Sammendrag

The proportion of Norwegian wheat used for food has varied significantly during the recent decade, mainly because of the instability of factors that are essential to baking quality (i.e. protein content and gluten functionality). During the same period, serious contamination of Fusarium spp. and mycotoxins was observed in some grain lots [1, 2]. A project was established to generate greater knowledge of the interface between gluten functionality and effects of Fusarium species and other microorganisms on Norwegian wheat quality. Instances of severe degradation of gluten proteins that resulted in an almost complete loss of gluten functionality were observed in some lots of Norwegian wheat. The degradation of the gluten appeared to be caused by exogenous proteases. Metabarcoding of fungi and bacteria in these grain lots identified fungi within the Fusarium Head Blight complex, as well as one bacterial species, as candidate species for influencing gluten functionality. Some of these candidates were inoculated on wheat during flowering [3]. Analysis of baking quality of the flour from this experiment revealed a reduced proportion of un-extractable polymeric proteins (%UPP) and severe reductions in the gluten’s resistance to stretching (RMAX) in wheat flour from plants inoculated with Fusarium graminearum. Flour from wheat inoculated with Fusarium avenaceum was generally less infested, and showed minimal or no reduction in gluten functionality and %UPP compared to flour from the F. graminearum infested samples. Flour from wheat inoculated with Michrodochium majus is yet to be analysed. References 1. Koga, S., et al., Investigating environmental factors that cause extreme gluten quality deficiency in winter wheat (Triticum aestivum L.). Acta Agriculturae Scandinavica, Section B—Soil & Plant Science, 2016. 66(3): p. 237-246. 2. Hofgaard, I., et al., Associations between Fusarium species and mycotoxins in oats and spring wheat from farmers’ fields in Norway over a six-year period. World Mycotoxin Journal, 2016. 9(3): p. 365-378. 3. Nielsen, K.A.G., Effect of microorganisms on gluten quality in wheat., in Faculty of Biosciences. 2017, Norwegian University of Life Sciences: Ås.

Sammendrag

High concentrations of the mycotoxins HT-2 and T-2 (HT2 + T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing accumulation of HT2 + T2 in Norwegian oat grains. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). Spearman rank correlation coefficients were calculated between the HT2 + T2 contamination in oats at harvest and a range of weather summarisations within estimated phenological windows of growth stages in oats (tillering, flowering etc.). Furthermore, we developed a mathematical model to predict the risk of HT2 + T2 in oat grains. Our data show that adequate predictions of the risk of HT2 + T2 in oat grains at harvest can be achieved, based upon weather data observed during the growing season. Humid and cool conditions, in addition to moderate temperatures during booting, were associated with increased HT2 + T2 accumulation in harvested oat grains, whereas warm and humid weather during stem elongation and inflorescence emergence, or cool weather and absence of rain during booting reduced the risk of HT2 + T2 accumulation. Warm and humid weather immediately after flowering increased the risk, while moderate to warm temperatures and absence of rain during dough development, reduced the risk of HT2 + T2 accumulation in oat grains. Our data indicated that HT2 + T2 contamination in oats is influenced by weather conditions both pre- and post-flowering. These findings are in contrast with a previous study examining the risk of deoxynivalenol contamination in oat reporting that toxin accumulation was mostly influenced by weather conditions from flowering onwards.

