Mycotoxins: occurrence, toxicology, and exposure assessment.

The Fusarium species predominantly found associated with Fusarium head blight (FHB) in wheat and other small-grain cereals all over Europe are F. graminearum, F. avenaceum and F. culmorum. Among the less frequently encountered species are several others which are less pathogenic or opportunistic, but also toxigenic. These include F. poae, F. cerealis, F. equiseti, F. sporotrichioides, F. tricinctum and, to a lesser extent, F. acuminatum, F. subglutinans, F. solani, F. oxysporum, F. verticillioides, F. semitectum and F. proliferatum. The species profile of FHB is due to several factors, primarily climatic conditions, particularly rain and the temperature at flowering stage, but also agronomic factors, such as soil cultivation, nitrogen fertilization, fungicides, crop rotation, and host genotype. The most frequently encountered Fusarium mycotoxins in FHB in Europe has proved to be deoxynivalenol and zearalenone produced by F. graminearum and F. culmorum, with the former more common in southern (warmer) and the latter in northern (colder) European areas. Nivalenol was usually found associated with deoxynivalenol and its derivatives (mono-acetyldeoxynivalenols), together with fusarenone-X, formed by F. graminearum, F. cerealis, F. culmorum and, in northern areas, by F. poae. Moreover, from central to northern European countries, moniliformin has been consistently reported, as a consequence of the widespread distribution of F. avenaceum, whereas the occurrence of T-2 toxin derivatives, such as T-2 toxin and HT-2 toxin, and diacetoxyscirpenol have been recorded in conjunction with sporadic epidemics of F. sporotrichioides and F. poae. Finally, beauvericin and various enniatins have recently been found in Finnish wheat colonized by F. avenaceum and F. poae.

Toxigenic Fusarium species and mycotoxins associated with head blight in small-grain cereals in Europe

Detection and analysis of genetic variation can help us to understand the molecular basis of various biological phenomena in plants. Since the entire plant kingdom cannot be covered under sequencing projects, molecular markers and their correlation to phenotypes provide us with requisite landmarks for elucidation of genetic variation. Genetic or DNA based marker techniques such as RFLP (restriction fragment length polymorphism), RAPD (random amplified polymorphic DNA), SSR (simple sequence repeats) and AFLP (amplified fragment length polymorphism) are routinely being used in ecological, evolutionary, taxonomical, phylogenic and genetic studies of plant sciences. These techniques are well established and their advantages as well as limitations have been realized. In recent years, a new class of advanced techniques has emerged, primarily derived from combination of earlier basic techniques. Advanced marker techniques tend to amalgamate advantageous features of several basic techniques. The newer methods also incorporate modifications in the methodology of basic techniques to increase the sensitivity and resolution to detect genetic discontinuity and distinctiveness. The advanced marker techniques also utilize newer class of DNA elements such as retrotransposons, mitochondrial and chloroplast based microsatellites, thereby revealing genetic variation through increased genome coverage. Techniques such as RAPD and AFLP are also being applied to cDNA-based templates to study patterns of gene expression and uncover the genetic basis of biological responses. The review details account of techniques used in identification of markers and their applicability in plant sciences.

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Advances in molecular marker techniques and their applications in plant sciences

Risk assessment of the mycotoxin zearalenone.

Stability of mycotoxins during food processing.

Beauvericin is a cyclohexadepsipeptide mycotoxin which has insecticidal properties and which can induce apoptosis in mammalian cells. Beauvericin is produced by some entomo- and phytopathogenic Fusarium species (Fusarium proliferatum, F. semitectum, and F. subglutinans) and occurs naturally on corn and corn-based foods and feeds infected by Fusarium spp. We tested 94 Fusarium isolates belonging to 25 taxa, 21 in 6 of the 12 sections of the Fusarium genus and 4 that have been described recently, for the ability to produce beauvericin. Beauvericin was produced by the following species (with the number of toxigenic strains compared with the number of tested strains given in parentheses): Fusarium acuminatum var. acuminatum (1 of 4), Fusarium acuminatum var. armeniacum (1 of 3), F. anthophilum (1 of 2), F. avenaceum (1 of 6), F. beomiforme (1 of 1), F. dlamini (2 of 2), F. equiseti (2 of 3), F. longipes (1 of 2), F. nygamai (2 of 2), F. oxysporum (4 of 7), F. poae (4 of 4), F. sambucinum (12 of 14), and F. subglutinans (3 of 3). These results indicate that beauvericin is produced by many species in the genus Fusarium and that it may be a contaminant of cereals other than maize.

