RNA interference (RNAi) technology has been widely used to protect plants from pests and diseases. Fusarium graminearum causes Fusarium head blight (FHB) in wheat and barley, which not only results in grain yield losses but also threatens food safety due to mycotoxin contamination of grains. F. graminearum trichothecene (TRI) genes are required for trichothecene biosynthesis. Our recent study showed that TRI5 is critical for NX trichothecene production during F. graminearum infection of barley heads. To reduce mycotoxin contamination and disease using RNAi, we generated a hairpin construct targeting the TRI5 gene and introduced it into the NX-producing F. graminearum strain NRRL44211. Compared with 44211, TRI5 RNAi mutants had significantly reduced TRI5 expression and NX toxin production in vitro. Barley heads inoculated with TRI5 RNAi mutants or 44211 showed similar disease levels; however, barley heads inoculated with TRI5 RNAi mutants had significantly reduced NX toxin compared with 44211-inoculated heads. Therefore, a plant RNAi vector targeting the same TRI5 RNAi region was generated and introduced into the barley cultivar Golden Promise. FHB virulence assays showed that both FHB severity and NX-3 were significantly reduced in TRI5 RNAi transgenic lines compared with controls. Small RNA (sRNA) sequencing of both F. graminearum TRI5 RNAi mutants and barley TRI5 RNAi lines revealed sRNA reads that mapped to the TRI5 sequence, and the sRNA mapping patterns were remarkably similar in Fusarium and barley. Our results indicate that TRI5 can serve as an effective RNAi target to reduce mycotoxin contamination and improve food safety. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Introduction:Fusarium head blight (FHB) is a devastating disease of wheat that causes mycotoxin contamination in grains. Diseases like FHB have traditionally been managed with integrated strategies; but this has led to a proliferation of fungicide-resistant pathogens and soil erosion while full disease control has remained elusive. Leveraging the microbiome for more sustainable management is an alternative, however, translation of promising strategies is hampered by our limited understanding of crop microbiome differences across plant development and tissue types. Methods:We characterized fungal communities using amplicon sequencing across five developmental timepoints in wheat leaves and wheat heads, as well as in maize debris from the previous growing season. Samples were collected from two locations in Illinois, USA. We assessed how tissue type, site, developmental stage, and wheat variety contributed to mycobiome composition. Source-sink relationships among debris, leaves, and heads were evaluated, and taxa associated with high and low FHB conditions were identified. Network analyses were used to determine the roles of key fungal taxa in wheat head and maize debris microbiomes. Results:Mycobiome composition varied strongly by tissue type, though site and developmental timepoint were also important contributors. Host variety conditionally explained mycobiome variation in wheat heads, but not in leaves or debris. We also identified debris as a major fungal source to leaves early in development, but not later-and found that leaves were never a large inoculum source to head mycobiomes at either developmental stage tested. Taxa enriched under high FHB conditions in wheat heads belonged to the Ascomycota (Cladosporium, Pseudopithomyces), while taxa enriched under low FHB conditions primarily belonged to the Basidiomycota (Filobasidium, Sporobolomyces, Tilletiopsis, Entyloma). Fusarium spp. were important nodes in wheat head and maize debris microbiome networks. Discussion:This work shows that fungal movement from crop to crop across seasons, and between plant tissues within a season, shape phyllosphere microbiome dynamics and can indicate potential disease outcomes in the FHB pathosystem. As microbiome-based disease management develops alongside rapid growth in the biologicals industry and increased recognition of microbial roles in agriculture, this work highlights several promising directions. These include identifying basidiomycetous yeasts associated with low FHB, pinpointing taxa correlated with Fusarium in wheat heads and maize debris, and demonstrating that applying biocontrols to wheat leaves is unlikely to affect pathogen spread to heads. Future research should focus on controlled tests of microbe-microbe interactions and their impacts on plant immunity, disease suppression, and yield.

