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Key message: Fine mapping and sequencing revealed 28 genes in the non-recombining haplotype containing Fhb1 . Of these, only a GDSL lipase gene shows a pathogen-dependent expression pattern. Abstract: Fhb1 is a prominent Fusarium head blight resistance locus of wheat, which has been successfully introgressed in adapted breeding material, where it confers a significant increase in overall resistance to the causal pathogen Fusarium graminearum and the fungal virulence factor and mycotoxin deoxynivalenol. The Fhb1 region has been resolved for the susceptible wheat reference genotype Chinese Spring, yet the causal gene itself has not been identified in resistant cultivars. Here, we report the establishment of a 1 Mb contig embracing Fhb1 in the donor line CM-82036. Sequencing revealed that the region of Fhb1 deviates from the Chinese Spring reference in DNA size and gene content, which explains the repressed recombination at the locus in the performed fine mapping. Differences in genes expression between near-isogenic lines segregating for Fhb1 challenged with F. graminearum or treated with mock were investigated in a time-course experiment by RNA sequencing. Several candidate genes were identified, including a pathogen-responsive GDSL lipase absent in susceptible lines. The sequence of the Fhb1 region, the resulting list of candidate genes, and near-diagnostic KASP markers for Fhb1 constitute a valuable resource for breeding and further studies aiming to identify the gene(s) responsible for F. graminearum and deoxynivalenol resistance. [ABSTRACT FROM AUTHOR]

Key message: Markers closely flanking a Type 1 FHB resistance have been produced and the potential of combining this with Type 2 resistances to improve control of FHB has been demonstrated. Abstract: Two categories of resistance to Fusarium head blight (FHB) in wheat are generally recognised: resistance to initial infection (Type 1) and resistance to spread within the head (Type 2). While numerous sources of Type 2 resistance have been reported, relatively fewer Type 1 resistances have been characterised. Previous study identified a Type 1 FHB resistance ( QFhs.jic- 4AS) on chromosome 4A in Triticum macha. Little is known about the effect of combining Type 1 and Type 2 resistances on overall FHB symptoms or accumulation of the mycotoxin deoxynivalenol (DON). QFhs.jic- 4AS was combined independently with two Type 2 FHB resistances ( Fhb1 and one associated with the 1BL/1RS translocation). While combining Type 1 and Type 2 resistances generally reduced visual symptom development, the effect on DON accumulation was marginal. A lack of polymorphic markers and a limited number of recombinants had originally prevented accurate mapping of the QFhs.jic- 4AS resistance. Using an array of recently produced markers in combination with new populations, the position of QFhs.jic- 4AS has been determined to allow this resistance to be followed in breeding programmes. [ABSTRACT FROM AUTHOR]

Fusarium graminearum is a common agent causing Fusarium head blight (FHB) on wheat throughout the world. Aggressiveness is crucial for understanding the interaction between host-pathogen in the FHB-wheat system. In this paper, we modified and validated the Petri-dish test originally described by Mesterhazy (Phytopathologische Zeitschrift 93:12-25, ) to quantify the aggressiveness of 25 F. graminearum strains using four durum wheat cultivars with different resistance levels for FHB. The results were highly significant and correlated with those obtained using adult plants in the growth chamber and in the field ( r = 0.94, P < 0.001 and r = 0.65, P < 0.001, respectively). The Petri-dish test was further investigated for its repeatability and stability in different durum wheat cultivars and highly significant correlation coefficients were obtained ( r = 0.90-0.91 ( P < 0.001), 0.89-0.95 ( P < 0.001), respectively). In this study, we also demonstrated that germination rate reduction and coleoptile length reduction are parameters involved with aggressiveness of F. graminearum. The mean of three disease parameters from the modified Petri-dish method is introduced in this paper as a new parameter for aggressiveness and named 'Petri-dish aggressiveness index'. The results obtained reveal that this modified Petri-dish test is rapid, reliable and stable with different durum wheat cultivars, and yields highly significant correlation coefficients with floret and ear inoculations, thus it is suitable to be used for quantification of aggressiveness of F. graminearum. [ABSTRACT FROM AUTHOR]

