Nocardioides sp. strain WSN05-2, isolated from a wheat field, degrades deoxynivalenol, producing the novel intermediate 3-epi-deoxynivalenol

The mycotoxin deoxynivalenol (DON) causes serious problems worldwide in the production of crops such as wheat and barley because of its toxicity toward humans and livestock. A bacterial culture capable of degrading DON was obtained from soil samples collected in wheat fields using an enrichment culture procedure. The isolated bacterium, designated strain WSN05-2, completely removed 1,000???g/mL of DON from the culture medium after incubation for 10?days. On the basis of phylogenetic studies, WSN05-2 was classified as a bacterium belonging to the genus Nocardioides. WSN05-2 showed significant growth in culture medium with DON as the sole carbon source. High-performance liquid chromatography analysis indicated the presence of a major initial metabolite of DON in the culture supernatant. The metabolite was identified as 3-epi-deoxynivalenol (3-epi-DON) by mass spectrometry and ¹H and ¹³C nuclear magnetic resonance analysis. The amount of DON on wheat grain was reduced by about 90% at 7?days after inoculation with WSN05-2. This is the first report of a Nocardioides sp. strain able to degrade DON and of the yet unknown 3-epi-DON as an intermediate in the degradation of DON by a microorganism.     

Bacterial Cytochrome P450 System Catabolizing the Fusarium Toxin Deoxynivalenol

Deoxynivalenol (DON) is a natural toxin of fungi that cause Fusarium head blight disease of wheat and other small-grain cereals. DON accumulates in infected grains and promotes the spread of the infection on wheat, posing serious problems to grain production. The elucidation of DON-catabolic genes and enzymes in DON-degrading microbes will provide new approaches to decrease DON contamination. Here, we report a cytochrome P450 system capable of catabolizing DON in Sphingomonas sp. strain KSM1, a DON-utilizing bacterium newly isolated from lake water. The P450 gene ddnA was cloned through an activity-based screening of a KSM1 genomic library. The genes of its redox partner candidates (flavin adenine dinucleotide [FAD]-dependent ferredoxin reductase and mitochondrial-type [2Fe-2S] ferredoxin) were not found adjacent to ddnA; the redox partner candidates were further cloned separately based on conserved motifs. The DON-catabolic activity was reconstituted in vitro in an electron transfer chain comprising the three enzymes and NADH, with a catalytic efficiency (k_cat/K_m) of 6.4 mM⁻¹ s⁻¹. The reaction product was identified as 16-hydroxy-deoxynivalenol. A bioassay using wheat seedlings revealed that the hydroxylation dramatically reduced the toxicity of DON to wheat. The enzyme system showed similar catalytic efficiencies toward nivalenol and 3-acetyl deoxynivalenol, toxins that frequently cooccur with DON. These findings identify an enzyme system that catabolizes DON, leading to reduced phytotoxicity to wheat.     

Co-occurrence of five Fusarium toxins in corn-Dried Distiller’s Grains with Solubles in Thailand and comparison of ELISA and LC-MS/MS for fumonisin analysis

Dried Distiller’s Grains with Solubles (DDGS), a by-product of bio-ethanol production from maize and other cereals, is increasingly used as a feed additive. In this study, five Fusarium toxins, including fumonisin B₁ (FB₁), fumonisin B₂ (FB₂), deoxynivalenol (DON), zearalenone (ZEN) and beauvericin (BEA) were quantified by LC-MS/MS in 59 corn-DDGS samples. In addition, the fumonisin level in 30 randomly selected-samples was compared using an ELISA detection technique. No sample was free from mycotoxin contamination, and 50.8 % of the samples were co-contaminated with all five mycotoxins. Moreover, toxin levels were generally high, with mean levels of 9 mg kg^?1 FB₁, 6 mg kg^?1 FB₂, 1.2 mg kg^?1 DON, 0.9 mg kg^?1 ZEN, and 0.35 mg kg^?1 BEA. Maximum levels for FB₁ (143 mg kg^?1) and FB₂ (125 mg kg^?1) are of acute toxicological relevance. The ELISA method had a tendency to underestimate the fumonisin content when compared with LC-MS/MS. Finally, this is the first reported beauvericin contamination in corn-DDGS.     