Sammendrag

Fusarium head blight and seedling blight, both caused by Fusarium spp. and Microdochium spp., and glume blotch caused by Parastagonospora nodorum, are important diseases in wheat. In Norway, wheat seed lots are routinely analysed for infestation by these pathogens using traditional methods (plating grain on PDA, recording presence or absence of fungal colonies). This method is time consuming, require knowledge within fungal morphology, and do not facilitate identification to species in all cases. Molecular methods such as quantitative PCR (qPCR) could allow detection and quantification of fungal DNA at the species level in a relatively time effective way, particularly since the method allows for automation in different steps such as DNA extraction and pipetting. Whether the latter method is suitable within seed health evaluations will depend on the relationship between the amount of DNA of the different fungal species and field performance, and the purpose of the test (evaluation of planting value, need for seed treatment, survey of fungal species, quality of grain for consumption etc). To compare the two different methods, about 150 spring wheat seed lots from the years 2016-2017 (including two cultivars) were selected for the analysis of different fungi using species-specific qPCR and compared with the results from routine testing on PDA. In the 2016 material (81 samples), a mean seed infestation rate of 26% was observed for Microdochium spp. in the PDA test. The level of Fusarium was lower (mean infestation rate of 5%). A strong relationship was observed between the percentage of seeds infested by Microdochium and the level of Microdochium DNA (sum of DNA from Microdochium majus and Microdochium nivale) quantified by qPCR (R2 of 0.76, p<0.01). The relationship between Fusarium infested seeds and the level of Fusarium DNA (sum of DNA from three species) was moderate (R2 of 0.33, p<0.01). The samples were also analysed for the presence of P. nodorum. Compared to Fusarium and Microdochium, P. nodorum was present at an intermediate level (mean infestation rate of 12%). The relationship between the two different methods was weaker for this fungus (R2 of 0.21, p<0.01) than for Fusarium and Microdochium. The relationship between germination capacity and rating of the three groups of fungi by either method was studied. Preliminary results suggest that of the three fungi, Microdochium was associated with germination capacity in the 2016 material, and that the Microdochium infestation rate on PDA was slightly better correlated to germination capacity than the level of Microdochium DNA. Further results will be presented at the conference, including the association between the relative DNA content of the different Microdochium and Fusarium species and seed germination.

Sammendrag

The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in crop residues, weeds, and soil sampled from a selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. The different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence of F. langsethiae in oat. Results show that F. langsethiae DNA may occur in the oat plant already before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. No Fusarium DNA was detected in soil samples. Of the arthropods that were associated with the collected oat plants, aphids and thrips species were dominating. Further details will be given at the meeting.

Sammendrag

Over the recent decades, the Norwegian cereal industry has had major practical and financial challenges associated with the occurrence of Fusarium and mycotoxins in cereal grains. From 2011, payment reductions to farmers were implemented for oat grain lots with high levels of deoxynivalenol (DON). However, according to preliminary results by NIBIO, NMBU and Graminor, certain oat varieties with generally medium or low DON contamination, may contain high levels of HT-2 and T-2-toxins (HT2+T2). These mycotoxins, formed by Fusarium langsethiae, are considerably more toxic than DON. Resistance to F. langsethiae is not included in the variety screening in Norway. In 2016 a new project, SafeOats, was initiated. This project is led by NIBIO and is a collaboration between NIBIO, NMBU, Kimen, and the main Norwegian and Swedish breeding companies, Graminor and Lantmännen. Harper Adam University (UK) and Julius Kühn-Institut (Germany) are international collaborators. SafeOats will develop resistance screening methods in order to facilitate the phase-out of susceptible oat germplasm. Furthermore, SafeOats will give new insight into the biology of F. langsethiae and HT2+T2 accumulation in oats, and thus facilitate the choice of relevant control measures. The results from SafeOats will benefit consumers nationally and internationally by providing tools to increase the share of high quality grain into the food and feed industry. SafeOats is financed by The Foundation for Research Levy on Agricultural Products/Agricultural Agreement Research Fund/Research Council of Norway with support from the industry partners Graminor, Lantmännen, Kimen, Felleskjøpet Agri, Felleskjøpet Rogaland Agder, Fiskå Mølle Moss, Norgesmøllene and Strand Unikorn/Norgesfor.

