唑醇SC对赤霉病和籽粒DON毒素防效优良，同时对白粉病兼治效果良好，可开发为赤霉病防治药剂。

Validamycin, known to interfere with fungal energy metabolism by inhibiting trehalase, has been extensively used to control plant diseases caused by Rhizoctonia spp. However, the effect of validamycin on controlling Fusarium graminearum has not been previously reported. In this study, when applied to F. graminearum in vitro, validamycin inhibited the synthesis of deoxynivalenol (DON), which is a mycotoxin and virulence factor, by decreasing trehalase activity and the production of glucose and pyruvate, which are precursors of DON biosynthesis. Because FgNTH encodes the main trehalase in F. graminearum, these effects were nullified in the FgNTH deletion mutant ΔFgNTH but restored in the complemented strain ΔFgNTHC. In addition, validamycin also increased the expression of pathogenesis-related genes (PRs) PR1, PR2, and PR5 in wheat, inducing resistance responses of wheat against F. graminearum. Therefore, validamycin exhibits dual efficacies on controlling Fusarium head blight (FHB) caused by F. graminearum: inhibition of DON biosynthesis and induction of host resistance. In addition, field trials further confirmed that validamycin increased FHB control and reduced DON contamination in grain. Control of FHB and DON contamination by validamycin increased when the antibiotic was applied with the triazole fungicide metconazole. Overall, this study is a successful case from foundational research to applied research, providing useful information for wheat protection programs against toxigenic fungi responsible for FHB and the consequent mycotoxin accumulation in grains.Copyright © 2018 Elsevier Inc. All rights reserved.

Deoxynivalenol (DON) is a vital virulence factor of Fusarium graminearum, which causes Fusarium head blight (FHB). We recently found that validamycin A (VMA), an aminoglycoside antibiotic, can be used to control FHB and inhibit DON contamination, but its molecular mechanism is still unclear. In this study, we found that both neutral and acid trehalase (FgNTH and FgATH) are the targets of VMA in F. graminearum, and the deficiency of FgNTH and FgATH reduces the sensitivity to VMA by 2.12- and 1.79-fold, respectively, indicating that FgNTH is the main target of VMA. We found FgNTH is responsible for vegetative growth, FgATH is critical to sexual reproduction, and both of them play an important role in conidiation and virulence in F. graminearum. We found that FgNTH resided in the cytoplasm, affected the localization of FgATH, and positively regulated DON biosynthesis; however, FgATH resided in vacuole and negatively regulated DON biosynthesis. FgNTH interacted with FgPK (pyruvate kinase), a key enzyme in glycolysis, and the interaction was reduced by VMA; the deficiency of FgNTH affected the localization of FgPK under DON induction condition. Strains with a deficiency of FgNTH were more sensitive to demethylation inhibitor (DMI) fungicides. FgNTH regulated the expression level of FgCYP51A and FgCYP51B by interacting with FgCYP51B. Taken together, VMA inhibits DON biosynthesis by targeting FgNTH and reducing the interaction between FgNTH and FgPK, and synergizes with DMI fungicides against F. graminearum by decreasing FgCYP51A and FgCYP51B expression.© 2021 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.