Toxigenic Fusarium species infecting wheat heads in Poland

Toxigenic Fusarium species are common pathogens of wheat and other cereals worldwide. In total, 449 wheat heads from six localities in Poland, heavily infected with Fusarium during 2009 season, were examined for Fusarium species identification. F. culmorum was the most common species (72.1% on average) with F. graminearum and F. avenaceum the next most commonly observed, but much less frequent (13.4 and 12.5% respectively). F. cerealis was found in 1.8% of all samples, and F. tricinctum was found only in one sample (0.2%). Subsequent quantification of the three major mycotoxins (deoxynivalenol, zearalenone and moniliformin) in grain and chaff fractions with respect to associated prevailing pathogen species uncovered the following patterns. Moniliformin (MON) was found in low amounts in all samples with F. avenaceum present. In contrast, deoxynivalenol (DON) and zearalenone (ZEA) were the contaminants of F. culmorum- and F. graminearum-infected heads. The highest concentration of DON was recorded in grain sample collected in Radzików (77 µg g^?1). High temperatures in Central Poland during July and August accompanied with high rainfall in July were responsible for this high DON accumulation. Trichothecene, zearalenone, enniatin and beauvericin chemotypes were identified among 21 purified isolates using gene-specific PCR markers.     

Comparison of the efficacy of chitosan with that of a fluorescent pseudomonad for the control of Fusarium head blight disease of cereals and associated mycotoxin contamination of grain

Fusarium culmorum can cause Fusarium head blight (FHB) disease of cereals, resulting in yield loss and contamination of grain with the trichothecene mycotoxin, deoxynivalenol (DON). In this study, we compared the efficacy of a biological control agent (Pseudomonas fluorescens strain MKB 158) with the biochemical chitosan (the deacetylated derivative of chitin) in controlling FHB disease of wheat and barley. Both agents were equally effective in reducing DON contamination of grain caused by F. culmorum. Under both glasshouse and field conditions, treatment with commercially available crabshell-derived chitosan reduced the severity of FHB symptom development on wheat and barley by ?74% (P ? 0.050). While treatment with P. fluorescens reduced the severity of FHB symptom development on these cereals by ?48% (P ? 0.050). Chitosan and P. fluorescens respectively prevented ?58 and ?35% of the FHB-associated reductions in 1000-grain weight in wheat and barley (P ? 0.050). Both agents significantly reduced the DON content of wheat and barley under both glasshouse and field conditions (P ? 0.050) and were equally efficacious in doing so (?74 and ?79% reductions due to chitosan and P. fluorescens, respectively). Crude chitin extracts from crabshells and crude chitosan-based formulations prepared from crabshells and eggshells were also tested under field conditions, but were not as effective as the commercial crabshell-derived preparation in controlling FHB disease. This is the first report on the use of chitosan for the control of Fusarium head blight disease and DON contamination of grain.     

Suppression of wheat Fusarium head blight by novel amphiphilic aminoglycoside fungicide K20

K20 is a novel amphiphilic aminoglycoside capable of inhibiting many fungal species. K20's capabilities to inhibit Fusarium graminearum the causal agent wheat Fusarium head blight (FHB) and to this disease were examined. K20 inhibited the growth of F. graminearum (minimum inhibitory concentrations, 7.8–15.6 mg L^?1) and exhibited synergistic activity when combined with triazole and strobilurin fungicides. Application of K20 up to 720 mg L^?1 to wheat heads in the greenhouse showed no phytotoxic effects. Spraying wheat heads in the greenhouse with K20 alone at 360 mg L^?1 lowered FHB severity below controls while combining K20 with half–label rates of Headline (pyraclostrobin) improved its disease control efficacy. In field trials, spraying K20 at 180 mg L^?1 and 360 mg L^?1 combined with half-label rates of Headline, Proline 480 SC (prothioconazole), Prosaro 421 SC (prothioconazole + tebuconazole), and Caramba (metconazole) reduced FHB indices synergistically. In addition, the K20 plus Proline 480 SC combination reduced levels of the mycotoxin deoxinivalenol by 75 % compared to the control. These data suggest that K20 may be useful as a fungicide against plant diseases such as FHB particularly when combined with commercial fungicides applied at below recommended rates.     