Breeding for fusarium head blight (FHB) resistance of wheat is a continuous challenge for plant breeders. Resistance to FHB is a quantitative trait, governed by several to many genes and modulated by environmental conditions. The presented study was undertaken to assess the effect on improving FHB resistance and on possible unwanted side effects ('linkage drag') of two resistance QTL, namely Fhb1 and Qfhs.ifa- 5A, from the spring wheat line CM-82036 when transferred by marker-assisted backcrossing into several European winter wheat lines. To achieve these goals, we developed and evaluated fifteen backcross-two-derived families based on nine European winter wheat varieties as recipients and the FHB resistant variety CM-82036 as resistance donor. The QTL Qfhs.ifa- 5A had a relatively small impact on increasing FHB resistance. On average lines with Fhb1 plus Qfhs.ifa- 5A combined were only slightly more resistant compared to lines with Fhb1 alone. The obtained results suggest that the effect of the spring wheat-derived QTL on improving FHB resistance increases in the order Qfhs.ifa- 5A < Fhb1 ≤ Qfhs.ifa- 5A plus Fhb1 combined. The genetic background of the recipient line had a large impact on the resistance level of the obtained lines. No systematic negative effect of the spring wheat-derived QTL on grain yield, thousand grain weight, hectoliter weight and protein content was found. The use of spring wheat-derived FHB resistance QTL for breeding high yielding cultivars with improved FHB resistance appears therefore highly promising. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) of wheat has become a serious threat to wheat crops in numerous countries. In addition to loss of yield and quality, this disease is of primary importance because of the contamination of grain with mycotoxins such as deoxynivalenol (DON). The Swiss winter cultivar Arina possesses significant resistance to FHB. The objective of this study was to map quantitative trait loci (QTL) for resistance to FHB, DON accumulation and associated traits in grain in a double haploid (DH) population from a cross between Arina and the FHB susceptible UK variety Riband. FHB resistance was assessed in five trials across different years and locations. Ten QTL for resistance to FHB or associated traits were detected across the trials, with QTL derived from both parents. Very few of the QTL detected in this study were coincident with those reported by authors of two other studies of FHB resistance in Arina. It is concluded that the FHB resistance of Arina, like that of the other European winter wheat varieties studied to date, is conferred by several genes of moderate effect making it difficult to exploit in marker-assisted selection breeding programmes. The most significant and stable QTL for FHB resistance was on chromosome 4D and co-localised with the Rht–D1 locus for height. This association appears to be due to linkage of deleterious genes to the Rht-D1b ( Rht2) semi-dwarfing allele rather than differences in height per se. This association may compromise efforts to enhance FHB resistance in breeding programmes using germplasm containing this allele. [ABSTRACT FROM AUTHOR]

Plants have a high capacity to transform and thereby detoxify deleterious or poisonous compounds, like mycotoxins. The formation of glucose conjugates has a central role in this process. Mammals, however, are able to (partly) release the precursor substances during digestion, reactivating the mycotoxins. This short review provides a brief summary about the metabolism of the Fusarium mycotoxins deoxynivalenol and zearalenone in plants. Two examples are discussed in greater detail. First, the formation of deoxynivalenol-3-glucoside in wheat is linked to a quantitative trait locus that is often used for Fusarium head blight resistance breeding. Secondly, the metabolism of zearalenone in Arabidopsis thaliana results in at least 17 different metabolites, all of which are potentially hazardous for humans and animals. [ABSTRACT FROM AUTHOR]

Naturally contaminated and artificially Fusarium spp. inoculated wheat was analyzed for deoxynivalenol, deoxynivalenol-3-glucoside, 3-acetyl-deoxynivalenol and 15-acetyl-deoxynivalenol. After extraction and clean-up with MycoSep columns, the trichothecenes were determined using a LC-ESI-MS/MS method. Deoxynivalenol-3-glucoside was detectable in 4 out of 4 artificially inoculated and in 22 out of 25 naturally contaminated wheat samples. For the latter, the average relative deoxynivalenol-3-glucoside concentration was about 6% of the deoxynivalenol concentration. The maximum relative deoxynivalenol-3-glucoside concentration was 12% as compared to the concentration of deoxynivalenol. In all samples, the concentration of deoxynivalenol-3-glucoside was higher than the concentrations of 3-acetyl-deoxynivalenol or 15-acetyl-deoxynivalenol. [ABSTRACT FROM AUTHOR]

