A total of 174 cereal-based food products, 67 compound feeds and 19 feed raw materials were analysed for the occurrence of deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, zearalenone, α-zearalenol, β-zearalenol, and their respective masked forms, including deoxynivalenol-3-glucoside, zearalenone-4-glucoside, α-zearalenol-4-glucoside, β-zearalenol-4-glucoside and zearalenone-4-sulfate. Fibre-enriched bread, bran-enriched bread, cornflakes, popcorn and oatmeal were collected in Belgian supermarkets from April 2010 to October 2011. All food samples analysed were contaminated with an average of 2 to 6 mycotoxins, including 1 to 3 masked forms. Feed raw materials that were used in the analysed compound feeds were collected by the manufacturer. Feed raw materials included were beet pulp, sunflower seed meal, soy bean, soy peel, oats, barley, maize germs, maize gluten feed, maize, wheat gluten feed, wheat bran pellets, wheat bran and wheat. Beet pulp, sunflower seed meal, soy bean and soy peel were hardly contaminated. The feed raw materials that were mostly infected with deoxynivalenol, zearalenone and derivatives were maize and its by-products. Also, the glucosylated and sulfated forms occurred in substantial amounts. As well, wheat and its by-products were contaminated with α-zearalenol (wheat gluten feed and wheat bran) and zearalenone (wheat). The contamination pattern and level of feed raw materials were reflected in the corresponding compound feeds.

Aspergillus flavus is the main producer of carcinogenic aflatoxins in agricultural commodities such as maize. This fungus occurs naturally on crops, and produces aflatoxins when environmental conditions are favorable. The aim of this study is to analyse the genetic variability among 109 A. flavus isolates previously recovered from maize sampled from a known aflatoxin-hotspot (Eastern region, Kenya) and the major maize-growing area in the Rift Valley (Kenya), and to determine their toxigenic potential. DNA analyses of internal transcribed spacer (ITS) regions of ribosomal DNA, partial β-tubulin gene (benA) and calmodulin gene (CaM) sequences were used. The strains were further analyzed for the presence of four aflatoxin-biosynthesis genes in relation to their capability to produce aflatoxins and other metabolites, targeting the regulatory gene aflR and the structural genes aflP, aflD, and aflQ. In addition, the metabolic profile of the fungal strains was unraveled using state-of-the-art LC-MS/MS instrumentation. The three gene-sequence data grouped the isolates into two major clades, A. minisclerotigenes and A. flavus. A. minisclerotigenes was most prevalent in Eastern Kenya, while A. flavus was common in both regions. A. parasiticus was represented by a single isolate collected from Rift Valley. Diversity existed within the A. flavus population, which formed several subclades. An inconsistency in identification of some isolates using the three markers was observed. The calmodulin gene sequences showed wider variation of polymorphisms. The aflatoxin production pattern was not consistent with the presence of aflatoxigenic genes, suggesting an inability of the primers to always detect the genes or presence of genetic mutations. Significant variation was observed in toxin profiles of the isolates. This is the first time that a profound metabolic profiling of A. flavus isolates was done in Kenya. Positive associations were evident for some metabolites, while for others no associations were found and for a few metabolite-pairs negative associations were seen. Additionally, the growth medium influenced the mycotoxin metabolite production. These results confirm the wide variation that exists among the group A. flavus and the need for more insight in clustering the group.

De novo shoot organogenesis (i.e., the regeneration of shoots on nonmeristematic tissue) is widely applied in plant biotechnology. However, the capacity to regenerate shoots varies highly among plant species and cultivars, and the factors underlying it are still poorly understood. Here, we evaluated the shoot regeneration capacity of 88 Arabidopsis thaliana accessions and found that the process is blocked at different stages in different accessions. We show that the variation in regeneration capacity between the Arabidopsis accessions Nok-3 and Ga-0 is determined by five quantitative trait loci (QTL): REG-1 to REG-5. Fine mapping by local association analysis identified RECEPTOR-LIKE PROTEIN KINASE1 (RPK1), an abscisic acid-related receptor, as the most likely gene underlying REG-1, which was confirmed by quantitative failure of an RPK1 mutation to complement the high and low REG-1 QTL alleles. The importance of RPK1 in regeneration was further corroborated by mutant and expression analysis. Altogether, our results show that association mapping combined with linkage mapping is a powerful method to discover important genes implicated in a biological process as complex as shoot regeneration.regeneration recalcitrance | SNP | ABA | natural variation | QTG

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Fusarium head blight (FHB) is a devastating disease of wheat, which is influenced by weather conditions and agronomic factors. Since FHB is a mostly monocyclic disease, the quantity of primary inoculum is a key factor influencing the FHB incidence. To investigate the connection between the primary Fusarium inoculum and the final population on wheat ears, naturally occurring populations of Fusarium avenaceum, Fusarium culmorum, Fusarium graminearum, Fusarium poae and Microdochium nivale were studied at eight locations in Flanders, Belgium. To determine the composition of the primary inoculum in November 2008, gramineous weeds, wheat residues, maize residues and soil samples were examined. In July 2009, wheat ears were examined to gain insight into the composition of the population at the end of the growing season. Comparing both populations can give an indication to what extent the primary inoculum in November 2008 contributes to the final FHB population in July 2009. Fusarium species residing saprophytically on gramineous weeds and crop residues or species persisting in soil as chlamydospores certainly contribute to the primary inoculum that will lead to infection of cereal crops grown on that field. Knowledge of the correlation between the primary inoculum and the composition of the FHB population at the end of the growing season can be important to predict the occurrence of FHB contamination and to implement control strategies for Fusarium Head Blight.