BACKGROUND

The current status of research and research training in the subject area in the Nordic countries

  • The presence of mycotoxins in cereals is a serious and common quality problem that has become more obvious by recent years research. Fusarium spp. are known to produce a range of mycotoxins that cause human diseases such as cancer, hormonal disturbances and allergy. Some mycotoxins can, already in low quantities, influence the immune response system and inhibit both the protein and the DNA synthesis. The toxic compounds produced by the fungi include trichothecenes, fumonisines, fusarin C, beauvericin, enniatins, moniliformin and zearalenons among others. Several Fusarium species are pathogenic on cereals. The quantity and the population of Fusarium present on the grains, as well as environmental factors like temperature and humidity, can influence the amount of mycotoxins produced.
  • Dr. Tapani Yli-Mattila's research group has had collaboration with the research groups of Prof. Levitin and Dr. Mona Torp after the Fifth European Fusarium meeting in Szeged in 1997. After the year 1998 four researchers from All-Russian Plant Protection institute have visited the laboratory of Tapani Yli-Mattila at the University of Turku as a part of a bilaterial researcher exchange program between Finnish and Russian academies. Tapani Yli-Mattila, Aldo Rizzo, Ulf Thrane, Mona Torp and Sonja Klemsdal started the European collaboration in the COST 835 action "Agriculturally Important Toxigenic Fungi" in 1998-2003. Most of us were also involved in the NorFA course "Genes and Mycotoxins in Plant-Fungal interactions", which was organized by Prof. Henriette Giese in Copenhagen in August 2002. This gave us an idea to apply for a three-year grant for the network project "New emerging mycotoxins and toxigenic fungi in Northern Europe" from the Nordic Research Board (NordForsk). The network grant was accepted for one year and it included ca. 40 short visits (less than 10 days), two longer visits (3-4 weeks) three meetings and one laboratory course from July 2003 to June 2004. Unfortunately, it was the last year for this kind of academic activity in the NordForsk and was not possible to apply for additional years. Through this one year of networking though, all the involved institutions got the opportunity to become acquainted with the other institutions' laboratory facilities and ongoing research.
  • Dr. Tapani Yli-Mattila's research group has had collaboration with the research groups of Prof. Levitin and Dr. Mona Torp after the Fifth European Fusarium meeting in Szeged in 1997. After the year 1998 four researchers from All-Russian Plant Protection institute have visited the laboratory of Tapani Yli-Mattila at the University of Turku as a part of a bilaterial researcher exchange program between Finnish and Russian academies. Tapani Yli-Mattila, Aldo Rizzo, Ulf Thrane, Mona Torp and Sonja Klemsdal
  • During the first year of the network project the research groups at the University of Turku, the Norwegian Crop Research Inst., Plant Protection Centre and The Norwegian National Veterinary Institute have developed PCR-based molecular methods for identification and quantification of different plant-pathogenic and antagonistic fungal species and strains, and have also used DNA sequences for phylogenetic species identification. In a polyphasic study organised by Dr. Mona Torp through COST 835, the morphological and sequence data was combined with the metabolite data of the research group of Dr. U. Thrane at the Technical University of Denmark, and with other molecular and toxin data from other research groups of COST 835 to verify the presence of a new toxin producing species; Fusarium langsethiae in a study of ca. 100 Fusarium strains from different parts of the world. In this work the Russian culture collection of the laboratory of Prof. M. Levitin was very useful. The new member of our network project, Hans Pettersson is a coordinator of an EU-project on trichothecene analysis and a project leader in projects on trichothecene metabolism and toxicology.
  • Fusarium graminearum is the most quickly emerging toxigenic Fusarium species in Northern Europe. It has been much more common in Norway and Finland, but it has not yet been found in Northwestern Russia. The main toxins produced by F. graminearum are deoxynivalenol (DON) and zearalenone (ZEN). In Dr. Klemdals's research group work is in progress to clone and characterize genes involved in the synthesis of zearalenone. Once verified, this information can be used to screen isolates from the network for their ability to produce this mycotoxin.
  • In Northern Europe Fusarium avenaceum is the most common Fusarium species. This fungus, which has been considered nontoxigenic, was recently found to be able to produce the mycotoxins; moniliformin, enniatins and beauvericin. Dr. Rizzo was involved in the study, in which the Fusarium toxin, beauvericin, was as the first time found in cereal (rye) grains (Logrieco et al. 2002) and his research group as well as the Norwegian National Veterinary Insitute have also developed methods for quantification of moniliformin and enniatins in cereal grains. The research group of Ulf Thrane has studied metabolite profiles of F. avenaceum and F. tricinctum. Dr. Klemsdal's research group has already developed a quantitative PCR method for detecting F. avenaceum and trichothecene producing Fusarium strains in cereal grains, while Dr. Yli-Mattila's research group has developed quantitative PCR methods for F. graminearum and F. poae. Phylogenetic studies of F. avenaceum/F.arthrosporioides/F. tricinctum species complex are also going on at the research groups of Drs. Klemsdal, Yli-Mattila and Torp. Methods to study genetic variation between fungal isolates within species are also available in the network, e.g. AFLP (Klemsdal) UP-PCR and RAPD-PCR (Yli-Mattila) and DNA sequencing, microarray and data analyses (several laboratories in the network).