DON-3ß-glucopyranoside was synthesized and characterized by LC-MS/MS. The formation of by-products in the chemical synthesis was further evaluated and, according to their different fragmentation behaviours, it was possible to postulate their structures. The occurrence of these substances in nature was investigated by the analysis of wheat ears, which were treated with DON at anthesis. For the first time DON-3-glucoside could be detected in wheat, strongly indicating that it could also occur in naturally contaminated cereals. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) is a destructive disease of wheat. The objective of this study was to characterise the FHB resistance of the Brazilian spring wheat cultivar Frontana through molecular mapping. A population of 210 doubled-haploid lines from a cross of Frontana (partially resistant) and Remus (susceptible) was evaluated for FHB resistance during three seasons. Spray and single-spikelet inoculations were applied. The severity, incidence and spread of the disease were assessed by visual scoring. The population was genotyped with 566 DNA markers. The major QTL effect associated with FHB resistance mapped to chromosome 3A near the centromere, explaining 16% of the phenotypic variation for disease severity over 3 years. The most likely position is in the Xgwm720–Xdupw227 interval. The genomic region on 3A was significantly associated with FHB severity and incidence in all years evaluated, but not with FHB spread, indicating the prominent contribution of this QTL to resistance against initial infection. The map interval Xgwm129–Xbarc197 on chromosome 5A also showed consistent association with FHB severity and accounted for 9% of the phenotypic variation. In addition, smaller effects for FHB severity were identified on chromosomes 1B, 2A, 2B, 4B, 5A and 6B in single years. Individual QTLs for resistance to FHB spread accounted for less than 10% of the variation in trait expression. The present study indicates that FHB resistance of Frontana primarily inhibits fungal penetration (type I resistance), but has a minor effect on fungal spread after infection (type II resistance). [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB) is a fungal disease of barley and other cereals, causing substantial yield and quality losses, mainly due to the contamination of the harvest with mycotoxins. We aimed to evaluate genetic variation for resistance to FHB and its association with other plant characters in diverse barley germplasm in order to identify useful lines for resistance breeding. The 143 barley lines consisted of 88 current European spring barley lines and cultivars, 33 accessions from the genebank at IPK Gatersleben, and 22 lines obtained from North American institutions. We conducted artificially inoculated field experiments with Fusarium graminearum Schwabe during two seasons. FHB severity was evaluated by repeated assessment of visual symptoms. On a set of 49 lines several trichothecene mycotoxins were analyzed. Variation for FHB severity was quantitative. The lines with lowest FHB severity were ‘CIho 4196’ and ‘PI 566203’. Also within the European spring barley collection variation for FHB severity was highly significant. There was a significant negative correlation between plant height and FHB severity (r = - 0.55). FHB severity assessed in the field and the amount of deoxynivalenol in the harvested grains were positively correlated (r = 0.87). Several lines with a useful level of FHB resistance were found or confirmed and are recommended as crossing partners. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB, scab) causes severe yield and quality losses, but the most serious concern is the mycotoxin contamination of cereal food and feed. The cultivation of resistant varieties may contribute to integrated control of this fungal disease. Breeding for FHB resistance by conventional selection is feasible, but tedious and expensive. The aim of this work was to detect QTLs for combined type I and type II resistance against FHB and estimate their effects in comparison to the QTLs identified previously for type II resistance. A population of 364, F1 derived doubled-haploid (DH) lines from the cross 'CM-82036' (resistant)/'Remus' (susceptible) was evaluated for components of FHB resistance during 2 years under field conditions. Plants were inoculated at anthesis with a conidial suspension of Fusarium graminearum or Fusarium culmorum. The crop was kept wet for 20 h after inoculation by mist-irrigation. Disease severity was assessed by visual scoring. Initial QTL analysis was performed on 239 randomly chosen DH lines and extended to 361 lines for putative QTL regions. Different marker types were applied, with an emphasis on PCR markers. Analysis of variance, as well as simple and composite interval mapping, revealed that two genomic regions were significantly associated with FHB resistance. The two QTLs on chromosomes 3B (Qfhs.ndsu-3BS) and 5A (Qfhs.ifa-5A) explained 29 and 20% of the phenotypic variance, respectively, for visual FHB severity. Qfhs.ndsu-3BS appeared to be associated mainly with resistance to fungal spread, and Qfhs.ifa-5A primarily with resistance to fungal penetration. Both QTL regions were tagged with flanking SSR markers. These results indicate that FHB resistance was under the control of two major QTLs operating together with unknown numbers of minor genes. Marker-assisted selection for these two major QTLs appears feasible and should accelerate the development of resistant and locally adapted wheat cultivars. [ABSTRACT FROM AUTHOR]

