Ingerd Skow Hofgaard
Research Scientist
Biography
Authors
Anne-Grete Roer Hjelkrem Heidi Udnes Aamot Guro Brodal Einar Strand Torfinn Torp Simon G. Edwards Ruth Dill-Macky Ingerd Skow HofgaardAbstract
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.
Authors
Matias Pasquali Marco Beyer Antonio Logrieco Kris Audenaert Virgilio Balmas Ryan Basler Anne-Laure Boutigny Jana Chrpova Elzbieta Czembor Tatiana Gagkaeva María T. González-Jaén Ingerd Skow Hofgaard Nagehan D. Köycü Lucien Hoffmann Jelena Lević Patricia Marin Thomas Miedaner Quirico Migheli Antonio Moretti Marina E. H. Müller Françoise Munaut Päivi Parikka Marine Pallez-Barthel Jonathan Piec Jonathan Scauflaire Barbara Scherm Slavica Stanković Ulf Thrane Silvio Uhlig Adriaan Vanheule Tapani Yli-Mattila Susanne VogelgsangAbstract
No abstract has been registered
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Torfinn Torp M. Jestoi V.M.T. Lattanzio Sonja Klemsdal C. Waalwijk T. van der Lee Guro BrodalAbstract
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.
Authors
Anne-Grete Roer Hjelkrem Torfinn Torp Guro Brodal Heidi Udnes Aamot Einar Strand Berit Nordskog Ruth Dill-Macky Simon G. Edwards Ingerd Skow HofgaardAbstract
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.
Authors
Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Hugh Riley Jafar Razzaghian Vinh Hong Le Anne-Grete Roer Hjelkrem Ruth Dill-Macky Guro BrodalAbstract
No abstract has been registered
Authors
Ingerd Skow Hofgaard Guro Brodal Heidi Udnes Aamot Marit Almvik Aina Lundon Russenes Morten Lillemo Simon Graham EdwardsAbstract
Oat harvested from plants infested with plant pathogenic fungi within the Fusarium head blight (FHB) complex may sometimes contain high levels of mycotoxins, which makes the grain unsuitable for food and feed. Fusarium graminearum, a deoxynivalenol (DON) producer, and Fusarium langsethiae, a T-2 toxin (T2) and HT-2 toxin (HT2) producer, are commonly occurring in Norwegian oats. We have analysed grains of Nordic oat varieties and breeding lines for the content of mycotoxins and DNA of Fusarium species belonging to the FHB disease complex (Hofgaard et al. 2022). The grains were harvested from field trials located in South-East Norway in the years 2011-2020. The ranking of oat varieties according to HT2+T2 levels corresponded with the ranking according to the DNA levels of F. langsethiae. However, this ranking did not resemble the ranking for DON and F. graminearum DNA. Our results implies that a moderate resistance to DON producers does not guarantee a moderate resistance to HT2+T2 producers. Separate tests are therefore necessary to determine the resistance towards DON and HT2+T2 producers in oats. This creates practical challenges for the screening of FHB resistance in oats as todays’ screening focuses on resistance to F. graminearum and DON. We identified oat varieties with generally low levels of both mycotoxins and FHB pathogens which should be promoted to mitigate mycotoxin risk in Norwegian oats.
Authors
Heidi Udnes Aamot Hesam Mousavi Jafar Razzaghian Guro Brodal Michael Sulyok Rudolf Krska Simon G. Edwards Ingerd Skow HofgaardAbstract
In Norway, high levels of mycotoxins are occasionally observed in oat grain lots, and this cause problems for growers, livestock producers and the food and feed industries. Mycotoxins of primary concern are deoxynivalenol (DON) produced by Fusarium graminearum and HT2- and T2-toxins (HT2+T2) produced by Fusarium langsethiae. Although effort has been made to understand the epidemiology of F. langsethiae in oats, this is still not fully understood. In the present study, we aimed to increase our understanding of the F. langsethiae – oat interaction. Resistance to F. langsethiae was studied in three oat varieties after inoculation at early (booting, heading, flowering) or late (flowering, milk, dough) growth stages in greenhouse experiments. The oat varieties had previously shown different levels of resistance to F. graminearum: Odal, Vinger (both moderately resistant), and Belinda (susceptible). The levels of F. langsethiae DNA and HT2+T2 in harvested grain were measured, and differences in aggressiveness (measured as the level of F. langsethiae DNA in grain) between F. langsethiae isolates were observed. Substantial levels of F. langsethiae DNA and HT2+T2 were detected in grain harvested from oats that had been spray-inoculated at heading or later growth stages, suggesting that oats are susceptible to F. langsethiae from heading and onwards. Vinger had a moderate resistance to F. langsethiae/HT2+T2, whereas Odal and Belinda were relatively susceptible. We observed that late inoculations resulted in relatively higher levels of trichothecene A metabolites other than HT2+T2 (mostly glycosylated HT-2, and smaller amounts of some other metabolites) in harvested grain, which indicate that infections close to harvest may pose a further risk to food and feed safety.