Effects of deoxynivalenol and zearalenone on oxidative stress and blood phagocytic activity in broilers

Effects of dietary contamination with various levels of deoxynivalenol (DON) and zearalenone (ZEA) were investigated on Ross 308 hybrid broilers of both sexes. After hatching, all chickens were fed an identical control diet for two weeks. Then chickens of Group 1 received a diet contaminated with DON and ZEA, both being 3.4 mg · kg^?1, while Group 2 received DON and ZEA at 8.2 and 8.3 mg · kg^?1, respectively. The diet of the control group contained background levels of mycotoxins. Samples of blood and tissues were collected after two weeks. Intake of both contaminated diets resulted in a significantly decreased activity of glutathione peroxidase (GPx) and increased level of malondialdehyde (MDA) in liver tissue, while in kidneys the concentration of MDA was significantly increased only in Group 1. On the other hand, activities of blood GPx and plasma γ-glutamyltransferase (GGT) were elevated in Group 2 only. Activities of thioredoxin reductase in liver and GPx in duodenal mucosa tissues, superoxide dismutase (SOD) in erythrocytes as well as levels of MDA in duodenal mucosa and α-tocopherol in plasma were not affected by dietary mycotoxins. Blood phagocytic activity was significantly depressed in Group 1 and 2. These results demonstrate that diets contaminated with DON and ZEA at medium levels are already able to induce oxidative stress and compromise the blood phagocytic activity in fattening chickens.     

Molecular characterization of field resistance to Fusarium head blight in two US soft red winter wheat cultivars

In the soft red winter wheat (Triticum aestivum L.) regions of the US, Fusarium head blight (FHB, caused by Fusarium spp.) resistance derived from locally adapted germplasm has been used predominantly. Two soft red winter wheat cultivars, Massey and Ernie, have moderate resistance to FHB. Mapping populations derived from Becker/Massey (B/M) and Ernie/MO 94-317 (E/MO) were evaluated for FHB resistance and other traits in multiple environments. Eight QTL in B/M and five QTL in E/MO were associated with FHB variables including incidence, severity (SEV), index (IND), Fusarium damaged kernels (FDK), deoxynivalenol (DON), and morphological traits flowering time and plant height. Four QTL were common to both populations. Three of them were located at or near known genes: Ppd-D1 on chromosome 2DS, Rht-B1 on 4BS, and Rht-D1 on 4DS. Alleles for dwarf plant height (Rht-B1b and Rht-D1b) and photoperiod insensitivity (Ppd-D1a) had pleiotropic effects in reducing height and increasing FHB susceptibility. The other QTL detected for FHB variables were on 3BL in both populations, 1AS, 1DS, 2BL, and 4DL in B/M, and 5AL (B1) and 6AL in E/MO. The additive effects of FHB variables ranged from 0.4 mg kg^?1 of DON to 6.2 % for greenhouse (GH) SEV in B/M and ranged from 0.3 mg kg^?1 of DON to 8.3 % for GH SEV in E/MO. The 4DS QTL had epistasis with Ppd-D1, Qdon.umc-6AL, and Qht.umc-4BS, and additive × additive × environment interactions with the 4BS QTL for SEV, IND, and FDK in E/MO. Marker-assisted selection might be used to enhance FHB resistance through selection of favorable alleles of significant QTL, taking into account genotypes at Rht-B1b, Rht-D1a and Ppd-D1a.     

Yield stability of hybrids versus lines in wheat,barley, and triticale

Key message

We present experimental data for wheat, barley, and triticale suggesting that hybrids manifest on average higher yield stability than inbred lines.

Abstract

Yield stability is assumed to be higher for hybrids than for inbred lines, but experimental data proving this hypothesis is scarce for autogamous cereals. We used multi-location grain yield trials and compared the yield stability of hybrids versus lines for wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and triticale (×Triticosecale Wittmack). Our study comprised three phenotypic data sets of 1,749 wheat, 96 barley, and 130 triticale genotypes, which were evaluated for grain yield in up to five contrasting locations. Yield stability of the group of hybrids was compared with that of the group of inbred lines estimating the stability variance. For all three crops we observed a significantly (P < 0.05) higher yield stability of hybrids compared to lines. The enhanced yield stability of hybrids as compared to lines represents a major step forward, facilitating coping with the increasing abiotic stress expected from the predicted climate change.     

