Deoxynivalenol Content In Grain Research Articles

Genetic sources and loci for Fusarium head blight resistance in bread wheat.

Fusarium head blight (FHB) of wheat is an important disease worldwide, affecting the yield, end-use quality and threatening food safety. Genetic resources or stable loci for FHB resistance are still limited in breeding programs. A panel of 265 bread wheat accessions from China, CIMMYT-Mexico and other countries was screened for FHB resistance under 5 field experiments in Mexico and China, and a genome-wide association analysis was performed to identify QTLs associated with FHB resistance. The major locus Fhb1 was significantly associated with FHB severity and Deoxynivalenol content in grains. FHB screening experiments in multiple environments showed that Fhb1-harbouring accessions Sumai3, Sumai5, Ningmai9, Yangmai18 and Tokai66 had low FHB index, disease severity and DON content in grains in response to different Fusarium species and ecological conditions in Mexico and China. Accessions Klein Don Enrique, Chuko and Yumai34 did not have Fhb1 but still showed good FHB resistance and low mycotoxin accumulation. Sixteen loci associated with FHB resistance or DON content in grains were identified on chromosomes 1A, 1B, 2B, 3A, 3D, 4B, 4D, 5A, 5B, 7A, and 7B in multiple environments, explaining phenotypic variation of 4.43–10.49%. The sources with good FHB resistance reported here could be used in breeding programs for resistance improvement in Mexico and China, and the significant loci could be further studied and introgressed for resistance improvement against FHB and mycotoxin accumulation in grains.

Expansion of Internal Hyphal Growth in Fusarium Head Blight-Infected Grains Contributes to the Elevated Mycotoxin Production During the Malting Process.

Fusarium head blight (FHB) and the occurrence of mycotoxins is the largest food safety threat to malting and brewing grains. Worldwide surveys of commercial beers have reported that the trichothecene mycotoxin deoxynivalenol (DON) is the most frequent contaminant in beer. Although the DON content of grain generally declines during steeping due to its solubilization, Fusarium spp. can continue to grow and produce DON from steeping through the early kilning stage of malting. DON present on malt is largely extracted into beer. The objective of the current study was to localize the growth of Fusarium spp. within FHB-infected kernels by developing an improved method and to associate fungal growth with the production of DON during malting. FHB-infected barley, wheat, rye, and triticale grains that exhibited large increases in the amount of Fusarium Tri5 DNA and trichothecene mycotoxins following malting were screened for hyphal localization. The growth of fungal hyphae associated with grain and malt was imaged by scanning electron microscopy and confocal laser-scanning microscopy assisted with WGA-Alexa Fluor 488 staining, respectively. In barley, hyphae were present on or within the husk, vascular bundle, and pericarp cavities. Following malting, vast hyphal growth was observed not only in these regions but also in the aleurone layer, endosperm, and embryo. Extensive fungal growth was also observed following malting of wheat, rye, and triticale. However, these grains already had an extensive internal presence of Fusarium hyphae in the unmalted grain, thus representing an enhanced chance of fungal expansion during the malting.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Fusarium Head Blight and Associated Mycotoxins in Grains and Straw of Barley: Influence of Agricultural Practices

