Fusarium Head Blight Management Research Articles

Testing the efficacy of a newly released fungicide, Sphaerex, for control of Fusarium Head Blight in wheat

Fusarium head blight (FHB) is a destructive disease of wheat and other small-grain cereals. FHB causes reduction in crop yield due to pre-mature bleaching of spikes. Additionally, it deteriorates the crop quality due to the production of mycotoxins. An integrated management strategy is needed to effectively manage this disease. One of the most important strategies in the FHB management toolbox is chemical control. Fungicides start losing their efficacy over time due to the development of fungicide resistance in the pathogens. This necessitates the development and testing of new fungicides with multiple active ingredients or modes of action. In this 3-year study, we evaluated the effectiveness of a new fungicide with multiple active ingredients, Sphaerex (a proprietary mix of metconazole and prothioconazole) in an FHB-susceptible soft red winter wheat cultivar, Shirley in the eastern United States. Sphaerex provided significantly better control over untreated plots for FHB Incidence, FHB Severity, and DON content across all three years. The level of control of FHB and DON by Sphaerex was found to be similar to that provided by other standard FHB fungicides. The yield of the fungicide-treated plots was statistically similar to that of the untreated plots.

Edeine B1 produced by Brevibacillus brevis reduces the virulence of a plant pathogenic fungus by inhibiting mitochondrial respiration.

Plant pathogenic fungi cause serious diseases, which result in the loss of crop yields and reduce the quality of crops worldwide. To counteract the escalating risks of chemical fungicides, interest in biological control agents to manage plant diseases has significantly increased. In this study, we comprehensively screened microbial culture filtrates using a yeast screening system to find microbes exhibiting respiratory inhibition activity. Consequently, we found a soil-borne microbe Brevibacillus brevis HK544 strain exhibiting a respiration inhibitory activity and identified edeine B1 (EB1) from the culture filtrate of HK544 as the active compound of the respiration inhibition activity. Furthermore, against a plant pathogenic fungus Fusarium graminearum, our results showed that EB1 has effects on multiple aspects of respiration with the downregulation of most of the mitochondrial-related genes based on transcriptome analysis, differential EB1-sensitivity from targeted mutagenesis, and the synergistic effects of EB1 with electron transport chain complex inhibitors. With the promising plant disease control efficacy of B. brevis HK544 producing EB1, our results suggest that B. brevis HK544 has potential as a biocontrol agent for Fusarium head blight.IMPORTANCEAs a necrotrophic fungus, Fusarium graminearum is a highly destructive pathogen causing severe diseases in cereal crops and mycotoxin contamination in grains. Although chemical control is considered the primary approach to control plant disease caused by F. graminearum, fungicide-resistant strains have been detected in the field after long-term continuous application of fungicides. Moreover, applying chemical fungicides that trigger mycotoxin biosynthesis is a great concern for many researchers. Biocontrol of Fusarium head blight (FHB) by biological control agents (BCAs) represents an alternative approach and could be used as part of the integrated management of FHB and mycotoxin production. The most extensive studies on bacterial BCAs-fungal communications in agroecosystems have focused on antibiosis. Although many BCAs in agricultural ecology have already been used for fungal disease control, the molecular mechanisms of antibiotics produced by BCAs remain to be elucidated. Here, we found a potential BCA (Brevibacillus brevis HK544) with a strong antifungal activity based on the respiration inhibition activity with its active compound edeine B1 (EB1). Furthermore, our results showed that EB1 secreted by HK544 suppresses the expression of the mitochondria-related genes of F. graminearum, subsequently suppressing fungal development and the virulence of F. graminearum. In addition, EB1 exhibited a synergism with complex I inhibitors such as rotenone and fenazaquin. Our work extends our understanding of how B. brevis HK544 exhibits antifungal activity and suggests that the B. brevis HK544 strain could be a valuable source for developing new crop protectants to control F. graminearum.

Biocontrol of Fusarium head blight in rice using Bacillus velezensis JCK-7158.