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Till Seehusen Marit Almvik Guro Brodal Ruth Dill-Macky Simon Graham EdwardsAbstract
In Norway, Fusarium diseases and associated mycotoxin contamination in spring oats occasionally cause problems for growers, livestock producers and the food and feed industries. Besides weather factors, such as rainfall and temperature in the critical periods around flowering and before harvest, inoculum production and disease development are influenced by agricultural practices. The occurrence of Fusarium graminearum and DON in oat grain lots do not generally correlate with that of Fusarium langsethiae and HT-2/T-2-toxins. Therefore, to develop a robust disease management strategy, there is a need to reveal the influence of weather and agricultural practice on disease development in oats for both these fungal species. Through various research projects NIBIO researchers have performed field trials to study the effects of straw management, tillage practice, cultivar, and chemical and biological control treatments on the development of Fusarium spp. and mycotoxins in oats. In particular we have investigated whether the amount of straw residues and tillage practice influences the survival of Fusarium spp. in residues, and the subsequent Fusarium spp. infection of the harvested grains. In addition, Fusarium spp. DNA and mycotoxin content (DON and HT-2/T-2) have been analysed in oats from current official cultivar trials. This work has been a collaboration between NIBIO and the Norwegian Agricultural Extension Service. Results will be presented on the Fusarium spp. and mycotoxin contamination of grains harvested from oats grown under various agricultural practices. High incidence of Fusarium avenaceum are often observed in harvested grains as well as straw residues. Fusarium graminearum is also commonly detected. Despite the high concentrations of F. langsethiae DNA and HT-2/T-2 toxins sometimes recorded in oat grain, only low levels of F. langsethiae have been detected in crop residues and air samples. We speculate that the life cycle of F. langsethiae differs from those of F. graminearum and F. avenaceum with regards to survival, inoculum production and dispersal.
Authors
Ingerd Skow Hofgaard Guro Brodal Marit Almvik Morten Lillemo Aina Lundon Russenes Simon Graham Edwards Heidi Udnes AamotAbstract
Over recent decades, the Norwegian cereal industry has had major practical and financial challenges associated with the occurrence of Fusarium head blight (FHB) pathogens and their associated mycotoxins in cereal grains. Deoxynivalenol (DON) is one of the most common Fusarium-mycotoxins in Norwegian oats, however T-2 toxin (T2) and HT-2 toxin (HT2) are also commonly detected. The aim of our study was to rank Nordic spring oat varieties and breeding lines by content of the most commonly occurring Fusarium mycotoxins (DON and HT2 + T2) as well as by the DNA content of their respective producers. We analyzed the content of mycotoxins and DNA of seven fungal species belonging to the FHB disease complex in grains of Nordic oat varieties and breeding lines harvested from oat field trials located in the main cereal cultivating district in South-East Norway in the years 2011–2020. Oat grains harvested from varieties with a high FHB resistance contained on average half the levels of mycotoxins compared with the most susceptible varieties, which implies that choice of variety may indeed impact on mycotoxin risk. The ranking of oat varieties according to HT2 + T2 levels corresponded with the ranking according to the DNA levels of Fusarium langsethiae, but differed from the ranking according to DON and Fusarium graminearum DNA. Separate tests are therefore necessary to determine the resistance towards HT2 + T2 and DON producers in oats. This creates practical challenges for the screening of FHB resistance in oats as today’s screening focuses on resistance to F. graminearum and DON. We identified oat varieties with generally low levels of both mycotoxins and FHB pathogens which should be preferred to mitigate mycotoxin risk in Norwegian oats.
