Deoxynivalenol In Wheat Grain Research Articles

A Surface-Enhanced Raman Spectroscopy-Based Aptasensor for the Detection of Deoxynivalenol and T-2 Mycotoxins.

The quality of food is one of the emergent points worldwide. Many microorganisms produce toxins that are harmful for human and animal health. In particular, mycotoxins from Fusarium fungi are strictly controlled in cereals. Simple and robust biosensors are necessary for 'in field' control of the crops and processed products. Nucleic acid-based sensors (aptasensors) offer a new era of point-of-care devices with excellent stability and limits of detection for a variety of analytes. Here we report the development of a surface-enhanced Raman spectroscopy (SERS)-based aptasensor for the detection of T-2 and deoxynivalenol in wheat grains. The aptasensor was able to detect as low as 0.17% of pathogen fungi in the wheat grains. The portable devices, inexpensive SERS substrate, and short analysis time encourage further implementation of the aptasensors outside of highly equipped laboratories.

Recognition of glycoside hydrolase 12 proteins by the immune receptor RXEG1 confers Fusarium head blight resistance in wheat.

Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating disease in wheat (Triticum aestivum) that results in substantial yield losses and mycotoxin contamination. Reliable genetic resources for FHB resistance in wheat are lacking. In this study, we characterized glycoside hydrolase 12 (GH12) family proteins secreted by F. graminearum. We established that two GH12 proteins, Fg05851 and Fg11037, have functionally redundant roles in F. graminearum colonization of wheat. Furthermore, we determined that the GH12 proteins Fg05851 and Fg11037 are recognized by the leucine-rich-repeat receptor-like protein RXEG1 in the dicot Nicotiana benthamiana. Heterologous expression of RXEG1 conferred wheat responsiveness to Fg05851 and Fg11037, enhanced wheat resistance to F. graminearum and reduced levels of the mycotoxin deoxynivalenol in wheat grains in an Fg05851/Fg11037-dependent manner. In the RXEG1 transgenic lines, genes related to pattern-triggered plant immunity, salicylic acid, jasmonic acid, and anti-oxidative homeostasis signalling pathways were upregulated during F. graminearum infection. However, the expression of these genes was not significantly changed during infection by the deletion mutant ΔFg05851/Fg11037, suggesting that the recognition of Fg05851/Fg11037 by RXEG1 triggered plant resistance against FHB. Moreover, introducing RXEG1 into three other different wheat cultivars via crossing also conferred resistance to F. graminearum. Expression of RXEG1 did not have obvious deleterious effects on plant growth and development in wheat. Our study reveals that N. benthamiana RXEG1 remains effective when transferred into wheat, a monocot, which in turn suggests that engineering wheat with interfamily plant immune receptor transgenes is a viable strategy for increasing resistance to FHB.

Desativação do desoxinivalenol em grãos de trigo tratados com gás amônia e seu efeito na dieta de Rattus norvegicus

ABSTRACT Fusarium head blight, also known as fusariosis, is caused by a fungus called Fusarium graminearum that produces the mycotoxin deoxynivalenol (DON). This toxin causes problems to human and animal health. Ammonia gas has been shown to be effective in deactivating mycotoxins. The objectives of this study were to evaluate the effectiveness of ammonia gas in the deactivation of DON in wheat grains, the effect of this treatment on its protein composition and the toxicity in rats fed with ammoniated wheat grains. Wheat samples were exposed to ammonia gas at concentrations of 0% (Control), 0.5%, 1% and 1.5%. It was observed that ammonia gas was effective in deactivating DON at concentrations of 1% and 1.5%. There was no difference in crude protein observed in the bromatological analysis of treated wheat grains in relation to the control. Regarding the toxicity of wheat grains treated with ammonia in the feeding of Wistar rats (Rattus norvegicus), no histopathological alterations were observed in the liver, kidneys, intestine and in the hematological profile. The results of this study demonstrated that the treatment of wheat with ammonia gas can contribute to the deactivation of DON without compromising its protein composition and animal health.