Fusarium head blight (FHB) is a destructive disease caused by several species of Fusarium, such as Fusarium graminearum and F. asiaticum. FHB affects cereal crops, including wheat, barley, and rice, worldwide. Fusarium-infected kernels not only cause reduced yields but also cause quality loss by producing mycotoxins, such as trichothecenes and zearalenone, which are toxic to animals and humans. For decades, chemical fungicides have been used to control FHB because of their convenience and high control efficacy. However, the prolonged use of chemical fungicides has caused adverse effects, including the emergence of drug resistance to pathogens and environmental pollution. Biological control is considered one of the most promising alternatives to chemicals and can be used for integrated management of FHB due to the rare possibility of environment pollution and reduced health risks. In this study, Bacillus velezensis JCK-7158 isolated from rice was selected as an ecofriendly alternative to chemical fungicides for the management of FHB. JCK-7158 produced the extracellular enzymes protease, chitinase, gelatinase, and cellulase; the plant growth hormone indole-3-acetic acid; and the 2,3-butanediol precursor acetoin. Moreover, JCK-7158 exhibited broad antagonistic activity against various phytopathogenic fungi and produced iturin A, surfactin, and volatile substances as active antifungal compounds. It also enhanced the expression of PR1, a known induced resistance marker gene, in transgenic Arabidopsis plants expressing β-glucuronidase (GUS) fused with the PR1 promoter. Under greenhouse conditions, treatments with the culture broth and suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution inhibited the development of FHB by 50 and 66%, respectively. In a field experiment, treatment with the suspension concentrate formulation of JCK-7158 at a 1,000-fold dilution effectively controlled the development of FHB with a control value of 55% and reduced the production of the mycotoxin nivalenol by 40%. Interestingly, treatment with JCK-7158 enhanced the expression of plant defense-related genes in salicylic acid, jasmonic acid, ethylene, and reactive oxygen species (ROS) signaling pathways before and after FHB pathogen inoculation. Taken together, our findings support that JCK-7158 has the potential to serve as a new biocontrol agent for the management of FHB.

A new bacterial consortia for management of Fusarium head blight in wheat

Fusarium head blight (FHB) is a significantly important disease in cereals primarily caused by Fusarium species. FHB control is largely executed through chemical strategies, which are costlier to sustainable wheat production, resulting in leaning towards sustainable sources such as resistance breeding and biological control methods for FHB. The present investigation was aimed at evaluating newly identified bacterial consortium (BCM) as biocontrol agents for FHB and understanding the morpho-physiological traits associated with the disease resistance of spring wheat. Preliminary evaluation through antagonistic plate assay and in vivo assessment indicated that BCM effectively inhibited Fusarium growth in spring wheat, reducing area under disease progress curve (AUDPC) and deoxynivalenol (DON), potentially causing type II and V resistance, and improving single spike yield (SSPY). Endurance to FHB infection with the application of BCM is associated with better sustenance of spike photosynthetic performance by improving the light energy harvesting and its utilization. Correlation and path-coefficient analysis indicated that maximum quantum yield (QY_max) is directly influencing the improvement of SSPY and reduction of grain DON accumulation, which is corroborated by principal component analysis. The chlorophyll fluorescence traits identified in the present investigation might be applied as a phenotyping tool for the large-scale identification of wheat sensitivity to FHB.

Controlling Fusarium head blight in wheat through a Mixture of varieties in an organic production system

In the organic production system, the management of diseases and pests is based on agricultural practices rather than the use of certified phytosanitary inputs. The mixture of varieties is an agricultural practice that has shown its interest not only in the management of diseases and pests but also in the increase and stability of crop yields. The objective of our study is to evaluate the performance of this practice in the management of fusarium head blight in wheat. To achieve this objective, we conducted four trials. Two trials (one on durum and the other on soft wheat) in 2019 on a certified organic farm and the two trials were repeated in 2020. During the two years of experimentation, we compared the mixture of four durum wheat varieties and the mixture of four soft wheat varieties with the monoculture varieties. In the field, we evaluated the severity of Fusarium head blight and wheat yield components as well as the grain yield. The results showed a significant difference between the different treatments for Fusarium head blight severity and yield components for both species and in both years of the experiment.