Fusarium head blight (FHB) is a devastating fungal disease of small-grain cereals that causes significant yield losses and mycotoxin contamination, diminishing food and feed safety worldwide. In contrast to wheat, little is known about the agricultural practices that influence FHB and Fusarium mycotoxins in barley. Thus, a nationwide survey was conducted across Switzerland for harvest samples in 2016 and 2017, accompanied with a questionnaire to obtain information about the agricultural practices in each barley field. In total, 253 grain and 237 straw samples were analyzed. In both years, F. graminearum was the predominant Fusarium species in grains followed by F. avenaceum and F. poae. Growing maize before barley was associated with increased amount of F. graminearum DNA in grains and straw as well as with elevated concentrations of deoxynivalenol in grains of barley. On the other hand, growing pasture before barley resulted in increased incidence of F. poae and concentration of numerous mycotoxins in grains (e.g., enniatins) and straw (e.g., beauvericin). Reduced tillage practices were linked to increased incidence of F. graminearum and deoxynivalenol content in grains and straw. In contrast, conventional tillage was linked to higher incidence of F. poae. Moreover, use of spring barley was associated with decreased amount of F. graminearum DNA in grains and straw, but increased incidence of F. poae and F. avenaceum. Use of the spring variety Eunova was linked to increased concentrations of several Fusarium mycotoxins in grains (e.g., enniatins and nivalenol). Furthermore, the application of strobilurin-based fungicides was associated with higher deoxynivalenol and beauvericin contents in grains. The application of plant growth regulators was associated with increased concentration of some Fusarium mycotoxins in grains (e.g., culmorin), while absence of growth regulators application was linked to elevated concentration of some other mycotoxins (e.g., nivalenol). We conclude that individual agricultural practices can suppress some FHB causing species and reduce the associated mycotoxins, but can promote others. Hence, integrated control measures combining numerous prevention and intervention strategies should be applied for the sustainable management of mycotoxins in barley.

Control of Fusarium graminearum in Wheat With Mustard-Based Botanicals: From in vitro to in planta.

Fusarium graminearum is a phytopathogenic fungus that causes Fusarium head blight in small-grain cereals, such as wheat, with significant yield reductions. Moreover, it contaminates the cereal grains with health-threatening mycotoxins, such as deoxynivalenol (DON), jeopardizing food and feed safety. Plant-based biopesticides, i.e. botanicals, have recently gained increased interest in crop protection as alternatives to synthetic chemical products. The main objective of this study was to test the control efficacy of botanicals based on white or Indian/Oriental mustard seed flours (Tillecur – Ti, Pure Yellow Mustard – PYM, Pure Oriental Mustard – POM, Oriental Mustard Bran – OMB) on F. graminearum infection and mycotoxin accumulation in wheat grain. Botanicals at 2% concentration showed a higher efficacy in inhibiting mycelium growth in vitro compared with a prothioconazole fungicide (F). In the growth chamber experiment under controlled conditions, the spraying agents reduced DON content in grain in the following order: F = Ti = PYM > POM > OMB. The antifungal activity of the botanicals may be attributed to their bioactive matrices containing isothiocyanates (ITCs) and phenolic acids. Allyl ITC was detected in POM and OMB at 8.38 and 4.48 mg g–1, while p-hydroxybenzyl ITC was found in Ti and PYM at 2.56 and 2.44 mg g–1, respectively. Considerable amounts of various phenolic acids were detected in all botanicals. Under field conditions, only the use of F significantly decreased F. graminearum infection and DON content in grain. An additional important finding of this study is that disease control was more difficult when infection was done with ascospores than conidia, which might have several potential implications considering that ascospores are more important in Fusarium head blight epidemics. Our results suggest that mustard-based botanicals are promising biopesticides for the control of Fusarium head blight in small-grain cereals, but for field applications, an appropriate formulation is necessary to stabilize and prolong the antifungal activity, especially against ascospores.

Effect of wheat (Triticum aestivum L.) resistance, Fusarium graminearum DNA content, strain potential toxin production, and disease severity on deoxynivalenol content.

Six wheat cultivars with varied resistance to Gibberella zeae (Anamorph, Fusarium graminearum Schwabe) were inoculated with six monoconidial strains of G. zeae to investigate the effect of wheat resistance to Fusarium head blight on deoxynivalenol (DON) contents. Samples were selected from grains from each plot, and heavily infected kernels and sound (uninfected) kernels prepared at 10% and 20% Fusarium-diseased kernels (FDK). The proportions of scabbed spikelets (PSS) in the field, total DON (containing DON, 3-acetyl-deoxynivalenol, and 15-acetyl-deoxynivalenol), and F. graminearum DNA (Tri5 DNA) in the samples were quantified in 2006 and 2007. PSS exhibited significant variability among the six wheat cultivars. Potential DON production also had significant differences among the six strains. DON toxin concentrations and F. graminearum DNA (Tri5 DNA) showed no significant differences among the six wheat cultivars following inoculation with similar F. graminearum strains at similar FDK levels and at similar disease severity after culture in similar conditions. DON content in grains of the tested wheat cultivars varied with inoculation strain and FDK level, but not with the resistance level of the cultivars to F. graminearum.