Abstract
No abstract has been registered
Authors
Heidi Udnes Aamot Hesam Mousavi Jafar Razzaghian Guro Brodal Michael Sulyok Rudolf Krska Simon G. Edwards Ingerd Skow HofgaardAbstract
No abstract has been registered
Authors
Heidi Udnes Aamot Simeon Rossmann Erik Lysøe Guro Brodal Birgitte Henriksen Ruth Dill-Macky Carl Gunnar Fossdal Ingerd Skow HofgaardAbstract
We used metabarcoding of ITS 1 and 2 to compare the mycobiome of Norwegian spring wheat seed lots of two commonly grown spring wheat varieties (Mirakel and Zebra) harvested in 2016 and 2017. The seed lots varied in germination and were grouped according to high and low germination (≥90% and <90% germinated seeds, respectively) determined by the ISTA germination method. In addition, the percentage of each seed lot infested by the most important wheat pathogens (Microdochium spp., Fusarium spp., and Parastagonospora nodorum) was determined using a plate-out test on PDA, and species-specific qPCR was used to quantify the amount of DNA of F. avenaceum, F. culmorum, F. graminearum, F. poae, M. majus, M. nivale, and P. nodorum. Our study indicated that the presence of Microdochium was most associated with poor germination (which is as expected), while P. nodorum; although present at relatively high levels, apparently had limited impact on germination. Among the species quantified by qPCR, M. majus was the most abundant, F. avenaceum was detected at low levels, whereas the other fusaria were barely detected. Metabarcoding data indicated a negative association between the presence of the fungal genus Neoascochyta and germination, while Pyrenophora and Alternaria species appeared positively associated with germination. Our results indicated some co-existence patterns between fungal species, including both pathogenic and non-pathogenic species, with some species combinations associated with the germination potential of wheat seed.
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Till Seehusen Børge Holen Hugh Riley Ruth Dill-Macky Simon G. Edwards Guro BrodalAbstract
Frequent occurrences of high levels of Fusarium mycotoxins have been recorded in Norwegian oat grain. To elucidate the influence of tillage operations on the development of Fusarium and mycotoxins in oat grain, we conducted tillage trials with continuous oats at two locations in southeast Norway. We have previously presented the content of Fusarium DNA detected in straw residues and air samples from these fields. Grain harvested from ploughed plots had lower levels of Fusarium langsethiae DNA and HT-2 and T-2 toxins (HT2 + T2) compared to grain from harrowed plots. Our results indicate that the risk of F. langsethiae and HT2 + T2 contamination of oats is reduced with increasing tillage intensity. No distinct influence of tillage on the DNA concentration of Fusarium graminearum and Fusarium avenaceum in the harvested grain was observed. In contrast to F. graminearum and F. avenaceum, only limited contents of F. langsethiae DNA were observed in straw residues and air samples. Still, considerable concentrations of F. langsethiae DNA and HT2 + T2 were recorded in oat grain harvested from these fields. We speculate that the life cycle of F. langsethiae differs from those of F. graminearum and F. avenaceum with regard to survival, inoculum production and dispersal.
Authors
Anne-Grete Roer Hjelkrem Heidi Udnes Aamot Morten Lillemo Espen Sannes Sørensen Guro Brodal Aina Lundon Russenes Simon G. Edwards Ingerd Skow HofgaardAbstract
Fusarium graminearum is regarded as the main deoxynivalenol (DON) producer in Norwegian oats, and high levels of DON are occasionally recorded in oat grains. Weather conditions in the period around flowering are reported to have a high impact on the development of Fusarium head blight (FHB) and DON in cereal grains. Thus, it would be advantageous if the risk of DON contamination of oat grains could be predicted based on weather data. We conducted a functional data analysis of weather-based time series data linked to DON content in order to identify weather patterns associated with increased DON levels. Since flowering date was not recorded in our dataset, a mathematical model was developed to predict phenological growth stages in Norwegian spring oats. Through functional data analysis, weather patterns associated with DON content in the harvested grain were revealed mainly from about three weeks pre-flowering onwards. Oat fields with elevated DON levels generally had warmer weather around sowing, and lower temperatures and higher relative humidity or rain prior to flowering onwards, compared to fields with low DON levels. Our results are in line with results from similar studies presented for FHB epidemics in wheat. Functional data analysis was found to be a useful tool to reveal weather patterns of importance for DON development in oats.
Abstract
No abstract has been registered
Abstract
Leaf blotch diseases (LBD), such as Septoria nodorum bloch (Parastagnospora nodorum), Septoria tritici blotch (Zymoseptoria tritici) and Tan spot (Pyrenophora tritici-repentis) can cause severe yield losses (up to 50%) in Norwegian spring wheat (Triticum aestivum) and are mainly controlled by fungicide applications. A forecasting model to predict disease risk can be an important tool to optimize disease control. The association between specific weather variables and the development of LBD differs between wheat growth stages. In this study, a mathematical model to estimate phenological development of spring wheat was derived based on sowing date, air temperature and photoperiod. Weather factors associated with LBD severity were then identified for selected phenological growth stages by a correlation study of LBD severity data (17 years). Although information regarding host resistance and previous crop were added to the identified weather factors, two purely weather-based risk prediction models (CART, classification and regression tree algorithm) and one black box model (KNN, based on K nearest neighbor algorithm) were most accurate to predict moderate to high LBD severity (>5% infection). The predictive accuracy of these models (76–83%) was compared to that of two existing models used in Norway and Denmark (60 and 61% accuracy, respectively). The newly developed models performed better than the existing models, but still had the tendency to overestimate disease risk. Specificity of the new models varied between 49 and 74% compared to 40 and 37% for the existing models. These new models are promising decision tools to improve integrated LBD management of spring wheat in Norway.