Mycotoxin accumulation during the malting of wheat and barley grain causes millions of dollars in annual losses for the U.S. malting and brewing industry. This research investigates the use of biofumigant treatments from plant derived metabolites to reduce grain Fusarium contamination and mycotoxin production during malting. Defatted seed meals from five glucosinolate-containing members of the Brassicaceae Family, Brassica juncea, Brassica carinata, Lepidium sativum, Sinapis alba, and Thlaspi arvense, were used to fumigate inoculated wheat and barley. We found that naturally produced gaseous allyl isothiocyanate was able to control Fusarium graminearum growth and mycotoxin contamination without harming wheat or barley germination. Treatment of Fusarium contaminated barley with volatiles from defatted Brassica juncea, in simulated malting conditions, completely prevented mycotoxin accumulation. No residual isothiocyanates were detected on the malted barley post kilning. This research demonstrates an alternative valorization of Brassicaceae seed meal byproducts as potent inhibitors of fungal contamination during malting.

Trichothecenes are a family of toxic metabolites produced by multiple fungal species. All trichothecene analogs include an epoxide-containing tricyclic structure known as 12,13-epoxytrichothec-9-ene (EPT) but differ by the presence, absence and types of substituents attached to EPT. Among the 21 known genes associated with trichothecene biosynthesis, tri14 is one of only three that are universally found in all trichothecene-producing fungi. Recent studies have revealed that the tri14-encoded protein, Tri14, enhances the biosynthetic reaction that forms EPT, a reaction previously thought to occur spontaneously. In our study, we assessed the impact of tri14 deletion on the biology of Trichoderma arundinaceum, a producer of the trichothecene harzianum A (HA). The results revealed that tri14 deletion reduced HA production by 69%, an outcome that was associated with diminished antifungal activity. To our knowledge, this is the first study showing that tri14 is required for wild-type production of a trichothecene analog by a fungal organism. tri14 deletion also had moderate effects on the expression of some other trichothecene biosynthetic genes, as well as in the production of metabolites beyond HA. These results suggest that Tri14 plays a crucial role in EPT formation, leading to diverse downstream effects on the biology of T. arundinaceum.

Fusarium graminearum is the primary causal agent of Fusarium head blight (FHB), a devastating fungal disease on wheat, barley, and other grains. During infection, F. graminearum produces trichothecene mycotoxins, predominately deoxynivalenol (DON), that contaminate grain and reduce grain yield and quality. Although DON functions as a virulence factor to promote F. graminearum spread in the wheat head, it is not essential for establishing initial infection in wheat or barley. When fungal pathogens, such as F. graminearum, infect a host plant, they secrete hundreds of protein effectors that interfere with plant immunity to promote disease. A recent study identified hundreds of putative effector-encoding genes that are conserved across six Fusarium species. In the current study, we selected a subset of 50 conserved effectors from F. graminearum PH-1 and determined their expression on wheat heads over a 7-day infection period. Gene expression analysis revealed that several genes were highly induced in wheat heads during fungal infection. One of them was a putative rhamnogalacturonan acetylesterase homolog (FgRGAE), which was also highly induced in barley heads. FHB virulence assays showed that deletion mutants of FgRGAE significantly reduced initial infection and DON accumulation in wheat and barley heads compared with wild-type controls. Replacing the FgRGAE::Hyg deletion construct with an FgRGAEORF+::Gen construct at the native locus restored FHB disease to wild-type levels in both wheat and barley heads. FgRGAE may serve as an ideal target to reduce FHB and mycotoxin contamination in wheat and barley. [Formula: see text] Copyright © 2025 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

The world is experiencing major changes in both climate and agronomic practices, which are intensifying the need to monitor plant diseases as they expand into new growing regions. Fusarium crown or foot rot is one disease of wheat and other cereals that has previously been the subject of economic concern and research primarily in arid to semiarid regions of the world. Many of the etiological agents involved in Fusarium crown rot (FCR) are cross-pathogenic in head tissues, causing the disease Fusarium head blight and increasing the risk for mycotoxin contamination of foods. During a survey of Fusarium head blight in the Midwestern U.S. state of Illinois in 2022, four soft red winter wheat fields displayed a high incidence of severe crown rot symptoms. The etiological agents of the observed symptoms were identified by translation elongation factor 1α sequencing, which revealed Fusarium graminearum, F. parabolicum, and F. acuminatum as the primary agents of FCR in Illinois wheat. The dominant Fusarium species varied across fields, with recovered isolates spanning five Fusarium species complexes, and a high diversity of likely secondary colonizers was also noted across fields. Lastly, no mycotoxins were detected in the screened wheat heads. Our results highlight the impact of local conditions in driving FCR and pathogen dynamics, even with relatively limited distances between fields. The identification of FCR agents in Illinois will serve as a resource for crop managers and breeders targeting effective control strategies in a changing agroecosystem.