The sucrose non-fermenting-1 kinase Snf1 is involved in fludioxonil resistance via interacting with the high osmolarity glycerol MAPK kinase Hog1 in Fusarium

Fusarium head blight (FHB) caused by Fusarium graminearum complex is a worldwide devastating disease of wheat, barley, maize, and other cereals. In the field, application of fungicides is one of the main strategies for management of FHB. With the long-time usage of fungicides, resistant pathogen populations have become a new challenge for disease management. Application of new pesticide is necessary for sustainable control of this disease. The phenylpyrrole fungicide fludioxonil has been registered recently for management of FHB. However, the resistance mechanisms of F. graminearum to this compound are largely unknown. Here we isolated a biocontrol bacterium Burkholderia pyrrocina W1, which produced the antifungal compound pyrrolnitrin and showed greatly antagonistic activity towards FHB. Spontaneous mutants of pyrrolnitrin-resistant F. graminearum were induced and re-sequenced. Single base mutations were identified in the genes encoding the osmoregulation MAP kinase Hog1 and the AMP dependent kinase Snf1 in pyrrolnitrin-resistant mutants. Snf1 was further confirmed to interact with Hog1 and involved in the response of this fungus to pyrrolnitrin and its derivate, the fungicide fludioxonil. This study reveals that the Snf1 interacts with Hog1 to regulate fludioxonil resistance in a pathogenic fungus.

Hyperspectral Imaging and Selected Biological Control Agents for the Management of Fusarium Head Blight in Spring Wheat.

Fusarium spp. are important pathogens on cereals, capable of causing considerable yield losses and significantly reducing the quality of harvested grains due to contamination with mycotoxins. The European Union intends to reduce the use of chemical-synthetic plant protection products (csPPP) by up to 50% by the year 2030. To realize this endeavor without significant economic losses for farmers, it is crucial to have both precise early detection of pathogens and effective alternatives for csPPP. To investigate both the early detection of Fusarium head blight (FHB) and the efficacy of selected biological control agents (BCAs), a pot experiment with spring wheat (cv. 'Servus') was conducted under semi-field conditions. Spikes were sprayed with different BCAs prior to inoculation with a mixture of F. graminearum and F. culmorum conidia. While early detection of FHB was investigated by hyperspectral imaging (HSI), the efficiency of the fungal (Trichoderma sp. T10, T. harzianum T16, T. asperellum T23 and Clonostachys rosea CRP1104) and bacterial (Bacillus subtilis HG77 and Pseudomonas fluorescens G308) BCAs was assessed by visual monitoring. Evaluation of the hyperspectral images using linear discriminant analysis (LDA) resulted in a pathogen detection nine days post inoculation (dpi) with the pathogen, and thus four days before the first symptoms could be visually detected. Furthermore, support vector machines (SVM) and a combination of LDA and distance classifier (DC) were also able to detect FHB symptoms earlier than manual rating. Scoring the spikes at 13 and 17 dpi with the pathogen showed no significant differences in the FHB incidence among the treatments. Nevertheless, there is a trend suggesting that all BCAs exhibit a diminishing effect against FHB, with fungal isolates demonstrating greater efficacy compared to bacterial ones.

Optimal timing of fungicide application to manage Fusarium head blight in winter barley.

Fusarium head blight is among the chief threats to profitable barley production, and fungicide applications are one of two main strategies for reducing FHB damage to barley crops. However, there is very little published information on optimal timing of such applications. A four-year field study was conducted with winter barley in Raleigh, North Carolina, to compare three timings for fungicide application: 50% spike emergence (Zadoks growth stage or GS 55), 100% spike emergence (GS 59), and six days after GS 59. Three winter barley cultivars with varying levels of FHB resistance were grown for four successive years (2018-2021) in a split-plot experiment and inoculated each spring with Fusarium-infected corn spawn. Three fungicides were compared: propiconazole + pydiflumetofen (Miravis Ace), prothioconazole + tebuconazole (Prosaro), and metconazole (Caramba). Correlations among visual symptoms and assays of harvested grain were modest, and were weakened by fungicide applications. Across years and cultivars, deoxynivalenol (DON) and percent Fusarium-infected kernels were most reduced relative to the nontreated control by fungicide applications at the latest timing (GS 59 + 6 d). The early (GS 55) timing resulted in DON not significantly different from the nontreated control. Based on these results, it is recommended that to minimize damage from FHB, fungicide should be applied to winter barley several days after GS 59 (100% spike emergence), and not before GS 59.