Prospects and need for Nordic co-operation in the subject area with particular reference to research training

  • The amount of mycotoxins present in cereals will differ between year and districts, and will also depend on resistance / susceptibility of the plant species or cultivar used.
  • The presence of living toxin producing fungi in cereals used for human food and animal feed can be avoided by correct methods of processing of the raw material. However, as many of the mycotoxins are heat stable, these compounds cannot be removed through the chain of processing, and once present in the grains at harvest, they will also be present in the final product.

  • To address this specific problem it is important that the research activities in the Nordic countries are co-ordinated. The current NordForsk network will facilitate such co-ordination.

  • In order to minimize occurrence and effects of new emerging mycotoxins and other secondary fungal metabolites in the food chain, it is necessary to determine the Fusarium and other toxigenic fungal species (e.g. Alternaria) composition on cereals and to characterize the populations and genetic structure of dominant Fusarium fungi and their toxins in Nordic countries and northwestern part of Russia (Leningrad region). There is also a need for a bioassay-guided search for new toxic fungal metabolites produced by the dominating fungal species on grain in this region. In addition, we will study the influence of geographical isolation and environmental factors on the formation of dominant species complex and population structure and to determine levels of different mycotoxins in cereals in Norway, Denmark, Finland and North-West Russia. New molecular techniques for early detection of toxigenic fungi will be used in order to understand the molecular basis of the toxigenicity. In addition, toxigenic Alternaria species will be studied in cereal grains.
  • The project is multidisciplinary (mycology, plant pathology, biochemistry, toxicology, molecular genetics) and has a strong system oriented component. This is a reason enough to set up a network because cooperation between different laboratories is essential for synergy and research efficiency.

  • The main goal of the network is to coordinate the Nordic research on Fusarium species of special interest to the Nordic countries in order to achieve synergy and research efficiency.

  • Sub-projects will be :
    1. Further analyses of taxa and metabolites of particular importance in the Nordic countries due to their occurrence, genetic variation, toxigenicity or pathogenicity. Also the biological relevance of biotic and abiotic interactions between Fusarium spp., their metabolites and their environment, will be studied.
    2. Development of diagnostic tools with particular emphasis on Nordic needs and potentially with the objective to commercialise the tools.
    3. Study the interaction between cereal plants and toxin producing fungi.
    4. Training of Nordic researchers and research students in relevant disciplines
  • The final goal of the second subproject is to develop quick and cheap molecular methods for the detection of toxigenic Fusarium strains from cereal grain samples used for food. The present chemical and microbiological methods are too expensive and/or slow for routine toxin analyses in grains.

  • In our study we will emphasise the study on the Fusarium avenaceum/F.arthrosporioides/F. tricinctum species complex and its toxins, since the taxonomy, toxins and other metabolites of this species complex are unclear and the majority of Fusarium isolates in grains in Northern Europe belong to this group. This species complex has been considered nontoxigenic, but recently it has been documented that several new toxins are produced by it in grains and other food products. Thus, one of the main goals of our project will be to clarify the occurrence, the taxonomy, mycotoxins and other toxic metabolites and quantification of Fusarium avenaceum/F. arthrosporioides/F .tricinctum species complex in Northern Europe. For this purpose isolates will be collected from all countries of the network project and the same well-characterized isolates will be delivered to all partners to be studied by different molecular, morphological, taxonomical and chemical analyses.
    The network project will continue the work of the network project "New emerging mycotoxins and toxigenic fungi in Northern Europe", which was funded for one year by the Nordic Council in 2003-2004.

  • In the present network, we want to utilize the knowledge of individual laboratories and to coordinate the work to avoid overlapping and achieving synergistic scientific effects instead. During visits of maximum 8 weeks the visitors will give a lecture about their work, and have opportunities to learn new methods and techniques and in most cases they will be able to start small projects, which will result in new publications. This is especially important for young researchers and doctoral students. We are also going write an additional application to NordForsk to organize a NordForsk course during the third year of the project. We will also arrange workshops during the network period.