The fungal pathogen Fusarium graminearum causes Fusarium head blight (FHB) on wheat and produces trichothecene mycotoxins that contaminate grains. Deoxynivalenol (DON) and its acetylated derivatives, including 3-acetyl-DON (3-ADON) and 15-acetyl-DON (15-ADON), are the most common trichothecenes found in contaminated grains, which causes food and feed safety issues. Approaches that detoxify DON can reduce FHB and mycotoxin contamination. Our previous study showed that transgenic Arabidopsis thaliana expressing a F. graminearum 3-O-acetyltransferase self-protection enzyme (FgTri101), converted DON to 3-ADON and excreted 3-ADON out of plant cells to protect plant growth and development. The goal of the current study was to identify the transporter involved in 3-ADON excretion and utilize it to reduce toxicity and FHB. To identify trichothecene transporter candidates, transcriptomic studies were conducted on FgTri101 transgenic A. thaliana seedlings treated with DON (50 mg/L, 24 h) versus untreated controls. Transcriptomic analyses revealed that three transporter genes, including two A. thaliana detoxification genes (AtDTX1 and AtDTX3) and one ABC transporter (ABCB4), were upregulated by DON treatment. Atdtx1 mutant transported 3-ADON less efficiently than Atdtx3 and Atabcb4 mutants. Therefore, the A. thaliana Col-0 mutant Atdtx1 line was transformed and expressed FgTRI101. The Atdtx1 mutant lines expressing FgTRI101 showed resistance to DON but had significantly shorter roots than the FgTRI101 Col-0 transgenic line. Furthermore, significantly less 3-ADON was detected in the media used to grow the transgenic Atdtx1 mutant seedlings expressing FgTRI101 than the Col-0 seedlings expressing FgTRI101. These data indicate that AtDTX1 is involved in efflux of 3-ADON and that at least another transporter or other mechanism is associated with 3-ADON transport.

Trichothecenes are a widespread family of sesquiterpenoid toxins that can pose significant risks to food and feed safety as well as environmental health. A defining feature of all trichothecenes is their central tricyclic 12,13-epoxytrichothec-9-ene (EPT) motif. Although the formation of the EPT central skeleton has long been presumed to be a spontaneous process, the nonenzymatic cyclization reaction forming the tetrahydropyran ring in EPT requires acid catalysis; otherwise, it occurs too slowly to sustain efficient trichothecene biosynthesis under physiological conditions. Here, we resolved this decades-old problem by identifying the missing enzymes for EPT biosynthesis. We demonstrate that the C11 hydroxyl group of universal trichothecene precursors, isotrichodiol and isotrichotriol, must be acetylated by a strictly conserved O-acetyltransferase Tri3 to furnish a better leaving group. These acetylated intermediates preferentially undergo spontaneous allylic rearrangement with water to give shunt products, trichodiol and trichotriol. Therefore, a novel cyclase, Tri14, which was previously annotated as a hypothetical protein, is required to overcome the kinetically unfavored oxide bridge closure and meanwhile suppress the spontaneous formation of any shunt products.

Trichothecenes are toxins produced by certain species from several fungal genera, including Aspergillus, Fusarium, Isaria, Paramyrothecium, Stachybotrys, Trichoderma, and Trichothecium. These toxins are of interest because they contribute to the toxigenicity, plant pathogenicity, and/or biological control activities of some fungi. All trichothecenes have the same core (12,13-epoxytrichothec-9-ene or EPT) structure but can differ from one another by the presence or absence of a macrocyclic ring formed from polyketide and isoprenoid substituents esterified to carbon atoms 4 and 15 of EPT, respectively. Genes required for formation and some modifications of EPT have been elucidated, but almost nothing is known about genes specific to the formation of the macrocyclic ring. Therefore, we used genomic, transcriptomic, metabolomic, and gene deletion analyses to identify genes that are required specifically for the formation of the macrocyclic ring. These analyses identified one gene, TRI24, that is predicted to encode an acyltransferase and that is required for macrocyclic ring formation during biosynthesis of macrocyclic trichothecenes by the fungus Paramyrothecium roridum. In addition, a TRI24 deletion mutant of P. roridum caused less severe disease symptoms on common bean and had less antifungal activity than its wild-type progenitor strain. We propose that the reduced aggressiveness and antifungal activity of the mutant resulted from its inability to produce trichothecenes with a macrocyclic ring. To our knowledge, this is the first report of a gene required specifically for the formation of the macrocyclic ring of trichothecenes and that loss of the macrocyclic ring of trichothecenes can alter the biological activities of a fungus. • TRI24 gene is found in all known macrocyclic trichothecene-producing fungi. • A tri24-deletion mutant exhibits a reduction in antifungal and plant disease activities. • TRI24 is the first described gene specific to macrocyclic trichothecene biosynthesis.