Concentration of ergosterol in small-grained naturally contaminated and inoculated cereals

Ergosterol (ERG) is a major sterol constituent of most fungi. Its concentration is negligible in higher plants, but can be used as a chemical marker of the presence of fungal contaminations. In this study, ERG concentration was assessed in randomly collected samples of naturally contaminated grain (wheat, barley and oat) and in samples of grain (wheat, barley, triticale and oat) harvested after inoculation of heads with conidia of different Fusarium species. Wheat samples were analysed at three stages of grain development. The lowest ERG concentration was found in non-inoculated samples at the first stage of grain development. This concentration was increasing with grain ripening. In naturally contaminated samples collected after harvest, ERG concentration was lower in wheat than in barley and oat. ERG concentrations in inoculated samples varied significantly, but were always significantly higher than in naturally contaminated samples. In the above cereal samples it was much lower than the levels assayed in laboratory cultures inoculated with fungi from genus Fusarium. The content of ERG was also analyzed in milling products of small-grained cereals and other foodstuffs, where a considerable variation was observed. The lowest ERG amounts were assayed in flours with a high degree of purification, while the highest ones in case of flours and products with a low purification rate. The results indicate the potential application of HPLC combined with microwave-assisted extraction both when assaying samples with low ERG concentrations (naturally contaminated) and those characterized with high contents of fungal biomass (strongly infected, artificially inoculated). It also facilitates analyses of fungal biomass in technological processes, where results may be expected to vary considerably.     

Zinc seed coating improves the growth,grain yield and grain biofortification of bread wheat

This study, comprising three independent experiments, was conducted to optimize the zinc (Zn) application through seed coating for improving the productivity and grain biofortification of wheat. Experiment 1 was conducted in petri plates, while experiment 2 was conducted in sand-filled pots to optimize the Zn seed coating using two sources (ZnSO₄, ZnCl₂) of Zn. In the first two experiments, seeds of two wheat cultivars Lasani-2008 and Faisalabad-2008 were coated with 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75 and 2.00 g Zn kg^?1 seed using ZnSO₄ and ZnCl₂ as Zn sources. The results of experiment I revealed that seed coating with 1.25 and 1.50 g Zn kg^?1 seed using both sources of Zn improved the seedling emergence. However, seed coated with 1.25 and 1.50 g Zn kg^?1 seed using ZnSO₄ was better regarding improvement in seedling growth and seedling dry weight. The results of the second experiment indicated that seed coated with 1.25 and 1.50 g Zn kg^?1 seed using ZnSO₄ improved the seedling emergence and seedling growth of tested wheat cultivars. However, seed coating beyond 1.5 g Zn kg^?1 seed using either Zn source suppressed the seedling emergence. Third experiment was carried out in glass house in soil-filled earthen pots. Seeds of both wheat cultivars were coated with pre-optimized treatments (1.25, 1.50 g Zn kg^?1 seed) using both Zn sources. Seed coating with all treatments of ZnSO₄ and seed coating with 1.25 g Zn kg^?1 seed using ZnCl₂ improved the seedling emergence and yield-related traits of wheat cultivars. Seed coating with 1.25 g Zn kg^?1 seed also improved the chlorophyll a and b contents. Maximum straw Zn contents, before and after anthesis, were recorded from seed coated with 1.5 g Zn kg^?1 seed using either Zn source. Increase in grain yield from seed coating followed the sequence 1.25 g Zn kg^?1 seed (ZnSO₄) >1.25 g Zn kg^?1 seed (ZnCl₂) >1.5 g Zn kg^?1 seed (ZnSO₄). However, increase in grain Zn contents from seed coated was 1.5 g Zn kg^?1 seed (ZnCl₂) >1.25 and 1.5 g Zn kg^?1 seed (ZnCl₂, ZnSO₄) >1.25 g Zn kg^?1 seed (ZnSO₄). Seed coating with Zn increased the grain Zn contents from 21 to 35 %, while 33–55 % improvement in grain yield was recorded. In conclusion, wheat seeds may be coated with 1.25 g Zn kg^?1 seed using either source of Zn for improving the grain yield and grain Zn biofortification.     

