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1.
Toxin B — trichothecene deoxynivalenol (DON) is the most frequent Fusarium mycotoxin in Fusarium head blight (FHB) disease produced by Fusarium fungi. Thirty-one samples of naturally cultivated winter wheat were collected from different localities in Slovakia and evaluated for DON content, and after an artificial inoculation twelve of winter wheat cultivars were evaluated for FHB, fusarium damaged kernels (FDK) and DON content (resistance Type I and II) during two years. Plants were inoculated at anthesis with a conidial suspension of Fusarium culmorum (W. G. Smith) Sacc. The highest mean contents of DON 1.641 ppm were found in produced potato region (PPR) and 1.654 ppm in produced sugar beet region (PSBR). A positive correlation was found between DON content and rainfall, and a negative correlation was found between content of DON and temperature. Lower positive correlations were found between the contents of DON in 2003 and 2004 in the resistance Type I and Type II in twelve artificially infected cultivars. The significant positive correlations in content of DON were found between resistance Type I and Type II in the years 2003 and 2004. The lowest content of DON was found in the cultivars Alka, Malyska and the highest one in the cultivars Vanda and Boka. The positive correlation between the content of DON and FDK (in %) in head (average 2003 and 2004 years) from artificially infected and analysed cultivars was statistically significant in both resistances Type I and Type II.  相似文献   

2.
A mycological survey was carried out on wheat heads from the main production area of Argentina. The isolation frequency and relative density of species from genus Fusarium and dematiaceous fungi were calculated. F graminearum was the predominant Fusarium species; similar to that observed in the USA and Canada. An analysis of deoxynivalenol (DON) natural contamination also was performed on a limited number (44) of samples. DON contamination levels in positive samples ranged from 0.2 to 30 ppm. A stepwise regression procedure showed that, among the species analysed, F. graminearum relative density was related to the DON contamination level and that other prevalent fungi did not influence or modify that relationship.  相似文献   

3.
Development of deoxynivalenol (DON) in wheat with a low contamination withFusarium spp. was investigated under suboptimal storage conditions (17% and 20% grain moisture, 20°C). The influence of storage on the relative DNA content of potential DON producers was also determined. The DON contents were quantified using an ELISA. The Tox5 PCR was used for the detection of potential trichothecene producers and for the estimation of their relative DNA content. ThegaoA gene was subsequently amplified by PCR to detect specificallyFusarium graminearum. The concentration ofF. graminearum DNA was semiquantitatively determined using a Light Cycler?. The DON concentrations increased during storage trials but the intensity of PCR signals decreased.  相似文献   

4.
With the focus on minimizingFusarium head blight and the deoxynivalenol (DON) contamination of wheat a three year crop rotation system starting with forage maize and followed by two years of winter wheat was combined with three soil tillage systems and selected plant varieties with varying susceptibility toFusarium infection. Higher DON concentrations were generally observed in wheat grain when the soil was mulched rather than ploughed, depending on the mass of maize residues remaining on the soil surface. Maize residues are the most important source ofFusarium inoculum. Infected maize residues had a main impact on the level of DON contamination in wheat grain particularly in the first year after maize cultivation. When the maize stubble was chopped before mulching, the decomposition of the residues was speeded up and the DON contamination of the wheat grain was lower. In the second year following the maize crop, the decomposition of the maize residues/Fusarium biomass was nearly complete and the infection risk was reduced considerably. An influence of the susceptibility of the maize variety against stem rot on the DON concentration of the succeeding winter wheat crop was not observed. The less susceptible wheat variety was suitable for controlling the higher infection risk deriving from the introduction of maize in wheat rotation and the use of mulching techniques. Presented at the 28th Mykotoxin-Workshop, Bydgoszcz, Poland, May 29–31, 2006  相似文献   