Genome-Wide Association Mapping of Resistance to Fusarium Head Blight Spread and Deoxynivalenol Accumulation in Chinese Elite Wheat Germplasm.

Improving resistance to Fusarium head blight (FHB) in wheat is crucial in the integrated management of the disease and prevention of deoxynivalenol (DON) contamination in grains. To identify novel sources of resistance, a genome-wide association study (GWAS) was performed using a panel of 213 accessions of elite wheat germplasm of China. The panel was evaluated for FHB severity in four environments and DON content in grains in two environments. High correlations across environments and high heritability were observed for FHB severity and DON content in grains. The panel was also genotyped with the 90K Illumina iSelect single nucleotide polymorphism (SNP) array and 11,461 SNP markers were obtained. The GWAS revealed a total of six and three loci significantly associated with resistance to fungal spread and DON accumulation in at least two environments, respectively. QFHB-2BL.1 tagged by IWB52433 and QFHB-3A tagged by IWB50548 were responsible for resistance to both fungal spread and DON accumulation. In summary, this study provided an overview of FHB resistance resources in elite Chinese wheat germplasm and identified novel resistance loci that could be used for wheat improvement.

Mycotoxins in organically versus conventionally produced cereal grains and some other crops in temperate regions

This paper presents peer-reviewed studies comparing the content of deoxynivalenol (DON), HT-2+T-2 toxins, zearalenone (ZEA), nivalenol (NIV), ochratoxin A (OTA) and fumonisins in cereal grains, and patulin (PAT) in apple and apple-based products, produced in organically and conventionally grown crops in temperate regions. Some of the studies are based on data from controlled field trials, however, most are farm surveys and some are food basket surveys. Almost half of the studies focused on DON in cereals. The majority of these studies found no significant difference in DON content in grain from the two farming systems, but several studies showed lower DON content in organically than in conventionally produced cereals. A number of the investigations reported low DON levels in grain, far below the EU limits for food. Many authors suggested that weather conditions, years, locations, tillage practice and crop rotation are more important for the development of DON than the type of farming. Organically produced oats contained mainly lower levels of HT-2+T-2 toxins than conventionally produced oats. Most studies on ZEA reported no differences between farming systems, or lower concentrations in organically produced grain. For the other mycotoxins in cereals, mainly low levels and no differences between the two farming systems were reported. Some studies showed higher PAT contamination in organically than in conventionally produced apple and apple products. The difference may be due to more efficient disease control in conventional orchards. It cannot be concluded that any of the two farming systems increases the risk of mycotoxin contamination. Despite no use of fungicides, an organic system appears generally able to maintain mycotoxin contamination at low levels. More systematic comparisons from scientifically controlled field trials and surveys are needed to clarify if there are differences in the risk of mycotoxin contamination between organically and conventionally produced crops.

Relationship of deoxynivalenol content in grain, chaff, and straw with Fusarium head blight severity in wheat varieties with various levels of resistance.

A total of 122 wheat varieties obtained from the Nordic Genetic Resource Center were infected artificially with an aggressive Fusariumasiaticum strain in a field experiment. We calculated the severity of Fusarium head blight (FHB) and determined the deoxynivalenol (DON) content of wheat grain, straw and glumes. We found DON contamination levels to be highest in the glumes, intermediate in the straw, and lowest in the grain in most samples. The DON contamination levels did not increase consistently with increased FHB incidence. The DON levels in the wheat varieties with high FHB resistance were not necessarily low, and those in the wheat varieties with high FHB sensitivity were not necessarily high. We selected 50 wheat genotypes with reduced DON content for future research. This study will be helpful in breeding new wheat varieties with low levels of DON accumulation.