Analysis of promoters in transgenic barley and wheat

Advances in the genetic transformation of cereals have improved the prospects of using biotechnology for plant improvement, and a toolbox of promoters with defined specificities would be a valuable resource in controlling the expression of transgenes in desired tissues for both plant improvement and molecular farming. A number of promoters have been isolated from the important cereals (wheat, barley, rice and maize), and these promoters have been tested mostly in homologous cereal systems and, to a lesser extent, in heterologous cereal systems. The use of these promoters across the important cereals would add value to the utility of each promoter. In addition, promoters with less sequence homology, but with similar specificities, will be crucial in avoiding homology-based gene silencing when expressing more than one transgene in the same tissue. We have tested wheat and barley promoters in transgenic barley and wheat to determine whether their specificity is shared across these two species. The barley bifunctional α-amylase/subtilisin inhibitor ( Isa ) promoter, specific to the pericarp in barley, failed to show any activity in wheat, whereas the wheat early-maturing ( Em ) promoter showed similar activity in wheat and barley. The wheat high-molecular-weight glutenin ( HMW-Glu ) and barley D-hordein ( D-Hor ) and B-hordein ( B-Hor ) storage protein promoters maintained endosperm-specific expression of green fluorescent protein (GFP) in wheat and barley, respectively. Using gfp , we have demonstrated that the Isa and Em promoters can be used as strong promoters to direct transgenes in specific tissues of barley and wheat grain. Differential promoter activity across cereals expands and adds value to a promoter toolbox for utility in plant biotechnology.     

Grain zinc, iron and protein concentrations and zinc-efficiency in wild emmer wheat under contrasting irrigation regimes

Micronutrient malnutrition, and particularly deficiency in zinc (Zn) and iron (Fe), afflicts over three billion people worldwide, and nearly half of the world’s cereal-growing area is affected by soil Zn deficiency. Wild emmer wheat [Triticum turgidum ssp. dicoccoides (Körn.) Thell.], the progenitor of domesticated durum wheat and bread wheat, offers a valuable source of economically important genetic diversity including grain mineral concentrations. Twenty two wild emmer wheat accessions, representing a wide range of drought resistance capacity, as well as two durum wheat cultivars were examined under two contrasting irrigation regimes (well-watered control and water-limited), for grain yield, total biomass production and grain Zn, Fe and protein concentrations. The wild emmer accessions exhibited high genetic diversity for yield and grain Zn, Fe and protein concentrations under both irrigation regimes, with a considerable potential for improvement of the cultivated wheat. Grain Zn, Fe and protein concentrations were positively correlated with one another. Although irrigation regime significantly affected ranking of genotypes, a few wild emmer accessions were identified for their advantage over durum wheat, having consistently higher grain Zn (e.g., 125 mg kg^?1), Fe (85 mg kg^?1) and protein (250 g kg^?1) concentrations and high yield capacity. Plants grown from seeds originated from both irrigation regimes were also examined for Zn efficiency (Zn deficiency tolerance) on a Zn-deficient calcareous soil. Zinc efficiency, expressed as the ratio of shoot dry matter production under Zn deficiency to Zn fertilization, showed large genetic variation among the genotypes tested. The source of seeds from maternal plants grown under both irrigation regimes had very little effect on Zn efficiency. Several wild emmer accessions revealed combination of high Zn efficiency and drought stress resistance. The results indicate high genetic potential of wild emmer wheat to improve grain Zn, Fe and protein concentrations, Zn deficiency tolerance and drought resistance in cultivated wheat.     

Regulation of heavy metal concentrations in cereal grains from uranium mine soils

Aims

Along a gradient of diminishing heavy metal (HM) concentrations formed by local inclusions of uranium mine soils into non-contaminated cropland, duplicate 1-m² plots of 3 winter wheat cvs. (Akteur E, Brilliant A, and Bussard E) were established at 3 positions within a winter rye (cv. Visello) culture. It was the goal to determine permissible soil HM concentrations tolerated by cereal cvs. with variable excluder properties, and regulatory mechanisms which optimize the concentrations of essential minerals and radionuclide analogues in viable seeds from geologically related soils with diverging HM content.