5.
Wheat seed samples with different initial infection levels of Fusarium culmorum were kept under different storage conditions for 36 weeks. Samples for analysis were drawn before storage and at intervals of 6‐8 weeks to determine the mycotoxin contents, seed health and seed quality. Zearalcnone (ZEA) accumulated to higher kernel contents towards the end of storage, when the seed was stored under warm and humid conditions [25°C/90% relative humidity (RH)], whereas the deoxynivalenol (DON) content of severely infected kernel samples (> 50%) remained unchanged under any of the conditions. On the other hand, DON contents increased in samples with a slight (4%) or moderate (15%) Fusarium infection level. when the seed was stored under Warm and humid conditions. Nivalenol (NIV) was not found in any samples immediately after harvest but later on in storage, and only under cool or warm but very humid conditions (15°C/84% RH and 25°C/90% RH). During storage, the mycotoxin contents of the samples did not reflect the percentage of Fusarium infected kernels. Under warm but dry conditions (25°C/62% RH) the seed germination rate showed a slight increase or remained nearly constant; at the same time the Fusarium infection level of the kernels decreased fairly fast. Cool and dry conditions (15°C/56% RH) maintained good seed quality but the Fusarium infection level of the kernels remained largely the same. Warm and humid conditions are not appropriate to maintaining quality of both seed and grain product.  相似文献   

6.
At anthesis, under field conditions at Fundulea, each of 6 Romanian winter wheat genotypes was inoculated with 3Fusarium graminearum isolates used individually.Fusarium head blight (FHB) was assessed according to the following traits: relative weight of spikes (RWS), percentage of Fusarium damaged kernels (FDK), relative weight of kernels per head (RWKH), area under the disease progress curve (AUDPC) and deoxynivalenol (DON) content in total sample of kernels. Correlations between these traits and parameters revealed important differences between examined wheat genotypes in: DON accumulation, progress of FHB development, yield reduction, and models of host — pathogen interactions in theTriticum - Fusarium pathosystem. Significant correlations between different attributes of FHB were found forFusarium isolate 1 which is a moderate producer of DON (0.89 μg g-1). Weight of spike was significantly correlated with weight of kernels per spike (r = 0.93**) and with percentage of damaged kernels (r = - 0.87**), while FDK was highly correlated with RWKH (r = - 0.85*) and with DON content (r = 0.82*). Area under the disease progress curve was also found to be significantly correlated with DON content (r = 0.86*).  相似文献   

7.
Wheat for human consumption (140 samples) was collected after harvest from all regions of Bulgaria. The 1995 crop year was characterized by heavy rainfall in the spring and summer months. The internal mycoflora of wheat samples was dominated by Fusarium spp. and Alternaria spp., and storage fungi were rarely present. The samples were analysed for contamination with Fusarium mycotoxins deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), T-2 Toxin (T-2), diacetoxyscirpenol (DAS), and zearalenone (ZEA), using enzyme immunoassay methods. DON and ZEA were the predominant toxins, with a contamination frequency of 67% and 69%, respectively. The average levels of these toxins in positive samples were 180 g/kg (DON) and 17 g/kg (ZEA), maximum concentrations were 1800 g kg–1 and 120 g kg–1, respectively. Acetyl derivatives of DON, namely 3-AcDON and 15-AcDON, were found in 2.1 % and 0.7% of the samples, at at maximum level of about 100 g kg–1. Only one sample was positive for T-2 (55 g/kg), DAS was not detected. This is the first report about the natural occurrence of a range of Fusarium mycotoxins in wheat for human consumption in Bulgaria.Abbreviations 3-AcDON 3-acetyldeoxynivalenol - 15-AcDON 15-acetyldeoxynivalenol - DAS diacetoxyscirpenol - DON deoxynivalenol - EIA enzyme immunoassay - T-2 T-2 toxin - ZEA zearalenone  相似文献   