Beauvericin production by Fusarium species

List of Contributors. Preface. PART 1. BIOLOGY, ECOLOGY, TAXONOMY, PLANT DISEASES AND CONTROL 1. Alternaria taxonomy: Current Status, Viewpoint, Challenge (E. G. Simmons). 2. Occurrence of Alternaria Species in Countries of the Far East and their Taxonomy (S.-H. Yu). 3. Ecology and Nomenclature of Alternaria (H. Kwasna). 4. Ecological and Evolutionary Roles of Toxins from Alternaria Species Pathogenic to Plants (R. P. Scheffer). 5. Host-Specific Toxins of Alternaria Species (H. Otani, K. Kohmoto). 6. In Vitro Selection for Tobacco Cultivar Resistant to Alternaria alternata (Y. Ishida). 7. Alternaria Species that Attack Vegetable Crops: Biology and Options for Disease Management (J. O. Strandberg). 8. Alternaria Plant Diseases in Mediterranean Countries and Associated Mycotoxins (A. Bottalico, A. Logrieco). 9. Alternaria -Blight of Cotton: Epidemiology and Transmission (Y. Bashan, N. Y. Hernandes-Saavedra). 10. Epidemiology and Control of Dark Leaf Spot of Brassicas (F. M. Humpherson-Jones). 11. Alternaria Diseases of Linseed (B. D. L. Fitt, I. Vloutoglou). 12. Occurrence of Alternaria Species in Poland (H. Kwasna). 13. Carrot Seed-Borne Diseases Caused by Alternaria Species (K. Tylkowska). 14. Early Blight of Potato in some Regions of Eastern Europe (J. Kuczynska). 15. Metabolites Produced by Alternaria Species and their Natural Occurrence in Poland (J. Grabarkiewicz-Szczesna, J. Chelkowski). 16. Effects of Environment on Growth and Mycotoxin Production by Alternaria (J. Lacey). PART II. METABOLITES: PROPERTIES, BIOSYNTHESIS AND TOXICOLOGY 17. Toxicology of Alternaria Mycotoxins (M. A. Woody, F. S. Chu). 18. Regulation of Mycotoxin Biosynthesis in Alternaria (P. Haggblom, M. Hiltunen). 19. Alternaria Metabolites - Chemical and Biological Data (N. Montemurro, A. Visconti). Subject Index. Index of Fungi.

Alternaria: biology, plant diseases and metabolites.

In the present study, we reinvestigate the diversity of Trichoderma in Poland utilizing a combination of morphological and molecular/phylogenetic methods. A total of 170 isolates were collected from six different substrata at 49 sites in Poland. These were divided among 14 taxa as follows: 110 of 170 Trichoderma isolates were identified to the species level by the analysis of their ITS1, ITS2 rDNA sequences as: T. harzianum (43 isolates), T. aggressivum (35), T. citrinoviride (11), T. hamatum (9), T. virens (6), T. longibrachiatum (4), T. polysporum (1), and T. tomentosum (1); 60 isolates belonging to the Viride clade were identified based on a fragment of the translation-elongation factor 1-alpha (tef1) gene as: T. atroviride (20 isolates), T. gamsii (2), T. koningii (17), T. viridescens (13), T. viride (7), and T. koningiopsis (1). Identifications were made using the BLAST interface in TrichOKEY and TrichoBLAST (http://www.isth.info). The most diverse substrata were soil (nine species per 22 isolates) and decaying wood (nine species per 75 isolates). The most abundant species (25%) isolated from all substrata was T. harzianum.

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Species diversity of Trichoderma in Poland

Zearalenone is a mycotoxin produced by some Fusarium species in food and feed. From a global perspective, Fusarium mycotoxins may be considered as metabolites of particular importance to animal health and productivity. The aim of this review is to collect and summarise information concerning the properties of zearalenone, its derivatives and their biotransformation. Data on the occurrence and toxicity of zearalenone and a comparison of analytical methods used in zearalenone identification and quantification will also be discussed. As our awareness and understanding of the risks associated with zearalenone exposure increase, some countries set official or recommended limits in certain commodities.

Zearalenone and its metabolites: occurrence, detection, toxicity and guidelines

Fusarium head blight is a wheat disease of global importance and devastating impact in some years, especially in regions with high cereal production. Wheat grain contamination with mycotoxins is th...

Jerzy Chełkowski

Papers

Beauvericin production by Fusarium species

Alternaria: biology, plant diseases and metabolites.

Species diversity of Trichoderma in Poland

Zearalenone and its metabolites: occurrence, detection, toxicity and guidelines

Fusarium head blight of wheat: pathogenic species and their mycotoxins