Fusarium graminearum is a primary cause of Fusarium head blight (FHB) on wheat and barley. The fungus produces trichothecene mycotoxins that render grain unsuitable for food, feed, or malt. Isolates of F. graminearum can differ in trichothecene production phenotypes (chemotypes), with individuals producing predominantly one of four toxins: 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, or NX-2. Molecular tools to diagnose chemotypes remain inefficient. This study aimed to develop a single-tube, multiplex molecular assay that can predict the four F. graminearum chemotypes. Conserved functional regions of three trichothecene biosynthetic genes (TRI1, TRI8, and TRI13) were targeted to develop a high-resolution melting (HRM) assay. Multiplex HRM analysis produced unique melting profiles for each chemotype, and was validated on a panel of 80 isolates. We applied machine learning-based linear discriminant analysis (LDA) to automate the classification of chemotypes from the HRM data, achieving a prediction accuracy of over 99%. The assay is sensitive, with a limit of detection below 0.02 ng of fungal DNA. The HRM analysis also differentiated chemotypes from a small sample of F. gerlachii, F. asiaticum, and F. vorosii isolates. Together, our results demonstrate that this simple, rapid, and accurate assay can be applied to F. graminearum molecular diagnostics and population surveillance programs.

Fusarium graminearum (Fg) is the primary causal agent of Fusarium head blight (FHB) in wheat, barley, and other small grains in North America and worldwide. FHB results in yield reduction and contaminates grain with mycotoxins that pose threats to human and livestock health. Three genetically distinct North American (NA) populations of Fg have been characterized, which are generally associated with differences in their predominant trichothecene chemotype: NA1/15-acetyl-deoxynivalenol (15-ADON), NA2/3-acetyl-deoxynivalenol (3-ADON), and NA3/3α-acetoxy, 7,15-dihydroxy-12,13-epoxytrichothec-9-ene (NX-2). Recent studies found that the NA3 population had significantly less spread on point-inoculated wheat spikes than the NA1 and NA2 populations, and NX toxins are important for Fg spread and initial infection in wheat. In this follow-up study, to compare the effect of the three populations on initial infection and mycotoxin production on different hosts, we dip-inoculated spikes of the moderately resistant wheat cultivar Alsen and the susceptible barley cultivar Voyager using five strains from each population to evaluate disease, trichothecene mycotoxin accumulation, and trichothecene production per unit of fungal biomass. In dip-inoculated wheat spikes, the NA3 population produced significantly more trichothecene per unit of fungal biomass and accumulated higher levels of trichothecene per plant biomass than the NA1 and NA2 populations, regardless of the disease levels caused by the three populations. In contrast to its critical role during wheat infection, NX toxins had no effect on barley infection. In dip-inoculated barley, the NA1 population was more infectious and caused more severe FHB symptoms than the NA2 and NA3 populations; however, the NA3 population produced significantly higher toxin per unit of fungal biomass in infected barley tissues than the NA1 population. This study provides critical information on the emerging NA3 population, which produces high levels of NX toxin and poses a potential food safety concern.

Trichothecenes are sesquiterpenoid toxins produced by diverse ascomycetes, including Fusarium. The trichothecene analog deoxynivalenol (DON) produced by the Fusarium head blight (FHB) pathogen Fusarium graminearum is a virulence factor on wheat and a major food and feed safety concern. In Fusarium, the trichothecene biosynthetic gene (TRI) cluster consists of 7–14 genes. Most TRI cluster genes are conserved and their specific roles in trichothecene biosynthesis have been determined. An exception is TRI14, which is not required for DON synthesis in vitro but is required for spread of F. graminearum in wheat heads. In the current study, gene expression analyses revealed that TRI14 was highly induced in infected wheat heads. We demonstrated that TRI14 was not only required for F. graminearum spread but also important for initial infection in wheat. Although a prior study did not detect DON in infected seeds, our analyses showed significantly less DON and fungal biomass in TRI14-mutant (designated ∆tri14)-inoculated heads than wild-type-inoculated heads. Gene expression comparison showed that the level of expression of TRI genes was similar in the wheat tissues infected with ∆tri14 or the wild type, indicating the reduced toxin levels caused by ∆tri14 may be due to less fungal growth. ∆tri14 also caused less lesion and grew less in wheat coleoptiles than the wild type. The growth of ∆tri14 in carboxymethylcellulose medium was more sensitive to hydrogen peroxide than the wild type. The data suggest that TRI14 plays a critical role in F. graminearum growth, and potentially protects the fungus from plant defense compounds.