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Sammendrag

During the last ten years, Norwegian cereal grain industry has experienced large challenges due to Fusarium spp. and Fusarium mycotoxin contamination of small-grained cereals. To prevent severely contaminated grain lots from entering the grain supply chain, it is important to establish surveys for the most prevalent Fusarium spp. and mycotoxins. The objective of our study was to quantify and calculate the associations between Fusarium spp. and mycotoxins prevalent in oats and spring wheat. In a 6-year period from 2004-2009, 178 grain samples of spring wheat and 289 samples of oats were collected from farmers’ fields in South East Norway. The grains were analysed for 18 different Fusarium-mycotoxins by liquid chromatography – mass spectrometry. Generally, the median mycotoxin levels were higher than reported in Norwegian studies covering previous years. The DNA content of Fusarium graminearum, Fusarium culmorum, Fusarium langsethiae, Fusarium poae and Fusarium avenaceum were determined by quantitative PCR. We identified F. graminearum as the main deoxynivalenol (DON) producer in oats and spring wheat, and F. langsethiae as the main HT-2 and T-2-toxins producer in oats. No association was observed between quantity of F. graminearum DNA and quantity of F. langsethiae DNA nor for their respective mycotoxins, in oats. F. avenaceum was one of the most prevalent Fusarium species in both oats and spring wheat. The following ranking of Fusarium species was made based on the DNA concentrations of the Fusarium spp. analysed in this survey (from high to low): F. graminearum = F. langsethiae = F. avenaceum > F. poae > F. culmorum (oats); F. graminearum = F. avenaceum > F. culmorum > F. poae = F. langsethiae (spring wheat). Our results are in agreement with recently published data indicating a shift in the relative prevalence of Fusarium species towards more F. graminearum versus F. culmorum in Norwegian oats and spring wheat.

Sammendrag

High concentrations of the mycotoxin deoxynivalenol (DON), produced by Fusarium graminearum have occurred frequently in Norwegian oats recently. Early prediction of DON levels is important for farmers, authorities and the Cereal Industry. In this study, the main weather factors influencing mycotoxin accumulation were identified and two models to predict the risk of DON in oat grains in Norway were developed: (1) as a warning system for farmers to decide if and when to treat with fungicide, and (2) for authorities and industry to use at harvest to identify potential food safety problems. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). A mathematical model was developed and used to estimate phenology windows of growth stages in oats (tillering, flowering etc.). Weather summarisations were then calculated within these windows, and the Spearman rank correlation factor calculated between DON-contamination in oats at harvest and the weather summarisations for each phenological window. DON contamination was most clearly associated with the weather conditions around flowering and close to harvest. Warm, rainy and humid weather during and around flowering increased the risk of DON accumulation in oats, as did dry periods during germination/seedling growth and tillering. Prior to harvest, warm and humid weather conditions followed by cool and dry conditions were associated with a decreased risk of DON accumulation. A prediction model, including only pre-flowering weather conditions, adequately forecasted risk of DON contamination in oat, and can aid in decisions about fungicide treatments.

Sammendrag

The proportion of Norwegian wheat used for food has recently been dramatically lower due to both reduced production and poor quality. Furthermore, the Norwegian milling and baking industries have experienced major challenges in utilizing Norwegian wheat due to the instability of factors, such as protein content and gluten functionality, that are of major importance for baking quality. The variation in the wheat quality can itself cause economic losses for the milling and baking industry due to uncertainty in the marketplace. In the same period as a large variation in baking quality was reported in Norwegian wheat, serious contamination of Fusarium spp. and mycotoxins were observed in some grain lots. We have revealed the severe degradation of gluten proteins in some Norwegian wheat samples leading to an almost complete loss in the gluten functionality. The degradation of the gluten appears to be caused by exogenous proteases, and was associated with the presence of Fusarium spp., and their metabolites, and other microorganisms in the wheat. Increased knowledge is needed to establish the cause of the poor gluten functionality and to develop control measures to reduce the amount of poor quality wheat entering the food value chain. In 2014, a new project was established to generate deeper knowledge in the interface between gluten functionality and effects of Fusarium spp. and other microorganism on wheat quality, and to better utilize Norwegian wheat grown in this challenging environment. A metagenomic analysis, designed to identify microorganisms associated with reduced baking quality, has been undertaken. To study the influence of the identified microorganisms and their metabolites on gluten functionality, wheat plants were inoculated with microorganisms, selected based upon the results of the metagenomics study. Fusarium species are among those microorganisms being tested.