8.
This investigation aimed at the progression of the contamination of theFusarium toxins deoxynivalenol (DON) and zearalenone (ZON) within the fractions straw, glumes and spindles from non-inoculated andFusarium-inoculated wheat. TheFusarium head blight (FHB)-susceptible wheat cultivar Ritmo was cultivated after the pre-crop maize and artificially infected withFusarium culmorum. Samples of whole wheat plants were taken once a week from anthesis until harvest and fractionated into straw, glumes and spindles. Samples were examined for deoxynivalenol and zearalenone and quantitatively determined by high performance liquid chromatography (HPLC) with diode-array detection (DAD) and fluorescence detection, respectively. Additionally, the impact of theFusarium inoculation on the crude protein content was scrutinised. Differences in the formation of deoxynivalenol and zearalenone with respect to date and concentration are shown by this trial. Deoxynivalenol was produced in higher concentrations and at earlier stages, whereas zearalenone was formed later and in smaller amounts. Furthermore, a rise of the deoxynivalenol concentration up to a maximum during the growing season, followed by a sudden decline at later stages until harvest, was observed. ThisFusarium infection resulted in an increased crude protein content in all of the three fractions.  相似文献   

9.
The correlation between the amount of deoxynivalenol (DON) and the percentage ofFusarium damaged kernels (FDK) in samples of wheat and triticale was studied.Samples of naturally infected wheat grain, collected in 1986, 1987 and 1988 and of triticale collected in 1986 were used.Additionally, artificial inoculated wheat samples (10 genotypes inoculated with 3F. Culmorum strains of weak, medium and severe pathogenicity and samples of 10 triticale genotypes inoculated withF. culmorum. andF. graminearun) were studied. Using statistical methods (the variance analysis, method of least significant difference (LSD), orthogonal contrast (OC) and minimum within groups sum of squares criterion (MSSC)), the samples were divided into two groups with respect to the attribute DON/FDK.To the first group belong samples of wheat and triticale, of which the heads were artificially inoculated with severely pathogenic strainsF. culmorum. In the samples of this group the amount of DON in kernels damaged withFusarium increased by 0,46 mg/kg per 1% of FDK.In the second group, consisting of naturally infected samples and samples from artificially inoculated heads the amount of DON increased 0,30 mg DON/kg per 1% of FDK.The equation for the calculation of approximated amount of DON in farm and commercial lots of wheat and triticale after examination of percentage of FDK is given.  相似文献   

10.
Deoxynivalenol (DON) is the major mycotoxin produced by Fusarium fungi in grains. Food and feed contaminated with DON pose a health risk to humans and livestock. The risk can be reduced by enzymatic detoxification. Complete mineralization of DON by microbial cultures has rarely been observed and the activities turned out to be unstable. The detoxification of DON by reactions targeting its epoxide group or hydroxyl on carbon 3 is more feasible. Microbial strains that de-epoxidize DON under anaerobic conditions have been isolated from animal digestive system. Feed additives claimed to de-epoxidize trichothecenes enzymatically are on the market but their efficacy has been disputed. A new detoxification pathway leading to 3-oxo-DON and 3-epi-DON was discovered in taxonomically unrelated soil bacteria from three continents; the enzymes involved remain to be identified. Arabidopsis, tobacco, wheat, barley, and rice were engineered to acetylate DON on carbon 3. In wheat expressing DON acetylation activity, the increase in resistance against Fusarium head blight was only moderate. The Tri101 gene from Fusarium sporotrichioides was used; Fusarium graminearum enzyme which possesses higher activity towards DON would presumably be a better choice. Glycosylation of trichothecenes occurs in plants, contributing to the resistance of wheat to F. graminearum infection. Marker-assisted selection based on the trichothecene-3-O-glucosyltransferase gene can be used in breeding for resistance. Fungal acetyltransferases and plant glucosyltransferases targeting carbon 3 of trichothecenes remain promising candidates for engineering resistance against Fusarium head blight. Bacterial enzymes catalyzing oxidation, epimerization, and less likely de-epoxidation of DON may extend this list in future.  相似文献   