Fusarium graminearum, the causal agent of Fusarium head blight (FHB), produces various mycotoxins that contaminate wheat grains and cause profound health problems in humans and animals. Deoxynivalenol (DON) is the most common trichothecene found in contaminated grains. Our previous study showed that Arabidopsis-expressing F. graminearum trichothecene 3-O-acetyltransferase (FgTRI101) converted DON to 3-acetyldeoxynivalenol (3-ADON) and excreted it outside of Arabidopsis cells. To determine if wheat can convert and excrete 3-ADON and reduce FHB and DON contamination, FgTRI101 was cloned and introduced into wheat cv Bobwhite. Four independent transgenic lines containing FgTRI101 were identified. Gene expression studies showed that FgTRI101 was highly expressed in wheat leaf and spike tissues in the transgenic line FgTri101-1606. The seedlings of two FgTri101 transgenic wheat lines (FgTri101-1606 and 1651) grew significantly longer roots than the controls on media containing 5 µg/mL DON; however, the 3-ADON conversion and excretion was detected inconsistently in the seedlings of FgTri101-1606. Further analyses did not detect 3-ADON or other possible DON-related products in FgTri101-1606 seedlings after adding deuterium-labeled DON into the growth media. FgTri101-transgenic wheat plants showed significantly enhanced FHB resistance and lower DON content after they were infected with F. graminearum, but 3-ADON was not detected. Our study suggests that it is promising to utilize FgTRI101, a gene that the fungus uses for self-protection, for managing FHB and mycotoxin in wheat production.

Trichothecenes are a structurally diverse family of toxic secondary metabolites produced by certain species of multiple fungal genera. All trichothecene analogs share a core 12,13-epoxytrichothec-9-ene (EPT) structure but differ in presence, absence and types of substituents attached to various positions of EPT. Formation of some of the structural diversity begins early in the biosynthetic pathway such that some producing species have few trichothecene biosynthetic intermediates in common. Cytochrome P450 monooxygenases (P450s) play critical roles in formation of trichothecene structural diversity. Within some species, relaxed substrate specificities of P450s allow individual orthologs of the enzymes to modify multiple trichothecene biosynthetic intermediates. It is not clear, however, whether the relaxed specificity extends to biosynthetic intermediates that are not produced by the species in which the orthologs originate. To address this knowledge gap, we used a mutant complementation-heterologous expression analysis to assess whether orthologs of three trichothecene biosynthetic P450s (TRI11, TRI13 and TRI22) from Fusarium sporotrichioides , Trichoderma arundinaceum , and Paramyrothecium roridum can modify trichothecene biosynthetic intermediates that they do not encounter in the organism in which they originated. The results indicate that TRI13 and TRI22 could not modify the intermediates that they do not normally encounter, whereas TRI11 could modify an intermediate that it does not normally encounter. These findings indicate that substrate promiscuity varies among trichothecene biosynthetic P450s. One structural feature that likely impacts the ability of the P450s to use biosynthetic intermediates as substrates is the presence and absence of an oxygen atom attached to carbon atom 3 of EPT.