A model combining agronomic and weather factors to predict occurrence of deoxynivalenol in durum wheat kernels

Deoxynivalenol (DON) produced by Fusarium graminearum in durum wheat is a major issue for the French food chain. Since this cereal is exclusively used for human consumption, each batch of grain marketed for first-stage processing must comply with the DON legal limit of 1,750 µg/kg set by the European Commission. As a response to this regulation, we have started a study to identify factors affected the DON content in durum wheat kernels. This study has been made by exploiting data from a field survey started in 2001 in French durum wheat producing regions. Over 700 field samples were harvested and grains were analysed for their DON content. For each field, agronomic parameters and weather conditions during flowering were recorded. The study of these parameters has led to the development of decision-making tools to help farmers manage the risk of DON contamination in the field. The first stage of the work was to identify critical factors involved in DON content, these being the previous crop, the tillage practices and the susceptibility of the wheat variety to Fusarium. The combination of these three factors delimits different crop systems on a DON risk assessment tool which classifies risk categories defined by their risk level expressed as a percentage probability of exceeding the DON legal limit (from 3% to 60%). Nevertheless, the main factors involved in Fusarium infection and DON production are the weather conditions prevailing during wheat flowering. The second stage was to take weather factors into consideration to develop a DON-content predictive model. The main objective of the model is to predict DON content in grain at harvest time according to the crop system and weather for the field. For users, in 85% of cases, the model accurately predicted a DON content below or above the legal limit.

On-farm experiments over 5 years in a grain maize/winter wheat rotation: effect of maize residue treatments on Fusarium graminearum infection and deoxynivalenol contamination in wheat

Over the course of 5 years, different maize residue treatments were conducted on 14 zero tillage on-farm sites in Switzerland to evaluate their effect on the development of Fusarium head blight (FHB) and the contamination with the mycotoxin deoxynivalenol (DON) in winter wheat grains and wheat straw following grain maize. Two experimental series with three and five different treatments were carried out, respectively. Fusarium graminearum (Schwabe) was the predominant FHB-causing species with an overall incidence of 15% infected wheat grains. A significant correlation between symptoms in the field, F. graminearum incidence and DON content in wheat grains and wheat straw was observed. The average DON content in both wheat grains and wheat straw was approximately 5,000 μg/kg and thus several times higher than the European maximum limit of 1,250 μg/kg for unprocessed small-grain cereals for human consumption. Of all grain samples, 74% were above the maximum limit. Pooled over both experimental series, the average reduction of DON in grains through treatments of the maize residue compared with a control treatment ranged between 21 and 38%. The effect of various other factors, including the year, the wheat variety, the site, the maize hybrid and the production system was evaluated as well. The year and the wheat variety were the most important FHB influencing factors. Over all treatments, the variety Levis showed a fivefold higher average DON content compared with the variety Titlis. From different categories of maize residue particles, intact pieces of 5-15 cm length were strongly correlated with F. graminearum incidence and DON content in grains. During the time course of this study, the recommendation from a preliminary version of the internet-based DON forecasting system FusaProg to apply or to omit a fungicide treatment was correct in 32 out of 42 cases. The results are currently being used to optimise the FusaProg models. This study has shown that in a grain maize/winter wheat rotation, the DON content in wheat grains frequently exceeded the European maximum limit, even with a thorough treatment of maize residues and less susceptible wheat varieties. Hence, in order to reduce the contamination risk in a zero tillage system, the crop rotation needs to be modified.

Biological management of Fusarium head blight and mycotoxin contamination in wheat