Trichoderma gamsiiT6085, a biocontrol agent of Fusarium head blight, modulates biocontrol‐relevant defence genes expression in wheat

AbstractTo enhance the framework of the mechanisms of action used by Trichoderma gamsii T6085 for the control of Fusarium head blight (FHB), this work investigated its ability to modulate the expression of defence‐related genes of wheat (Triticum aestivum ‘Apogee’) in response to endophytic colonization of plant tissues. Changes in relative expression of pal1, pr1, pgip2 and lox1 genes were assessed over time in wheat roots, in spikes colonized by T6085 alone and both T6085 and Fusarium graminearum, and in leaves from wheat seedlings root‐inoculated with T6085. Results indicate the ability of T6085 to induce local and systemic defence responses in wheat plants in the presence of one of the causal agents of FHB. There was a general significant up‐regulation of the plant defence‐related genes analysed, especially in the first days after the application of T6085. According to these results, modulation of plant defence genes could be included within the arsenal of mechanisms used by T6085 when applied to wheat, an additional feature of interest in the management of FHB. To evaluate the effect of the plant genotype on the ability of T6085 to endophytically colonize roots, root colonization was assessed on four cultivars of T. aestivum and two cultivars of T. durum. Data showed that roots of only two T. aestivum cultivars were endophytically colonized by T6085, similar to cv. Apogee used here as control, thus demonstrating an effect of the host genotype on the endophytic ability of T6085.

Modelling the effect of pH and H2S on the germination of F. graminearum spores under different temperature conditions

Fusarium graminearum (F. graminearum) is a vital pathogen of Fusarium head blight (FHB). Hydrogen sulfide (H2S), which can be induced by stress in plants as a fungal inhibitor, affects the germination of spores through the detection of environmental factors such as temperature and pH. Based on mathematical models, F. graminearum was treated with different temperatures, pH, and H2S concentration to investigate spore germination events. This paper considered the synergistic effects of temperature and pH on spores in order to determine the optimal germination environment. Under these circumstances, the inhibition of spore germination with different concentrations of H2S was quantified. The results suggested that the germination time negatively correlates with the germinating rate. An increase in temperature altered the weak alkali preference of F. graminearum spores. At 28 °C, spores were more sensitive to the changes in pH. H2S gas could delay the germinating process significantly, however the required H2S concentration varied with environmental changes. This paper provides a perspective on the synergistic effect of temperature and pH on spore germination and contributes to determining the concentration of H2S as a management of FHB.

GSEYOLOX-s: An Improved Lightweight Network for Identifying the Severity of Wheat Fusarium Head Blight

Fusarium head blight (FHB) is one of the most detrimental wheat diseases. The accurate identification of FHB severity is significant to the sustainable management of FHB and the guarantee of food production and security. A total of 2752 images with five infection levels were collected to establish an FHB severity grading dataset (FHBSGD), and a novel lightweight GSEYOLOX-s was proposed to automatically recognize the severity of FHB. The simple, parameter-free attention module (SimAM) was fused into the CSPDarknet feature extraction network to obtain more representative disease features while avoiding additional parameters. Meanwhile, the ghost convolution of the model head (G-head) was designed to achieve lightweight and speed improvements. Furthermore, the efficient intersection over union (EIoU) loss was employed to accelerate the convergence speed and improve positioning precision. The results indicate that the GSEYOLOX-s model with only 8.06 MB parameters achieved a mean average precision (mAP) of 99.23% and a detection speed of 47 frames per second (FPS), which is the best performance compared with other lightweight models, such as EfficientDet, Mobilenet-YOLOV4, YOLOV7, YOLOX series. The proposed GSEYOLOX-s was deployed on mobile terminals to assist farmers in the real-time identification of the severity of FHB and facilitate the precise management of crop diseases.