The fungal infestation of crops can cause major economic losses. Toxins produced by the causative fungi (mycotoxins) represent a potential safety hazard to people and livestock consuming them. One such mycotoxin is deoxynivalenol (DON, also known as vomitoxin), a trichothecene associated with Fusarium Head Blight of wheat. DON is commonly found in cereal crops worldwide. A group of trichothecene mycotoxins closely related to DON, the NX toxins, have been reported to occur in the northeastern United States and southern Canada. While many commercial immunoassays are available to detect DON, there are no rapid screening assays for the NX toxins. We describe the development and isolation of three monoclonal antibodies (mAbs) specific towards two NX toxins: NX-2 and NX-3. The mAbs did not recognize DON or several other closely related trichothecenes. One of the mAbs was selected for development of an enzyme-linked immunosorbent assay (ELISA) for NX-2 and NX-3 in wheat. The dynamic ranges for the assay were 7.7 to 127 μg/kg for NX-2 and 59 μg/kg to 1540 μg/kg for NX-3 in wheat. Recoveries from spiked wheat averaged 84.4% for NX-2 and 99.3% for NX-3, with RSDs of 10.4% and 11.3%, respectively (n = 24). The results suggest that this assay can be used to screen for NX toxins in wheat at levels relevant to human food and animal feed safety.

Lay Summary Swine can be exposed to a variety of nutritional stressors that can affect their well-being and productivity. Three stressors of concern include grains with naturally occurring mycotoxins, oxidized proteins in feedstuffs due to overheating during processing, or lipids that have been damaged by excessive heating. Experiments were conducted to determine how susceptible a previously processed feedstuff was to protein oxidation and whether feeding mycotoxins, oxidized protein, or peroxidized soybean oil would affect growth performance, intestinal morphology, digestibility, and markers of oxidative stress in nursery pigs. Results indicate it was difficult to induce protein oxidation in previously processed protein by heating in a forced air oven, and if some protein oxidation did occur, there is limited effects on growth performance, digestibility, intestinal morphology, and oxidative status in nursery pigs. The data also indicated that adding an isolated mycotoxin was difficult to ensure proper mixing from which to analyze the complete diet from which to conduct animal research. At last, the data show that adding soybean oil that has been thermally processed to contain high concentrations of aldehydes will result in a dramatic reduction in animal performance, but has limited effects on digestibility, intestinal morphology, and oxidative status in nursery pigs. Two experiments (EXP) determined the susceptibility of spray-dried egg white (SDEW) to oxidation (heating at 100 degrees C for 72 h; thermally processed, TP) and whether feeding TP-SDEW, 15-acetyldeoxynivalenol (15-ADON), or peroxidized soybean oil (PSO), singularly or in combination, would affect pig performance, intestinal morphology, digestibility, and markers of oxidative stress in nursery pigs. In EXP 1, 32 pigs (7.14 kg body weight, BW) were placed individually into pens and fed diets containing either 12% SDEW, 6% TP-SDEW plus 6% SDEW, or 12% TP-SDEW. Performance was measured at the end of the 24-d feeding period with biological samples harvested following euthanasia. In EXP 2, 64 pigs (10.6 kg BW) were placed individually into pens and fed diets containing 7.5% soybean oil or PSO, 10% SDEW or TP-SDEW, and diets without or with 3 mg 15-ADON/kg diet in a 2 x 2 x 2 factorial arrangement. Performance was measured at the end of the 28-d feeding period with biological samples harvested following euthanasia. In EXP 1, dietary treatment did not affect pig performance, apparent ileal digestibility of amino acids (AAs), apparent total tract digestibility (ATTD) of gross energy (GE) or nitrogen (N), ileal crypt depth, or villi height:crypt depth ratio (P > 0.05). The effects of feeding TP-SDEW on protein damage in the plasma and liver (P < 0.05) were variable. In EXP 2, there were no three-way interactions and only one two-way interactions among dietary treatments on parameters evaluated. There was no effect of feeding TP-SDEW on ATTD of GE or N, intestinal morphology, or on oxidative markers in the plasma, liver, or ileum (P > 0.05). There was no effect of feeding diets containing added 15-ADON on ATTD of GE, ileal AA digestibility, intestinal morphology, oxidative markers in the plasma, liver, or ileum, or pig performance (P > 0.05). Feeding pigs diets containing PSO resulted in reduced ATTD of GE and N, plasma vitamin E concentration, and pig performance (P < 0.01) but did not affect intestinal morphology or oxidative markers in the liver or ileum (P > 0.05). In conclusion, it was difficult to induce protein oxidation in SDEW and when achieved there were limited effects on performance, digestibility, intestinal morphology, and oxidative status. Furthermore, singly adding 15-A-DON to a diet had no effect on the animal. At last, adding PSO reduces animal performance, but has limited effect on digestibility, intestinal morphology, and oxidative status in nursery pigs. Feeding young pigs a heated spray-dried egg white or a laboratory-purified mycotoxin have limited, if any, effects on growth performance, digestibility, intestinal morphology, and oxidative status in nursery pigs. In contrast, feeding young pigs a thermally processed soybean oil will result in a dramatic reduction in performance, but has limited effects on digestibility, intestinal morphology, and oxidative status in nursery pigs.