Fusarium head blight (FHB), caused by Gibberella zeae is a harmful disease of wheat. To manage FHB and mycotoxin contamination in wheat, field experiments were conducted from 2007 to 2008 to evaluate a total of 20 selected bioagents for their ability to inhibit perithecial production of G. zeae and for the control of FHB and deoxynivalenol (DON) contamination, in comparison with the registered fungicide Folicur (tebuconazole). All 20 bioagents significantly reduced the perithecial production compared to the untreated control. Clonostachy rosea strain ACM941 was the most effective treatment, reducing the production of perithecia by 63.7% in 2007 and 67.5% in 2008. These effects were significantly better than Folicur fungicide, which reduced perithecial production by 30.4% and 20.5%, for 2007 and 2008, respectively. When sprayed on to wheat heads, seven of the 20 bioagents significantly reduced the FHB index, one reduced Fusarium damaged kernels (FDK), and six reduced DON content in grains in 2007. ACM941 was the only treatment that significantly reduced FHB index, FDK, and DON, by 46.4%, 29.0% and 28.7%, respectively. Among the six bioagents and three formulated products evaluated in two separate field trials in 2008, ACM941 and its formulated product ACM941-CU were the only treatments that significantly reduced FHB index, FDK, and DON. The treatments reduced FHB index by 30.8% and 31.4%, FDK by 17.8% and 43.8%, and DON by 30.8% and 37.1%, for ACM941 and ACM941-CU, respectively. These effects were less marked than those of the Folicur fungicide that reduced FHB index by 98.8%, FDK by 94.2%, and DON by 92.1%. Results of this study suggest that ACM941 is a promising bioagent against G. zeae and may be used as a control measure in organic farming and in an integrated FHB and DON management program for wheat production.

A neural network model for prediction of deoxynivalenol content in wheat grain based on weather data and preceding crop

Deoxynivalenol (DON) is the most prevalent Fusarium toxin in Czech wheat samples and therefore forecasting this mycotoxin is a potentially useful tool to prevent it from entering into food chain. The data about DON content in wheat grain, weather conditions during the growing season and cultivation practices from two field experiments conducted in 2002–2005 were used for the development of neural network model designed for DON content prediction. The winning neural network is based on five input variables: a categorial variable – preceding crop, and continuous variables – average April temperature, sum of April precipitation, average temperature 5 days prior to anthesis, sum of precipitation 5 days prior to anthesis. The most important input parameters are the preceding crop and sum of precipitation 5 days prior to anthesis. The weather conditions in April, which are important for inoculum formation on crop debris are also of important contribution to the model. The weather conditions during May and 5 days after anthesis play only an insignificant role for the DON content in grain. The effect of soil cultivation was found inferior for model function as well. The correlation between observed and predicted data using the neural network model reached the coefficient <i>R</i><sup>2</sup> = 0.87.

Selection for Fusarium head blight resistance in early generations reduces the deoxynivalenol (DON) content in grain of winter and spring wheat

Abstract Fusarium head blight (FHB) results in yield losses and contamination of kernels by mycotoxins, particularly deoxynivalenol (DON). For minimizing DON content in grain, indirect selection methods would increase gains from selection compared to the costly and time‐consuming DON analysis. The aim of this study was to examine whether an early selection for fewer FHB symptoms would lead to a reduced DON content in grain after inoculation with Fusarium culmorum. Starting with a double‐cross derived population of about 1,100 genotypes, 30 F1:3 genotypes were selected for FHB rating in a two‐step selection in spring wheat with the non‐adapted resistance sources CM82036 and ‘Frontana’. In winter wheat, 30 F1:2 genotypes were selected out of a double‐cross derived population of about 600 F1 plants from crosses with German resistance sources (‘Dream’, G16‐92). Selected genotypes were grouped in three categories according to their FHB rating (low, moderate and high) and analysed afterwards for grain DON content. The three groups differed in their DON content illustrating that indirect selection should already be feasible in the earliest generations. Because of the wide genotypic ranges for DON contents within one grouping, a final DON analysis for selected materials is advisable to achieve full selection gain.

Interactions Between Barley yellow dwarf virus and Fusarium spp. Affecting Development of Fusarium Head Blight of Wheat

Interactions between Barley yellow dwarf virus (BYDV) and Fusarium species causing Fusarium head blight (FHB) in winter wheat cvs Agent (susceptible to FHB) and Petrus (moderately resistant to FHB) were studied over three years (2001–2003) in outdoor pot experiments. FHB developed more rapidly in cv. Agent than in cv. Petrus. The spread of FHB was greater in BYDV-infected plants than in BYDV-free plants. Thousand grain weight (TGW) was reduced more in Fusarium-infected heads of cv. Agent than in cv. Petrus. A highly significant negative correlation was found between disease index and TGW in cv. Agent (r = −0.916), while in cv. Petrus the correlation was less significant (r = −0.765). Virus infection reduced TGW in cv. Petrus more than in cv. Agent. In plants with both infections, TGW reductions in cv. Petrus corresponded to those of BYDV infection, and in cv. Agent TGW was more diminished than in BYDV infection. Effects of different treatments determined over three years on ergosterol contents in grain were generally similar to effects on disease indices. Grain weight per ear and ear weight of the different treatments of both cultivars largely corresponded with the TGW results. Deoxynivalenol (DON) content in grain of cv. Agent infected with Fusarium spp. was 11–25 times higher compared to the corresponding treatments in cv. Petrus. The DON content in grain of plants of the two cultivars infected with both pathogens was higher than that of plants infected only with Fusarium over the three years.