Methods

Total metal concentrations / nitrogen species in soils, shoots, and mature grains were determined by ICP-MS / spectrophotometry, and Kjeldahl analyses.

Results

No non-permissible concentrations in grains of the 4 cereal cvs. were caused by elevated but aged total soil resources (mg kg^-1 DW) in As (156); Cu (283); Mn (2,130); Pb (150); and in Zn (3,005) in the case of Bussard although CdCuZn elicited phytotoxicity symptoms. Uranium (41) contaminated grains of Akteur and Brilliant but not of Bussard and Visello due to their excluder properties. The concentration in Cd (41) had to be reduced to 20/2 mg kg^-1 for the production by excluder cvs. of fodder/food grains. Cultivars excluding both HM and radionuclide analogues such as BaCsSr synchronously were not identified. Whereas plant tissue concentrations in the metalloprotein-associated elements CdCoCuMnNiZn rise and fall generally with N_org, grains of the wheat cvs. differed too little in N_org to designate variations in their metal acquisition rates solely as protein-regulated. Wheat grains confined nevertheless the concentrations in Cu to 11–14 mg kg^-1 although the respective soil concentrations varied by factor 19. Grain deposition in CaFeMn(Zn) and in nuclides followed the same rules.

Conclusions

It is hypothesized that cereals down-/up-regulate grain:soil transfer rates from soils with excessive/deficient trace metal resources to equip viable seeds with an optimum but not maximum in essential minerals. Positive correlations between metal concentrations in planta to those in soil can thereby be lost.     

Hyperaccumulation of thallium is population-specific and uncorrelated with caesium accumulation in the thallium hyperaccumulator, Biscutella laevigata

Purpose

This study investigated the residual contribution of legume and fertilizer nitrogen (N) to a subsequent crop under the effect of elevated carbon dioxide concentration ([CO₂]).

Methods

Field pea (Pisum sativum L.) was labeled in situ with ¹⁵N (by absorption of a ¹⁵N-labeled urea solution through cut tendrils) under ambient and elevated (700 μmol mol^–1) [CO₂] in controlled environment glasshouse chambers. Barley (Hordeum vulgare L.) and its soil were also labeled under the same conditions by addition of ¹⁵N-enriched urea to the soil. Wheat (Triticum aestivum L.) was subsequently grown to physiological maturity on the soil containing either ¹⁵N-labeled field pea residues (including ¹⁵N-labeled rhizodeposits) or ¹⁵N-labeled barley plus fertilizer ¹⁵N residues.

Results

Elevated [CO₂] increased the total biomass of field pea (21 %) and N-fertilized barley (23 %), but did not significantly affect the biomass of unfertilized barley. Elevated [CO₂] increased the C:N ratio of residues of field pea (18 %) and N-fertilized barley (19 %), but had no significant effect on that of unfertilized barley. Elevated [CO₂] increased total biomass (11 %) and grain yield (40 %) of subsequent wheat crop regardless of rotation type in the first phase. Irrespective of [CO₂], the grain yield and total N uptake by wheat following field pea were 24 % and 11 %, respectively, higher than those of the wheat following N-fertilized barley. The residual N contribution from field pea to wheat was 20 % under ambient [CO₂], but dropped to 11 % under elevated [CO₂], while that from fertilizer did not differ significantly between ambient [CO₂] (4 %) and elevated [CO₂] (5 %).

Conclusions

The relative value of legume derived N to subsequent cereals may be reduced under elevated [CO₂]. However, compared to N fertilizer application, legume incorporation will be more beneficial to grain yield and N supply to subsequent cereals under future (elevated [CO₂]) climates.     