Electrochemical Degradation and Toxicity Evaluation of Deoxynivalenol in Wheat Grains

Deoxynivalenol (DON), one of the most common mycotoxins threatening food production and safety, is contaminating wheat and other cereals worldwide. Developing an effective method to degrade DON in cereals is favorable to protect human health and reduce economic losses. This work aimed to study electrochemical degradation of DON at different conditions in aqueous solution and wheat grains for guiding practical application. In aqueous solution, electrochemical reduction degraded 49.36 ± 0.81% of DON at −9.0 V after 60 min; electrochemical oxidation readily degraded 100% of DON within 20 min at 1.5 V and was applied in wheat grains, degrading 91.07 ± 1.83%. The structure of degradation products was identified through mass spectrometry. Furthermore, toxicity of the products was evaluated by ECOSAR software. LC50 and EC50 of all products were higher than 598 mg/L, and ChVs were higher than 111 mg/L, suggesting that all products are not harmful. Our developed electrochemical degradation method of DON in wheat grains does not add harmful chemicals and is environmentally friendly, which is potential to degrade DON in cereals.

Novel Soil Bacterium Strain Desulfitobacterium sp. PGC-3-9 Detoxifies Trichothecene Mycotoxins in Wheat via De-Epoxidation under Aerobic and Anaerobic Conditions.

Trichothecenes are the most common mycotoxins contaminating small grain cereals worldwide. The C12,13 epoxide group in the trichothecenes was identified as a toxic group posing harm to humans, farm animals, and plants. Aerobic biological de-epoxidation is considered the ideal method of controlling these types of mycotoxins. In this study, we isolated a novel trichothecene mycotoxin-de-epoxidating bacterium, Desulfitobacterium sp. PGC-3-9, from a consortium obtained from the soil of a wheat field known for the occurrence of frequent Fusarium head blight epidemics under aerobic conditions. Along with MMYPF media, a combination of two antibiotics (sulfadiazine and trimethoprim) substantially increased the relative abundance of Desulfitobacterium species from 1.55% (aerobic) to 29.11% (aerobic) and 28.63% (anaerobic). A single colony purified strain, PGC-3-9, was isolated and a 16S rRNA sequencing analysis determined that it was Desulfitobacterium. The PGC-3-9 strain completely de-epoxidated HT-2, deoxynivalenol (DON), nivalenol and 15-acetyl deoxynivalenol, and efficiently eliminated DON in wheat grains under aerobic and anaerobic conditions. The strain PGC-3-9 exhibited high DON de-epoxidation activity at a wide range of pH (6–10) and temperature (15–50 °C) values under both conditions. This strain may be used for the development of detoxification agents in the agriculture and feed industries and the isolation of de-epoxidation enzymes.

A quinone-dependent dehydrogenase and two NADPH-dependent aldo/keto reductases detoxify deoxynivalenol in wheat via epimerization in a Devosia strain

The Fusarium mycotoxin deoxynivalenol (DON) is typically controlled by fungicides. Here, we report DON detoxification using enzymes from the highly active Devosia strain D6-9 which degraded DON at 2.5 μg/min/108 cells. Strain D6-9 catabolized DON to 3-keto-DON and 3-epi-DON, completely removing DON in wheat. Genome analysis of three Devosia strains (D6-9, D17, and D13584), with strain D6-9 transcriptomes, identified three genes responsible for DON epimerization. One gene encodes a quinone-dependent DON dehydrogenase QDDH which oxidized DON into 3-keto-DON. Two genes encode the NADPH-dependent aldo/keto reductases AKR13B2 and AKR6D1 that convert 3-keto-DON into 3-epi-DON. Recombinant proteins expressed in Escherichia coli efficiently degraded DON in wheat grains. Molecular docking and site-directed mutagenesis revealed that residues S497, E499, and E535 function in QDDH's DON-oxidizing activity. These results advance potential microbial and enzymatic elimination of DON in agricultural samples and lend insight into the underlying mechanisms and molecular evolution of DON detoxification.