In two broiler and two turkey trials the influence of Fusarium toxins in maize on growth and slaughter performance, on residues of toxins in carcass and litters and blood parameters were investigated. In one broiler and turkey trial with naturally contaminated maize the main contaminants were deoxynivalenol (DON), moniliformin (MON and beauvericin (BEA). In one further broiler and turkey trial with inoculated maize (Fusarium subglutinans) the main contaminants were MON and BEA. The level of contamination of mycotoxins in the diets was free, low, medium and high. For every broiler trial 180 and for the turkey trials 60 and 100 one day old chicken were used. The result of these investigations shows that broiler and turkeys are not very sensitive to Fusarium toxins. Growth and slaughter performance and also blood parameters were not negative influenced by higher mycotoxin dosages in the diets. [ABSTRACT FROM AUTHOR]

Infection with Fusarium graminearum and F. culmorum not only causes severe yield and quality losses, the most relevant concern is the contamination of cereal foods and feeds with trichothecenes (e.g. deoxynivalenol, DON). The ability to synthesize trichothecenes has been shown to be a virulence factor of F. graminearum on wheat and, on the other hand, toxin resistance is most likely an important component of field resistance. Our hypothesis is that pleiotropic drug resistance mediated by PDR-type ABC transporter proteins (acting as membrane located drug efflux pumps) is a relevant mechanism of DON resistance not only in yeast but also in wheat. Goal of this project is the development of molecular markers for this gene family for use in marker-assisted plant breeding programs. The technical difficulties caused by the large size of the PDR-family are discussed. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB, scab) is a fungal disease of wheat and other small cereals that is found in both temperate and semi-tropical regions. FHB causes severe yield and quality losses, but the most-serious concern is the possible mycotoxin contamination of cereal food and feed. Breeding for FHB resistance by conventional selection is feasible, but tedious and expensive. This study was conducted to identify and map DNA markers associated with FHB resistance genes in wheat. A population of 364 F1-derived doubled-haploid (DH) lines from the cross ’CM-82036’ (resistant)/’Remus’ (susceptible) was evaluated for Type II resistance (spread within the spike) during 2 years under field conditions. Marker analysis was performed on 239 randomly chosen DH lines. Different marker types were applied, with an emphasis on AFLP and SSR markers. Analysis of variance, as well as simple and composite interval mapping, were applied. Three genomic regions were found significantly associated with FHB resistance. The most-prominent effect was detected on the short arm of chromosome 3B, explaining up to 60% of the phenotypic variance for Type II FHB resistance. A further QTL was located on chromosome 5A and a third one on 1B. The QTL regions on 3B and 5A were tagged with flanking SSR markers, the 1B QTL was found associated with the high-molecular-weight glutenin locus. These results indicate that FHB resistance is under control of a few major QTLs operating together with unknown numbers of minor genes. Marker-assisted selection for these major QTLs involved in FHB resistance appears feasible and should accelerate the development of resistant and agronomically improved wheat cultivars. [ABSTRACT FROM AUTHOR]

The electromechanical and -physiological effects of beauvericin were studied in isolated smooth and heart muscle preparations of the guinea pig. Beauvericin concentration-dependently decreased the force of contraction in precontracted (60 mM KCl) terminal ilea with an IC50 of 0.86 μM, and in electrically stimulated (1 Hz) papillary muscles with an IC50 of 18 μM. This negative inotropic effect in papillary muscles was antagonised in a non-competitive way by increased extracellular calcium concentrations. Spontaneous activity in right atria was affected at concentrations >10 μM beauvericin. The negative chronotropic effect was less pronounced than the negative inotropic effect. In action potentials of electrically driven (1 Hz) papillary muscles, 10 μM beauvericin significantly decreased membrane resting potential until unexcitability of the preparation occurred. Despite depolarisation of the membrane the maximum rate of rise of the action potential was not changed. The action potential duration was shortened, but the decrease was only significant at times to 20% and 50% repolarisation. These data, derived from the electrophysiological experiments, not only imply an effect on the calcium current as suggested by the effects on contractility, but also an interaction with the sodium inward and potassium outward currents. [ABSTRACT FROM AUTHOR]