Effects of Fungicides and Cultivar Resistance on Fusarium Head Blight and Deoxynivalenol in Spring Barley from 2014 to 2019

Spring barley production and quality in the United States is severely impacted by Fusarium head blight (FHB), primarily caused by Fusarium graminearum. Management of FHB is best accomplished using an integrated approach including resistant varieties and fungicides. Field experiments were established from 2014 to 2019 to quantify the effects of host resistance, fungicide, and fungicide timing on management of FHB and deoxynivalenol (DON) and yield protection in spring barley. Three separate research objectives were investigated using multiyear and multilocation experiments. These included investigating the efficacy of prothioconazole + tebuconazole applied at either Feekes growth stage (FGS) 10.5 (full head) or 3 to 7 days after FGS 10.5; the efficacy of sequential fungicide applications occurring at both FGS 10.5 and 3 to 7 days after FGS 10.5 using prothioconazole + tebuconazole, metconazole, prothioconazole, or tebuconazole; and the efficacy and timing of pydiflumetofen + propiconazole. Pooled analysis results suggest that metconazole, prothioconazole + tebuconazole, and pydiflumetofen + propiconazole are all effective fungicides for reducing DON, reducing FHB, and protecting yield. The use of sequential fungicide applications with one occurring at FGS 10.5 and another at 3 to 7 days after FGS 10.5 provided greater suppression than a single application at FGS 10.5. The greatest DON reduction from pydiflumetofen + propiconazole occurred when applied at full head or 3 to 7 days after full head. Across all research objectives, the most effective single fungicide application timing to reduce FHB, reduce DON, and protect yield in barley is 3 to 7 days after FGS 10.5.

Effect of Nozzle Configuration and Ground Sprayer Speed on Fusarium Head Blight Management in Wheat

Fusarium head blight (FHB), caused primarily by Fusarium graminearum in the United States, is the most important disease of wheat in Kentucky and the surrounding region. In addition to reduced grain yields, grain quality also can be affected due to reduced test weights and contamination of harvested grain by associated mycotoxins, such as deoxynivalenol (DON). Although application of a foliar fungicide during the beginning anthesis growth stage is one of the primary practices used to manage FHB and DON, a major limiting factor in achieving greater efficacy has been fungicide coverage of wheat heads. This research evaluated different nozzle configurations and ground sprayer speeds for their effect on coverage of simulated wheat heads and management of FHB and DON in field trials conducted in 2017 to 2019 at the University of Kentucky Research and Education Center in Princeton, KY. Based on the results from this research, only minor differences in simulated wheat head coverage were observed across nozzle configurations and sprayer speeds. Depending on the nozzle configuration being used, applicators may need to adjust their sprayer speed to achieve maximum control of FHB.

Effects of Metconazole + Prothioconazole, Pydiflumetofen + Propiconazole, and Variety Resistance on Fusarium Head Blight and Yield in Hard Red Spring Wheat

Fusarium head blight (FHB), caused primarily by Fusarium graminearum (Schwabe), is one of the most significant diseases of hard red spring wheat (HRSW) in North Dakota. Implementing integrated management practices such as host resistance and fungicides can be used to manage FHB and the associated mycotoxin deoxynivalenol (DON). However, depending on the production year in North Dakota, both management tools might not be needed for FHB. The objective of this research was to evaluate fungicide premixes and varietal resistance on suppression of FHB, suppression of DON, and economic response in diverse FHB environments in dryland HRSW. Seven field experiments were conducted at dryland locations from 2019 to 2021. Two HRSW varieties, WB-Mayville (susceptible) and ND-VitPro (moderately resistant) served as the main plots, and seven fungicide treatments, including a nontreated control, served as the subplots. Based on disease levels and local weather data (relative humidity, rainfall, and temperature), field experiments were categorized into four FHB management environments (high, moderate, low, and no disease) to assess the effectiveness of management tools in field situations faced by HRSW growers. The fungicide premixture treatments of metconazole + prothioconazole and pydiflumetofen + propiconazole provided similar or better suppression of FHB and DON when compared with FHB fungicide standards. The results suggest that the use of fungicides on a moderately resistant variety provided a more favorable economic response when compared with their use on a susceptible variety in moderate and low FHB environments. The results from this study will help guide FHB management decisions in dryland HRSW.

