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  • Author or Editor: A. Mesterházy x
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Fungal nonribosomal peptide synthetases (NRPSs) are responsible for the biosynthesis of numerous metabolites which serve as virulence factors in several plant-pathogen interactions. The aim of our work was to investigate the diversity of these genes in a Fusarium graminearum sequence database using bioinformatic techniques. Our search identified 15 NRPS sequences, among which two were found to be closely related to peptide synthetases of various fungi taking part in ferrichrome biosynthesis. Another peptide synthetase gene was similar to that identified in Aspergillus oryzae which is possibly responsible for the biosynthesis of fusarinine, an extracellular iron-chelating siderophore. To our knowledge, this is the first report on the identification of a putative NRPS gene possibly responsible for the biosynthesis of fusarinine-type siderophores. The other NRPSs were found to be related to peptide synthetases taking part in the biosynthesis of various peptides in other fungi. Transcription factors carrying ankyrin repeats were observed in the vicinity of four of the identified peptide synthetase genes. Additionally, NRPS related genes similar to putative long-chain fatty acid CoA ligases, acyl CoA ligases, ABC transport proteins, a highly conserved putative transmembrane protein of Aspergillus nidulans, and a-aminoadipate reductases have also been identified. Further studies are in progress to clarify the role of some of the identified NRPS genes in plant pathogenesis.

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We examined the blastogenic response to phytohaemaglutinin (PHA) in HLA-B8, DR3 positive and negative subjects in the presence or absence of the immunosuppressive Fusarium mycotoxin.  HLA-B8, DR3 haplotype was associated with a depression of the response to mitogen in the absence of the mycotoxin, whereas in the presence of deoxynivalenol we could not detect significant differences among individuals either possessing or lacking this haplotype.

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Type I resistance is a significant and powerful resistance component. Spraying inoculation covers reactions to both Type I and Type II. A significant synergetic effect was detected between Type I and Type II QTLs. It seems that Type I resistance at present cannot be directly measured, only as a difference between point and spraying inoculation. However, this does not influence the success of the selection. For breeding the spraying methodology is more suitable as it considers much wider genetic background than the point inoculation does. The highest resistance in the Szeged program was achieved by the use of exotic spring wheat sources in winter wheat, but excellent agronomy types were identified at a relative low ratio. Good or excellent resistance can be identified at a low rate in breeding material without exotic FHB resistance sources, but their agronomy value is much better. Ratio of high resistance is frequent in winter wheat lines created form winter and spring wheat resistance sources. An efficient phenotypic selection is inevitable. Repeatability of the test is generally good or excellent; LSD values are normally less than 10 % of the variation width. FDK and toxin measurements are integrant part of the program since 35 and 20 years, respectively. Several methodical considerations are discussed.

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Acta Archaeologica Academiae Scientiarum Hungaricae
Authors: K. Mesterházy, V. Kiss, D. Gabler, A. Márton, and L. Schilling
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Cereal Research Communications
Authors: Á. Mesterházy, B. Tóth, Á. Szabó-Hevér, J. Varga, and S. Lehoczki-Krsjak

An undescribed symptom caused by Fusarium graminearum was detected in wheat fields showing masses of orange sporodochia on the node and neighbouring stem tissue. Normally the head above infected nodes dies and only chaff is harvested. This is the first formal description of this type of stem infections caused by F. graminearum . The economic importance of these disease symptoms need further evaluation.

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Acta Agronomica Hungarica
Authors: B. Tóth, O. Török, É. Kótai, M. Varga, É. Toldiné Tóth, X. Pálfi, E. Háfra, J. Varga, J. Téren, and Á. Mesterházy

Aspergillus and Penicillium species and their mycotoxins, including aflatoxins, ochratoxins, fumonisins and patulin, are frequently encountered on cereal products. The occurrence of these species and their mycotoxins on maize was investigated in Hungary after harvest in two consecutive years. Surface-sterilized cereal seeds were placed on selective media, and the isolated fungal strains were identified using morphological methods. In 2010 and 2011, 81.94% and 14.33%, respectively, of the samples were found to be contaminated with potentially toxigenic isolates. The species identification of selected isolates was carried out using sequence-based methods. Several Aspergillus flavus isolates were identified, which are potential aflatoxin producers. Other mycotoxinproducing species were also isolated, including black Aspergilli, which potentially produce ochratoxins and fumonisins, and A. clavatus, which produces patulin. In 2010 a large number of Penicillium species occurred in the samples, producing a wide range of mycotoxins. The mycotoxin content of the samples was analysed using the ELISA and HPLC techniques. Aflatoxins were not detected in any of the samples, while ochratoxins and fumonisins were successfully identified in some of the maize seeds.

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Acta Botanica Hungarica
Authors: Cs. Molnár, Zs. Molnár, Z. Barina, N. Bauer, M. Biró, L. Bodonczi, A. Csathó, J. Csiky, J. Deák, G. Fekete, K. Harmos, A. Horváth, I. Isépy, M. Juhász, J. Kállayné Szerényi, G. Király, G. Magos, A. Máté, A. Mesterházy, A. Molnár, J. Nagy, M. Óvári, D. Purger, D. Schmidt, G. Sramkó, V. Szénási, F. Szmorad, Gy. Szollát, T. Tóth, T. Vidra, and V. Virók

The first version of the map of the Hungarian vegetation-based landscape regions were prepared at the scale of 1: 200,000 (1 km or higher resolution). The primary goal of the map was to provide an exact background for the presentation and evaluation of the data of the MÉTA database. Secondly, we intended to give an up-to-date and detailed vegetation-based division of Hungary with a comprehensive nomenclature of the regions. Regions were primarily defined on the basis of their present zonal vegetation, or their dominant extrazonal or edaphic vegetation. Where this was not possible, abiotic factors that influence the potential vegetation, the flora were taken into consideration, thus, political and economical factors were ignored. All region borders were defined by local expert botanists, mainly based on their field knowledge. The map differs in many features from the currently used, country-wide, flora-or geography-based divisions in many features. We consider our map to be temporary (i.e. a work map), and we plan to refine and improve it after 5 years of testing.

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