11.
Field response of wheat to arbuscular mycorrhizal fungi and drought stress   总被引:3,自引:0,他引:3  
Al-Karaki G  McMichael B  Zak J 《Mycorrhiza》2004,14(4):263-269
Mycorrhizal plants often have greater tolerance to drought than nonmycorrhizal plants. This study was conducted to determine the effects of arbuscular mycorrhizal (AM) fungi inoculation on growth, grain yield and mineral acquisition of two winter wheat (Triticum aestivum L.) cultivars grown in the field under well-watered and water-stressed conditions. Wheat seeds were planted in furrows after treatment with or without the AM fungi Glomus mosseae or G. etunicatum. Roots were sampled at four growth stages (leaf, tillering, heading and grain-filling) to quantify AM fungi. There was negligible AM fungi colonization during winter months following seeding (leaf sampling in February), when soil temperature was low. During the spring, AM fungi colonization increased gradually. Mycorrhizal colonization was higher in well-watered plants colonized with AM fungi isolates than water-stressed plants. Plants inoculated with G. etunicatum generally had higher colonization than plants colonized with G. mosseae under both soil moisture conditions. Biomass and grain yields were higher in mycorrhizal than nonmycorrhizal plots irrespective of soil moisture, and G. etunicatum inoculated plants generally had higher biomass and grain yields than those colonized by G. mosseae under either soil moisture condition. The mycorrhizal plants had higher shoot P and Fe concentrations than nonmycorrhizal plants at all samplings regardless of soil moisture conditions. The improved growth, yield and nutrient uptake in wheat plants reported here demonstrate the potential of mycorrhizal inoculation to reduce the effects of drought stress on wheat grown under field conditions in semiarid areas of the world.  相似文献   

12.
Ayurvedic medicine, which uses decoctions made of medicinal plants, is used to cure diseases in many Asian countries including Sri Lanka. Although proper storage facilities for medicinal plants are unavailable in Sri Lanka, neither the potential for growth of toxigenic fungi nor their ability to produce mycotoxins in stored medicinal plants has been investigated. We isolated three Fusarium species, F. culmorum, F. acuminatum and F. graminearum from the medicinal plant Tribulus terrestris. Culture extracts of the 3 Fusarium spp. were cytotoxic to mammalian cell lines BHK-21 and HEP-2. Three toxic metabolites produced by Fusarium spp; T-2 toxin, zearalenone, and diacetoxyscirpenol were also cytotoxic to the same mammalian cell lines. The 3 Fusarium spp. grown on rice media produced zearalenone. Plant material destined for medicinal use should be stored under suitable conditions to prevent growth of naturally occurring toxigenic fungi prior to its use.  相似文献   

13.
From 1999?–?2001 three different varieties of wheat [Contur (susceptible to Fusarium), Batis and Petrus (less susceptible to Fusarium)] were cultivated under organic and conventional conditions in order to determine mycotoxin burden. Soil quality, preceding crop and weather conditions were comparable in the different production systems. The wheat batches were analysed for moulds, and the contents of zearalenone (ZEN) and deoxynivalenol (DON). Feeding trials were carried out with growing pigs (n?=?96; average initial live weight 22.2 ±?1.5?kg [mean?±?SD]) to examine a possible influence on the animal performance and on mycotoxin residues. The data recorded were clinical conditions, performance, biochemical and hematological data. Residues of ZEN, α- and β-zearalenol (ZEL) and of DON were determined in bile, liver and muscle after slaughtering. Conventionally cultivated wheat was more frequently contaminated with Fusarium and contained more frequently ZEN and DON in higher concentrations than the organically produced wheat. Hematological and biochemical parameters of pigs fed with organically cultivated diets were not different from those of conventionally fed pigs. Pigs fed with organically produced wheat showed a slightly higher daily weight gain, but a lower carcass yield than the conventionally fed animals. The highest residues of DON and total-ZEN (ZEN + α-ZEL + β-ZEL) were found in bile. Bile samples of organically fed pigs contained lower concentrations of total-ZEN than those of conventionally fed pigs. Altogether, these data suggest that wheat from an organic farming does not have higher mycotoxin-contamination than wheat from the conventional farming system.  相似文献   