Minimal impacts on the wheat microbiome when Trichoderma gamsii T6085 is applied as a biocontrol agent to manage fusarium head blight disease.

Fusarium head blight (FHB) is a major fungal disease that causes severe yield and quality loss in wheat. Biological control can be integrated with other management strategies to control FHB. For this purpose, Trichoderma gamsii strain T6085 is a potential biocontrol agent to limit the infection of F. graminearum and F. culmorum in wheat. However, the possible impacts of T. gamsii T6085 on the broader microbiome associated with the wheat plant are not currently understood. Therefore, we identified bacteria and fungi associated with different wheat tissues, including assessment of their relative abundances and dynamics in response to the application of T6085 and over time, using amplicon sequencing. Residues of the prior year’s wheat crop and the current year’s wheat spikes were collected at multiple time points, and kernel samples were collected at harvest. DNA was extracted from the collected wheat tissues, and amplicon sequencing was performed to profile microbiomes using 16S v4 rRNA amplicons for bacteria and ITS2 amplicons for fungi. Quantitative PCR was performed to evaluate the absolute abundances of F. graminearum and T. gamsii in different wheat tissues. Disease progression was tracked visually during the growing season, revealing that FHB severity and incidence were significantly reduced when T6085 was applied to wheat spikes at anthesis. However, treatment with T6085 did not lessen the F. graminearum abundance in wheat spikes or kernels. There were substantial changes in F. graminearum abundance over time; in crop residue, pathogen abundance was highest at the initial time point and declined over time, while in wheat spikes, pathogen abundance increased significantly over time. The predominant bacterial taxa in wheat spikes and kernels were Pseudomonas, Enterobacter, and Pantoea, while Alternaria and Fusarium were the dominant fungal groups. Although the microbiome structure changed substantially over time, there were no community-scale rearrangements due to the T6085 treatment. The work suggests several other taxa that could be explored as potential biocontrol agents to integrate with T6085 treatment. However, the timing and the type of T6085 application need to be improved to give more advantages for T6085 to colonize and reduce the F. graminearum inoculum in the field.

Diversity of Fusarium community assembly shapes mycotoxin accumulation of diseased wheat heads.

Fusarium head blight (FHB) is a major disease worldwide on cultivated cereals, caused by several Fusarium species. FHB can cause not only yield reduction but also accumulation of mycotoxins in the grain contaminating the food supply. Much of the earlier research has focused on Fusarium pathogenesis, conditions required for disease development and toxin accumulation, and FHB management. However, the Fusarium community composition within the micro-habitat of a single diseased wheat head in the field has had limited investigation. Similarly, the relationship between the Fusarium community structure and mycotoxin accumulation within diseased heads remains unclear. In the present study, we investigated the Fusarium community in diseased heads sampled from different geographical sites in China. Several sites in Shandong province formed a transitional region which contained highly variable profiles of Fusarium OTUs, where a single diseased head could contain more than 10 Fusarium OTUs. Mycotoxin accumulation was independent of geographical properties, however, deoxynivalenol, 15-acetyldeoxynivalenol and zearalenone concentrations showed a significant negative correlation with Fusarium diversity on diseased heads while a significant positive correlation between nivalenol concentration and Fusarium diversity was observed. Taken together, the Fusarium OTU diversity within diseased heads in the field significantly influences mycotoxin accumulation, providing an important point to consider in FHB disease management and mycotoxin research.