Occurrence of different trichothecenes and deoxynivalenol-3-β-d-glucoside in naturally and artificially contaminated Danish cereal grains and whole maize plants

Fusarium mycotoxins such as deoxynivalenol (DON) can occur in cereals conjugated to glucose and probably also to other sugars. These conjugates, which are often referred to as ??masked mycotoxins??, will not be detected with routine analytical techniques. Furthermore, it is suspected that the parent toxin may again be released after hydrolysis in the digestive tracts of animals and humans. Today, our knowledge of the occurrence of these compounds in cereal grains is limited. In this paper, a LC-MS/MS method for the simultaneous determination of DON, deoxynivalenol-3-??-d-glucoside (DON-3-glucoside), 3 acetyl-DON, nivalenol, fusarenon-X, diacetoxyscirpenol, HT-2 toxin, and T-2 toxin in naturally (n?=?48) and artificially (n?=?30) contaminated cereal grains (wheat, barley, oat, rye triticale) is reported. The method has also been applied to whole fresh maize plant intended for production of maize silage (n?=?10). The samples were collected from the harvest years 2006?C2010, The results show that DON-3-glucoside and DON co-occurred in cereal grains and, especially in several of the highly contaminated samples, the concentration of the glucoside can be relatively high, corresponding to over 37?% of the DON concentration. The DON-3-glucoside levels in both the naturally and in the artificially grain inoculated with Fusarium were second only to DON, and were generally higher than those of the other tested trichothecenes, which were found at low concentrations in most samples, in many cases even below the detection limit of the method. This argues for the importance of taking DON-3-glucoside into account in the ongoing discussion within the European Community concerning exposure re-evaluations for setting changed values for the tolerable intake for DON. Our results indicate that, in the naturally contaminated grains and in the Fusarium infested cereal grains (winter and spring wheat, oat, triticale), the concentration level of DON-3-glucoside is positively correlated to the DON content. When the DON concentration is high, then the content of DON-3-glucoside will most probably also be high and vice versa.     

A novel <Emphasis Type="Italic">Trichoderma</Emphasis> fusant for enhancing nutritional value and defence activity in chickpea

In recent years, due to the rise in food consumption, much of the attention has been focused to increase the yield of the agricultural crops which resulted in compromised nutritional quality. Efforts have to be undertaken to enhance the nutritional attributes of legumes, cereals and staple food crops by increasing amino acids and mineral content. In the present study, we evaluated a protoplast fusant (H. lixii MTCC 5659) for its ability to enhance nutritional value and defence activity in chickpea. Essential amino acids; methionine (9.82 mg kg^?1 dw), cysteine (2.61 mg kg^?1 dw), glycine (11.34 mg kg^?1 dw), valine (9.26 mg kg^?1 dw), and non-essential amino acids; aspartic acid (39.19 mg kg^?1 dw) and serine (17.53 mg kg^?1 dw) were significantly higher in seeds of fusant inoculated chickpea. Fusant significantly improved accumulation of mineral nutrients i.e. Cu (157.73 mg kg^?1 dw), Co (0.06 mg kg^?1 dw), Ni (1.85 mg kg^?1 dw), Zn (157.73 mg kg^?1 dw) and S (16.29 mg kg^?1 dw) in seeds. Biocontrol and defence activities of chickpea increased from 20 to 35% in fusant inoculated plants suggesting its potential to ameliorate biotic stress. To the best of our knowledge, this is the first report of an increase in amino acids and mineral content of chickpea by fusant inoculation.     

Determination of B-trichothecenes in wheat by post column derivatisation liquid chromatography with fluorescence detection (PCD-HPLC-FLD)

B-trichothecenes are one of the most common contaminants of cereals in Europe. Therefore, the use of fast and accurate methods is necessary to measure contamination levels and observe regulatory limits. At the moment, mostly gas chromatographic (GC) methods are used but HPLC-UV methods are also employed. Clean-up is commonly done either with immunoaffinity or Mycosep® columns. In the Christian Doppler Laboratory for Mycotoxin Research we have established an alternative HPLC method with post column derivatisation (PCD) as an alternative to existing chromatographic methods. This PCD-HPLC-FLD method uses a Mycosep® clean-up and allows the simultaneous detection and quantification of deoxynivalenol, nivalenol, fusarenon X, 3-acetyldeoxynivalenol and 15-acetyldeoxynivalenol. A validation with wheat gave for deoxynivalenol a limit of quantification ten times below the drafted European Union guideline level (500 µg.kg^?1) and a limit of detection of 8 µg.kg^?1. The relative standard derivation for DON was 10% (n=30). The obtained mean recovery rate for DON was 90% in a range from 50 to 1000 µg.kg^?1.     

Effects of long-term storage on Fusarium toxin concentrations in wheat - sources of error of the analytical results

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.