14.
Plant pathogenic fungi of the genus Fusarium can cause severe diseases on small grain cereals and maize. The contamination of harvested grain with Fusarium mycotoxins is a threat to human and animal health. In wheat production of the toxin deoxynivalenol (DON), which inhibits eukaryotic protein biosynthesis, is a virulence factor of Fusarium, and resistance against DON is considered to be part of Fusarium resistance. Previously, single amino acid changes in RPL3 (ribosomal protein L3) conferring DON resistance have been described in yeast. The goal of this work was to characterize the RPL3 gene family from wheat and to investigate the potential role of naturally existing RPL3 alleles in DON resistance by comparing Fusarium-resistant and susceptible cultivars. The gene family consists of three homoeologous alleles of both RPL3A and RPL3B, which are located on chromosomes 4A (RPL3-B2), 4B (RPL3-B1), 4D (RPL3-B3), 5A (RPL3-A3), 5B (RPL3-A2) and 5D (RPL3-A1). Alternative splicing was detected in the TaRPL3-A2 gene. Sequence comparison revealed no amino acid differences between cultivars differing in Fusarium resistance. While using developed SNP markers we nevertheless found that one of the genes, namely, TaRPL3-A3 mapped close to a Fusarium resistance QTL (Qfhs.ifa-5A). The potential role of the RPL3 gene family in DON resistance of wheat is discussed.  相似文献   

15.
The aim of the study was to examine the effects of dry matter intake level and the feeding ofFusarium-contaminated wheat on the toxin-turnover and ruminal fermentation of dairy cows. Fourteen dairy cows equipped with ruminal and duodenal cannulae were used. All animals were fed the same diet, only the daily feed amounts were adjusted to the current performance stage of the cow. On a dry matter basis, the diet consisted of 60% concentrate including 55% wheat (Fusarium-contaminated wheat [Mycotoxin period] or control wheat [Control period]). Each cow was fed with both the contaminated and the control wheat. TheFusarium-contamination of the wheat significantly decreased the flow of undegraded protein at the duodenum with increased intakes of organic matter. The duodenal flow of microbial protein and the activities of aspartate aminotransferase (ASAT), glutamate dehydrogenase (GLDH) and gamma glutamyl transferase (γ-GT) in the serum were not affected by dietary treatment, but increased with feed intake. The duodenal flow of deoxynivalenol (DON) and de-epoxy DON related to DON intake ranged between 12 and 77% when theFusarium-contaminated wheat was fed. DON was almost completely metabolized to de-epoxy DON independent of the feed intake level. The zearalenone (ZON) flow at the duodenum increased moderately with increasing ZON/feed intake.  相似文献   

16.
Wheat infected naturally withFusarium, contaminated mainly with 18.53 mg DON per kg, was added to a total constant wheat proportion of 400g/kg diet. Control and DON contaminated feed was fed for 11 weeks underad libitum and restrictive feeding conditions to 48 pigs of both sexes, which were randomly divided into 4 groups. Effects on performance (live weight range between 26 and 100kg), duration of feed intake and blood parameters were investigated. Parallel to this study, a balance study was carried out to examine the effects on nutrient digestibility and DON metabolism. The group fed the DON contaminated rationad libitum consumed 15% less feed and gained 14% less live weight compared to thead libitum control group, while the feed to gain ratio was unaffected. Under restrictive feeding conditions (DON and control) pigs exhibited 33%, 25% and 10% lower feed consumption, live weight gain and feed to gain ratio, respectively, than the control group fedad libitum. Metabolizability of energy, digestibility of organic matter, crude protein, crude fat and N-retention were significantly increased by 4, 3, 6, 11 and 10%, respectively, in the DON group of the restrictively fed pigs. In average up to 43.2% of the ingested DON, as the parent toxin in both groups, was eliminated with the urine and up to 3.0% with faeces. DON fed animals needed more time to consume the restrictive ration than the control group. Presented at the 26th Mykotoxin-Workshop in Herrsching, Germany, May 17–19, 2004. Financial support Deutsone Forschungsgemeingschaft  相似文献   