Austrian isolates of Fusarium subglutinans and Fusarium proliferatum were studied for their ability to produce beauvericin, moniliformin and fumonisin B1 and B2 under laboratory conditions. Analytical methodology for beauvericin was specially adapted for this task. Our analyses showed that the strains produced beauvericin up to 687 mg /kg maize and moniliformin up to 70 mg/kg. The culture of F. proliferatum in addition produced fumonisin B1 and B2 at levels of 106 and 61 mg/kg, respectively. The preliminary toxicity experiments performed in this study clearly indicated a toxic effect of beauvericin on the contractility of mammalian smooth muscle and thus on mammalian cells. [ABSTRACT FROM AUTHOR]

Fusarium head blight (FHB or scab) caused by Fusarium spp. is a widespread disease of cereals causing yield and quality losses and contaminating cereal products with mycotoxins. The breeding of resistant varieties is the method of choice for controlling the disease. Unfortunately, the genetic basis of scab resistance is still poorly understood. We present the results of a back-cross reciprocal monosomic analysis of FHB resistance using the highly resistant Hungarian winter wheat line ‘U-136.1’ and the highly susceptible cultivar ‘Hobbit-sib’. Resistance testing was performed in a field trial artificially inoculated with a Fusarium culmorum conidial suspension. Five hemizygous families containing ‘U-136.1’ chromosomes 6B, 5A, 6D, 1B, and 4B had a visually reduced spread of infection compared to lines having the ‘Hobbit-sib’ chromosome. Chromosome 2B from ‘U-136.1’ had an increased spread of infection. The critical chromosomes controlling seed weight were 6D, 3B, 5A, and 6B while those controlling deoxynivalenol (DON) content were homoeologous groups 2 and 6, although the latter effects were not significant due to a high coefficient of variation. Results from this and other studies show that chromosomes 6D, 6B, 5A, 4D, and 7A have frequently been associated with scab resistance in a number of wheat cultivars. Research groups now attempting to map scab resistance in wheat using markers should pay special attention to the above-mentioned chromosomes. [ABSTRACT FROM AUTHOR]

To determine whether resistance to Fusarium head blight in winter wheat is horizontal and non-species specific, 25 genotypes from five European countries were tested at six locations across Europe in the years 1990, 1991, and 1992. The five genotypes from each country had to cover the range from resistant to susceptible. The locations involved were Wageningen, Vienna, Rennes, Hohenheim, Oberer Lindenhof, and Szeged. In total, 17 local strains of Fusarium culmorum, F. graminearum, and F. nivale were used for experimental inoculation. One strain, F. culmorum IPO 39-01, was used at all locations. Best linear unbiased predictions (BLUPs) for the head blight ratings of the genotypes were formed within each particular location for each combination of year and strain. The BLUPs over all locations were collected in a genotype-by environment table in which the genotypic dimension consisted of the 25 genotypes, while the environmental dimension was made up of 59 year-by-strain-by-location combinations. A multiplicative model was fitted to the genotype by-environment interaction in this table. The inverses of the variances of the genotype-by-environment BLUPs were used as weights. Interactions between genotypes and environments were written as sums of products between genotypic scores and environmental scores. After correction for year-by-location influence very little variation in environmental scores could be ascribed to differences between strains. This provided the basis for the conclusion that the resistance to Fusarium head blight in winter wheat was of the horizontal and non-species specific type. There was no indication for any geographical pattern in virulence genes. Any reasonable aggressive strain, a F. culmorum strain for the cool climates and a F. graminearum strain for the warmer humid areas, should be satisfactory for screening purposes. [ABSTRACT FROM AUTHOR]

Demonstrates that the isotopic characteristics of basal ice containing debris from beneath the Greenland ice sheet can be understood only if isotope exchange between hydroxyl-bearing minerals and water are taken into account. Methods; Results; Discussion.