Effect of deoxynivalenol detoxification by ozone treatment in wheat grains

Considering the wide existence of mycotoxin deoxynivalenol (DON) in wheat and derived products, finding ways to detoxify DON in wheat grains as original resources for food-chain contamination is very important to protect human health and reduce economic losses. This study aimed to evaluate the effectiveness of destroying DON in wheat via ozonation under different conditions, such as moisture content (MC), ozone concentration, exposure time, and form of raw-material. The achieved data showed that DON reduction significantly improved with increased ozone concentration and exposure time. The whole wheat flour (WWF) was easier to degrade than the wheat kernels. Higher MC decreased larger amounts of DON. The maximum reduction of DON was 20.10% for the MC group, compared with the 11.79% and 16.29% for the other MC groups. DON concentration decreased from 3.89 mg/kg to 0.83 mg/kg under the generally recognized Maximum Residue Limit (MRL) level of 1 mg/kg, when WWF was treated with 100 mg/L of ozone treatment for 60 min. The first-order kinetic model established in this work showed a good R-squared value (R2 > 0.877) and was consistent with the results. Therefore, ozonation is an effective and rapid way to degrade DON in wheat, especially in whole wheat flour.

Deoxynivalenol content in wheat dust versus wheat grain: a comparative study

The present study, set up in the growing season 2011-2012, was designed to obtain quantitative data on the occurrence of deoxynivalenol in wheat grain and the corresponding wheat dust. The field experiment consisted of a complete randomised block design with five wheat varieties sown on a field on which maize was grown in the previous season. The impact of the tillage method and the influence of the wheat variety resistance on the deoxynivalenol content of wheat and wheat dust were investigated. The accumulation of deoxynivalenol in wheat dust was confirmed and a sigmoidal relationship between the deoxynivalenol content in wheat dust versus wheat grain was determined. Deoxynivalenol reduction was obtained by ploughing and by sowing moderately resistant wheat varieties. As wheat dust provides equal results and solves the problem of heterogeneity during sampling of conventional wheat matrix, the sampling of wheat dust can be considered as a promising alternative.

Recent advances in the rapid acoustic screening of deoxynivalenol in wheat grains

Deoxynivalenol (DON) is a natural and ubiquitous toxic metabolite produced by filamentous fungi of the genusFusarium. Approximately one quarter of the world's food crops (mainly cereals) are affected by mycotoxins such as DON. A rapid and non-destructive method to evaluate the quality and safety of grains is therefore required to eliminate these toxins from the food chain. The first portable acoustic device that predicts the concentration of DON in cereal grains has been developed using a broadband capacitive ultrasonic transducer. An acoustic method was optimised for the rapid prediction of DON in wheat. To measure the performance of this method, a model system comprising 0-100% scabby wheat grains was prepared and a single laboratory validation was carried out. The best regression model between DON concentrations determined by the reference ELISA method and the acoustic technique was obtained at an acoustic frequency of 32.2 kHz, with a correlation coefficient of 0.9852 and a repeatability coefficient of variation of 2.1-9.3%, which is much better than the results achieved by prototype acoustic spectrometers. These data show that acoustic technology allows the online monitoring of DON in cereal grains, such as wheat, because it is possible to analyse multilayer grain beds. Sound absorption depends on the grain size and moisture content, so it is advisable to use the equipment at the point of harvest, where one strain of cereals usually dominates and the grains have a more homogeneous morphology and uniform moisture content.