Sammendrag

The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in weeds, crop residues, and soil, sampled from a predetermined selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. All the different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence F. langsethiae in oat. Preliminary results show that F. langsethiae DNA may occur in the oat plant before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. More results from this work will be presented at the meeting.

Sammendrag

The plant pathogenic fungus Fusarium langsethiae produces the highly potent mycotoxins HT-2 and T-2. Since these toxins are frequently detected at high levels in oat grain lots, they pose a considerable risk for food and feed safety in Norway, as well as in other north European countries. To reduce the risk of HT-2/T- 2-contaminated grain lots to enter the food and feed chain, it is important to identify factors that influence F. langsethiae infection and mycotoxin development in oats. However, the epidemiology of F. langsethiae is unclear. A three-year survey was performed to reveal more of the life cycle of F. langsethiae and its interactions with oats, other Fusarium species, as well as insects, mites and weeds. We searched for inoculum sources by quantifying the amount of F. langsethiae DNA in weeds, crop residues, and soil, sampled from a predetermined selection of oat-fields. To be able to define the onset of infection, we analysed the amount of F. langsethiae DNA in oat plant material sampled at selected growth stages (between booting and maturation), as well as the amount of F. langsethiae DNA and HT-2 and T-2 toxins in the mature grain. We also studied the presence of possible insect- and mite vectors sampled at the selected growth stages using Berlese funnel traps. All the different types of materials were also analysed for the presence F. graminearum DNA, the most important deoxynivalenol producer observed in Norwegian cereals, and which presence has shown a striking lack of correlation with the presence F. langsethiae in oat. Preliminary results show that F. langsethiae DNA may occur in the oat plant before heading and flowering. Some F. langsethiae DNA was observed in crop residues and weeds, though at relatively low levels. More results from this work will be presented at the meeting.

Sammendrag

Aksfusariose er en utbredt og destruktiv sjukdom i korn. Korn høsta fra angrepne planter kan inneholde soppgifter (mykotoksiner) og derfor være uegnet til mat og fôr. I Fusariumprosjektet ved Bioforsk Plantehelse ønsker vi å kartlegge faktorer som kan ha betydning for angrep av aksfusariose og utvikling av mykotoksiner i kornet.

Sammendrag

For å kunne imøtekomma EU sine krav (som er handheva av Mattilsynet) om å redusera innhaldet av mykotoksin i korn som går til mat og for, jobbar vi på ’Fusariumprosjektet’ på Bioforsk med å etablere ein strategi for identifisering av kontaminerte kornprøver. Denne strategien går blant anna ut på å etablere ei metode for hurtigtesting av eit større antal prøver.

Sammendrag

Målet med dette prosjektet er å utvikle metoder som kan bidra til å redusere risikoen for Fusarium-toksiner i norsk korn. I samarbeid med næringa pågår aktiviteter på to hovedområder: 1 Kartlegging av klimatiske og agronomiske forhold som påvirker angrep av Fusarium og utvikling av mykotoksiner (grunnlag for varsling), samt fokus på dyrkingsteknikk, inkludert sprøyting, som kan redusere risikoen for Fusarium-angrep/toksin-utvikling. 2 Komme fram til analysemetodikk som raskt og rimelig kan måle innhold av mykotoksiner i kornprøver (hurtigmetode) for å identifisere kornpartier med uakseptabelt høyt toksinnivå og dermed avverge at slike partier brukes til mat og fôr.

Sammendrag

Colletotrichum acutatum fins på alle dei viktige frukt- og bærartane våre og på fleire artar av prydplanter og ugras, men gjer størst skade i kirsebær og eple. Soppen er ei utfordring, fordi han har mange vertplanter, kan leva på enkelte plantedelar utan å utvikla symptom og fordi symptoma ofte ikkje vert synlege på fruktene før etter hausting.