Fusarium head blight (FHB) is a destructive fungal disease of wheat that causes significant economic loss due to lower yields and the contamination of grain with fungal toxins (mycotoxins), particularly deoxynivalenol (DON). FHB disease spread and mycotoxin contamination has been shown to worsen at elevated CO2, therefore, it is important to identify climate-resilient FHB resistance. This work evaluates whether wheat with the Fhb1 quantitative trait locus (QTL), the most widely deployed FHB resistance locus in wheat breeding programs, provides reliable disease resistance at elevated CO2. Near-isogenic wheat lines (NILs) derived from either a highly FHB susceptible or a more FHB resistant genetic background, with or without the Fhb1 QTL, were grown in growth chambers at ambient (400 ppm) and elevated (1000 ppm) CO2 conditions. Wheat was inoculated with Fusarium graminearum and evaluated for FHB severity. At elevated CO2, the NILs derived from more FHB-resistant wheat had increased disease spread, greater pathogen biomass and mycotoxin contamination, and lower rates of DON detoxification; this was not observed in wheat from a FHB susceptible genetic background. The Fhb1 QTL was not associated with increased disease severity in wheat grown at elevated CO2 and provided reliable disease resistance.

In the United States and Canada, Fusarium graminearum (Fg) is the predominant etiological agent of Fusarium head blight (FHB), an economically devastating fungal disease of wheat and other small grains. Besides yield losses, FHB leads to grain contamination with trichothecene mycotoxins that are harmful to plant, human, and livestock health. Three genetic North American populations of Fg, differing in their predominant trichothecene chemotype (i.e., NA1/15ADON, NA2/3ADON, and NA3/NX-2), have been identified. To improve our understanding of the newly discovered population NA3 and how population-level diversity influences FHB outcomes, we inoculated heads of the moderately resistant wheat cultivar Alsen with 15 representative strains from each population and evaluated disease progression, mycotoxin accumulation, and mycotoxin production per unit Fg biomass. Additionally, we evaluated population-specific differences in induced host defense responses. The NA3 population was significantly less aggressive than the NA1 and NA2 populations but posed a similar mycotoxigenic potential. Multiomics analyses revealed patterns in mycotoxin production per unit Fg biomass, expression of Fg aggressiveness-associated genes, and host defense responses that did not always correlate with the NA3-specific severity difference. Our comparative disease assay of NA3/NX-2 and admixed NA1/NX-2 strains indicated that the reduced NA3 aggressiveness is not due solely to the NX-2 chemotype. Notably, the NA1 and NA2 populations did not show a significant advantage over NA3 in perithecia production, a fitness-related trait. Together, our data highlight that the disease outcomes were not due to mycotoxin production or host defense alone, indicating that other virulence factors and/or host defense mechanisms are likely involved.

Fusarium head blight (FHB) caused by Fusarium graminearum is one of the most devastating diseases of wheat and barley worldwide. Effectors suppress host immunity and promote disease development. The genome of F. graminearum contains hundreds of effectors with unknown function. Therefore, investigations of the functions of these effectors will facilitate developing novel strategies to enhance wheat resistance to FHB. We characterized a F. graminearum effector, FgNls1, containing a signal peptide and multiple eukaryotic nuclear localization signals. A fusion protein of green fluorescent protein and FgNls1 accumulated in plant cell nuclei when transiently expressed in Nicotiana benthamiana. FgNls1 suppressed Bax-induced cell death when co-expressed in N. benthamiana. We revealed that the expression of FgNLS1 was induced in wheat spikes infected with F. graminearum. The Fgnls1 mutants significantly reduced initial infection and FHB spread within a spike. The function of FgNLS1 was restored in the Fgnls1-complemented strains. Wheat histone 2B was identified as an interacting protein by FgNls1-affinity chromatography. Furthermore, transgenic wheat plants that silence FgNLS1 expression had significantly lower FHB severity than control plants. This study demonstrates a critical role of FgNls1 in F. graminearum pathogenesis and indicates that host-induced gene silencing targeting F. graminearum effectors is a promising approach to enhance FHB resistance. [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 .