17.
Conservation tillage combined with crop-residue mulching is increasingly important to meet soil protection targets. Concurrently, the health risk of soil-borne pathogenic fungi like Fusarium species, which produce deoxynivalenol (DON) as their major mycotoxin, is increasing. The detritivorous earthworm species Lumbricus terrestris takes part in the efficient degradation of Fusarium-infected and DON-contaminated wheat straw. Against this background, a laboratory study was conducted to quantify by means of ELISA technique the uptake of DON and its possible absorption and accumulation in tissue by L. terrestris in the short-term (5 weeks) and long-term (11 weeks). The DON concentrations in L. terrestris of the Fusarium-infected treatment were significantly different in the order of gut tissue > body wall > gut content at both dates with a decline in the long-term. The DON concentrations in the tissues decreased by an order of magnitude of weeks to months.  相似文献   

18.
The concentrations of the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) of a heavily contaminated wheat grain batch were followed over a period of 1 year by taking samples 15 times every 28 days. The air temperature and relative humidity at the top of the wheat batch ranged between 7 and 22°C and 44 and 55%, respectively, and corresponded to a variation in the moisture content of the wheat grain between 11.5 and 12.3%. None of these fluctuations were related to ZON and DON concentrations, which varied between 0.46 and 0.66 and 15.0 and 19.5 mg/kg DM. Therefore, the data were used to analyse the error sources for the analytical results. It was found that the variance proportions due to sampling and sample preparation plus analysis were not similar for DON and ZON. The variance proportion due to sampling was found to be 0.62 for ZON, which corresponded to a variance proportion of 0.38 due to sample preparation plus analysis. In contrast, the latter variance proportion for DON was estimated to be 1.0 and consequently completely superimposed the sampling error. It is concluded that long-term storage of contaminated wheat grain does not affect the concentrations of DON and ZON considering the measured fluctuations in ambient temperature, relative humidity and moisture content of the grain. Therefore, no degradation of DON and ZON occurred during the storage of wheat for a period of one year under ambient conditions. The effects of sampling and sample preparation plus analysis on the final analytical results are different for DON and ZON and require further consideration.  相似文献   

19.
Winter wheat cultivar Basalt was artificially inoculated with Fusarium culmorum at the end of anthesis and treated with the systemic fungicide tebuconazole (Folicur®) a few days before and/or after inoculation. Check plots remained uninoculated and unsprayed. Head infections, yield, yield components and the percentage of Fusarium‐ infected kernels were determined. Artificial Fusarium inoculation lowered yield significantly by 24.2‐45.0%. Any fungicide treatment saved yield, thousand grain weight and kernel numbers per head. Pre‐infectional application of tebuconazole was superior to application carried out post‐infection. Moreover, the fungicide controlled deoxynivalenol (DON) synthesis in the field to a considerable extent, and enabled good control of Fusarium head blight, glume blotch and the percentage of Fusarium‐infected kernels. The levels of Fusarium kernel infection after harvest clearly reflected the DON content of w heat grain.  相似文献   

20.
The Fusarium diversity and the mycobiota associated with moldy wheat kernels from Santa Fe province, Argentine, was assessed. The wheat cultivated area in Santa Fe province is divided according to agrometeorological conditions into two zones: Zone I (north-central) and Zone II (south). The natural occurrence of Fusarium toxins BEA, FUP, DON and NIV was also determined. Cladosporium was the most abundant of the 19 genera identified, followed by Fusarium, Phoma and Alternaria. Zone II shows a predominance of F. graminearum and F. culmorum. In Zone I, DON was present in 13/32 samples (range 0.43–3.60 mg kg−1) and NIV in 6/32 samples (range 0.11–0.40 mg kg−1). In zone II, DON was found in 11/21 samples (range 0.57–9.50 mg kg−1) and NIV in 4/21 samples (range 0.10–0.60 mg kg−1). BEA and FP were not detected in both zones.  相似文献   

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