Natural occurrence of fusarium head blight, mycotoxins and mycotoxin‐producing isolates of Fusarium in commercial fields of wheat in Hubei

Combined analyses of the natural occurrence of fusarium head blight (FHB), mycotoxins and mycotoxin‐producing isolates of Fusarium spp. in fields of wheat revealed FHB epidemics in 12 of 14 regions in Hubei in 2009. Mycotoxin contamination ranged from 0·59 to 15·28 μg g−1 in grains. Of the causal agents associated with symptoms of FHB, 84% were Fusarium asiaticum and 9·5% were Fusarium graminearum, while the remaining 6·5% were other Fusarium species. Genetic chemotyping demonstrated that F. asiaticum comprised deoxynivalenol (DON), 3‐acetyldeoxynivalenol (3‐AcDON), 15‐acetyldeoxynivalenol (15‐AcDON) and nivalenol (NIV) producers, whereas F. graminearum only included DON and 15‐AcDON producers. Compared with the chemotype patterns in 1999, there appeared to be a modest shift towards 3‐AcDON chemotypes in field populations during the following decade. However, isolates genetically chemotyped as 3‐AcDON were present in all regions, whereas the chemical 3‐AcDON was only detected in three of the 14 regions where 3‐AcDON accounted for 15–20% of the DON and acetylated forms. NIV mycotoxins were detected in seven regions, six of which also yielded NIV chemotypes. The number of genetic 3‐AcDON producers was positively correlated with amounts of total mycotoxins (DON, NIV and acetylated forms) or DON in wheat grains. Chemical analyses of wheat grains and rice cultures inoculated with different isolates from the fields confirmed their genetic chemotypes and revealed a preferential biosynthesis of 3‐AcDON and 4‐AcNIV in rice. These findings suggest the importance of chemotyping coupled with species identification for improved prediction of mycotoxin contamination in wheat.

Prediction model for deoxynivalenol in wheat grain based on weather conditions

Environmental factors influence the growth, survival, dissemination and hence the incidence of <i>Fusarium</i> fungi and the disease severity. The knowledge of the quantitative and qualitative effects of environmental factors and growing practices on initial infection, disease development and mycotoxin production is important for prediction of disease severity, yield impact and grain contamination with mycotoxins. The objective of this study was to design a model for prediction of deoxynivalenol (DON) content in winter wheat grain based on weather conditions, preceding crop and soil cultivation. The grain samples from winter wheat field experiments conducted in 2002–2005 to determine the effect of preceding crop in combination with soil cultivation on Fusarium head blight infection were analysed for the DON content. Average daily weather data (temperature, rainfall, relative humidity) were collected using an automated meteorological station and analysed separately for April, May and a 5 days period prior to the beginning of flowering and 5 days after the beginning of flowering. The correlation coefficients of DON content to weather data were calculated for monthly data prior to heading and 5 days data prior to and after the beginning of anthesis. Highest positive correlation coefficients were found for sum of precipitation in April, average temperature in April, and sum of precipitation 5 days prior to anthesis. Significant negative correlation was found for average temperature in May and average relative humidity 5 days prior to anthesis. Using the data from this experiment, we trained neural networks for prediction of deoxynivalenol content on the basis of weather data and preceding crop. The most appropriate neural network model was then coupled with AgriClim model to simulate spatial and temporal variation of DON content in wheat samples for south Moravia and north-east Austria area.

Agronomic considerations for reducing deoxynivalenol in wheat grain

Wheat fields under an array of agronomic practices were studied during harvest across southern and eastern Ontario. Mature wheat grain samples were harvested by hand and analyzed for deoxynivalenol (DON). DON levels from wheat grain samples harvested by hand were likely more representative of levels in the field than samples that are typically harvested by machine. The amount of variation in DON levels associated with year and agronomic effects were calculated from simple linear models. As expected, the largest factor associated with variation in DON levels was the year. Year effects accounted for 48% of the variation in DON levels across all fields during 4 years of the survey, followed by cultivar (27%), and the crop 1 year previous to wheat (14–28% depending on the year). No effect on DON could be detected from other agronomic factors including tillage system, crops planted 3 years before wheat, or type of nitrogen fertilizer applied in the spring.