Greenhouse and Field Evaluation of Biological Control of Fusarium Head Blight on Durum Wheat.

Fusarium head blight (FHB) is a devastating disease that causes extensive yield and quality losses to wheat and barley. In durum wheat, the pathogen-produced toxin deoxynivalenol (DON) is retained in semolina at ˜50%, and the causal agent of FHB, Gibberella zeae, has a strong adverse effect on pasta color. Two bacteria and two yeast strains with known efficacy against G. zeae on hexaploid wheats were produced in liquid culture and assayed on two cultivars of durum wheat in greenhouse bioassays. All antagonists reduced FHB severity on cultivar Renville, and three of the four reduced severity on cultivar Ben, with Bacillus subtilis strain AS 43.3 decreasing FHB severity by as much as 90%. In separate greenhouse bioassays, the car-bon:nitrogen ratio of the medium used to produce antagonists did not consistently influence antagonist efficacy. All antagonist/production medium combinations but one were effective in reducing disease on both durum cultivars. Of six antagonists tested at field sites, Cryptococcus sp. OH 71.4 and C. nodaensis OH 182.9 reduced disease severity by as much as 57% in Peoria, IL, while Cryptococcus sp. OH 181.1 reduced disease severity by as much as 59% in a trial at Langdon, ND. Antagonists did not influence the DON content of grain in the Peoria trial. Relative performance indices for four antagonists calculated from greenhouse and field results on the two durum cultivars demonstrated that the bioassay location, but not the cultivar of durum, influenced the relative performance of antagonists. Yeast antagonists OH 71.4, OH 181.1, and OH 182.9 appear to have the highest potential for contributing to the reduction of FHB on du-rum wheat in the field.

Effect of Bt-Corn Hybrids on Deoxynivalenol Content in Grain at Harvest.

Concentrations of the mycotoxins deoxynivalenol (DON) and fumonisin B1 in grain were compared among Bt-transformed corn hybrids and their non-Bt isolines on 102 commercial corn fields across Ontario from 1996 to 1999. Intensities of naturally occurring populations of Ostrinia nubilalis were assessed from tunneling measurements in the stalks of non-Bt isolines in 1996 and 1997. Mean concentrations of fumonisin B1 across hybrids were <0.25 μg g-1 in every year of the study. Relationships between the concentration of fumonisin B1 and intensity of O. nubilalis or with the use of Bt corn hybrids could not be determined because the concentrations of fumonisin B1 were below the lower limit of detection in most fields (<0.1 μg g-1). However, DON was more prevalent with mean concentrations across fields from 0.42 μg g-1 in 1997 to 1.12 μg g-1 in 1999. The effect of Bt hybrids on reducing concentrations of DON was mainly dependent on the intensity of O. nubilalis in each field. Where a high intensity (stalk injury) of O. nubilalis was observed (>4 cm of tunnel per stalk in the non-Bt), the use of Bt hybrids reduced concentrations of DON by an average of 59% from concentrations in the non-Bt isoline. Where the intensity of O. nubilalis was low (<4 cm of tunneling per stalk), concentrations of DON were not different among Bt and non-Bt hybrids. Concentrations of DON were low and not different between events Bt11 and 176 among Bt hybrids. A quadratic relationship was developed showing that the concentration of DON increased with intensity of O. nubilalis feeding. This study cautiously supports the use of Bt corn to reduce the risk of high concentrations of DON at harvest in Ontario.