Foliar fungicides provide chemical control of Fusarium head blight of wheat in South Africa

Chemical control of a yield-limiting, quality-reducing wheat disease like Fusarium head blight (FHB) is an important management strategy; however, no fungicides are registered against it in South Africa. The aim of this study was to determine foliar fungicides and seed treatment efficacy for FHB management. Three commercial fungicides and two seed treatments were evaluated in a naturally infested field during 2011 and 2012. Significant interactions between the seed treatments and the foliar fungicides were obtained for FHB incidence and yield. When the fungicide Abacus® was sprayed in combination with either of the two seed treatments, FHB incidence was significantly decreased compared with use of the fungicide alone. Prosaro® sprayed in combination with Galmano® Plus as a seed treatment significantly decreased yield compared with the use of Prosaro alone or in combination with Vitavax® Plus as a seed treatment. The fungicide treatments significantly reduced FHB incidence and the percentage of Fusarium-damaged kernels (%FDK) when compared with control treatments, and significantly increased the yield. A weak but significant correlation was recorded between deoxynivalenol (DON) and %FDK. Strong negative correlations were observed between hectolitre mass (HLM) and FHB incidence and %FDK, respectively, and between yield and %FDK. These results indicate that the chemical control of FHB of wheat can be used to manage the disease in South Africa. Future research, therefore, must focus on integrating chemical control with host resistance to obtain optimal results.

Anwendung von Silizium im Wurzelbereich zur Bekämpfung der Ährenfusariose bei Weizen unter Feldbedingungen

Anwendung von Silizium im Wurzelbereich zur Bekämpfung der Ährenfusariose bei Weizen unter Feldbedingungen

Implications of Crop Rotation and Fungicide on Fusarium and Mycotoxin Spectra in Manitoba Barley, 2017-2019.

Fusarium head blight (FHB) is one of the most important diseases of barley in Manitoba province (western Canada), and other major barley producing regions of the world. Little is known about the Fusarium species and mycotoxin spectra associated with FHB of barley in Manitoba. Hence, barley grain samples were collected from 149 commercial fields from 2017 to 2019, along with information on respective cropping history, and analyzed with respect to Fusarium species spectra, abundance, chemotype composition, and mycotoxin profiles. Fusarium poae was the predominant Fusarium species associated with FHB of barley in Manitoba, followed by F. graminearum, and F. sporotrichioides; F. equiseti and F. avenaceum were also detected but at low levels. F. poae strains with the nivalenol (NIV) chemotype and F. graminearum strains with 3-acetyl deoxynivalenol (3-ADON) and 15-acetyl deoxynivalenol (15-ADON) chemotypes were commonly detected in the barley grain samples. Nivalenol (597.7, 219.1, and 412.4 µg kg−1) and deoxynivalenol (DON) (264.7, 56.7, and 65.3 µg kg−1) were the two most prevalent mycotoxins contaminating Manitoba barley in 2017, 2018 and 2019, respectively. A substantially higher DON content was detected in grain samples from barley fields with cereals as a preceding crop compared to canola and flax. Furthermore, F. poae proved less sensitive to four triazole fungicides (metconazole, prothioconazole+tebuconazole, tebuconazole, and prothioconazole) than F. graminearum. Findings from this research will assist barley producers with improved understanding of FHB threat levels and optimizing practices for the best management of FHB in barley.

Triticonazole enantiomers induced enantioselective metabolic phenotypes in Fusarium graminearum and HepG2 cells

The management of Fusarium head blight relies heavily on triazole fungicides. Most of triazole fungicides are chiral, and their enantioselective effects on metabolic phenotypes are poorly understood. Herein, we analyzed the bioactivity of triticonazole against Fusarium graminearum, and 1H-nuclear magnetic resonance-based metabolomics was used to assess the metabolic disturbances of triticonazole enantiomers in Fusarium graminearum and human hepatocarcinoma cells. Results indicated that the bioactivity of R-triticonazole was 4.28-fold higher than its antipode since it bound stronger with fungal CYP51B and induced more abnormal metabolic processes of Fusarium graminearum, including lipid metabolism, glycolysis, and amino acid metabolism. In human hepatocarcinoma cells, pathways of "alanine, aspartic acid and glutamate metabolism" and "pyruvate metabolism" were disturbed significantly by R-triticonazole; "phenylalanine metabolism" and "taurine-hypotaurine metabolism" were abnormal in the exposure of S-triticonazole. These results suggested that R- and S-triticonazole could affect different metabolic pathways of human hepatocarcinoma cells, and the massively use of inefficient S-triticonazole should be avoided. Our data will help to better understand the enantioselectivity of chiral pesticides and provide a reference for the development of green pesticides.