Authors
Ingerd Skow Hofgaard Morten Lillemo Heidi Udnes Aamot Marit Almvik Espen Sannes Sørensen Trond Buraas Bernd Rodemann Simon G. Edwards Guro BrodalAbstract
Occasionally, high mycotoxin levels are observed in Norwegian oat grain lots. The development of oat varieties with improved resistance to Fusarium and mycotoxins is therefore highly valued in order to increase the share of high quality grain into the food and feed industry. The Norwegian project “SafeOats” (2016-2020) aimed to develop resistance-screening methods to facilitate the phase-out of Fusarium-susceptible oat germplasm, as well as to give new insight into the biology of Fusarium langsethiae and HT2+T2 accumulation in oats. In naturally infested as well as in inoculated field trials, the relative ranking of oat varieties according to Fusarium graminearum/DON content did not resemble the ranking according to F. langsethiae/HT2+T2 content. One variety regarded as moderate resistant to Fusarium according to studies of DON content, was susceptible to F. langsethiae and thus at high risk for HT2+T2 contamination. Screening of resistance to F. langsethiae/HT2-T2 should therefore be routinely applied in breeding programs in addition to the already established screening of resistance to F. graminearum/DON. The incidence of F. langsethiae in a selection of oat seed lots used for commercial sowing showed a similar ranking of varieties as in the field trials. On average, the fungus was observed on 5% of the kernels in 168 seed lots tested during 2016-2018. No indication of transmission of F. langsethiae from germinating seed to seedling was found in a study with germination of naturally infected seeds. We investigated whether removing of small kernels by size sorting could be a method to reduce the content of mycotoxins in oat grain. For several of the mycotoxins including HT2+T2, the concentrations were considerably higher in the small kernel fraction compared to unsorted grain. Our results demonstrate that the level of mycotoxins in unprocessed oat grain can be reduced by removing small kernels. 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. The project was financed by The Agriculture and Food Industry Research Funds /Research Council of Norway with support from the industry partners Graminor, Lantmännen, Felleskjøpet Agri, Felleskjøpet Rogaland & Agder, Fiskå Mølle Moss, Norgesmøllene, Strand Unikorn/Norgesfôr and Kimen Seed Laboratory.
Authors
Shiori Koga Heidi Udnes Aamot Anne Kjersti Uhlen Till Seehusen Eva Veiseth-Kent Ingerd Skow Hofgaard Anette Moldestad Ulrike BöckerAbstract
This study aims to understand the environmental factors, focusing on rain and fungal infection, affecting the assembly of glutenin polymers during grain maturation. Spring wheat was grown in the field and grains were sampled from 50% grain moisture until maturity. Grain moisture content, protein content, size of glutenin polymers, the presence of proteases, and the amount of DNA from common wheat pathogenic fungi were analysed. Rain influenced the rate of grain desiccation that occurred parallel to the rate of glutenin polymer assembly. Rapid desiccation contributed to faster glutenin polymer assembly than gradual desiccation. Severe reduction in the glutenin polymer size coincided with increased grain moisture due to rain. Furthermore, increased fungal DNA followed by presence of gluten-degrading proteases was observed in the grain after humid conditions. The presence of gluten-degrading proteases was presumably involved in reducing the size of glutenin polymers in grain. Our study gave new insight into how environmental conditions could be associated with the assembly of glutenin polymers during grain maturation. The results suggest that rain and/or fungal proteases play an important role in reducing the molecular size of glutenin polymers.
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Till Seehusen Hugh Riley Ruth Dill-Macky Børge Holen Guro BrodalAbstract
To mitigate the risk of erosion and nutrient runoff, reduced tillage has become more prevalent in Norway. Within within recent decades, there have been some years with relatively high occurrence of Fusarium head blight and mycotoxins in Norwegian cereal grain. This is thought to have been caused by an increased inoculum potential (IP) of Fusarium spp. due to larger amount of crop residues remaining on the soil surface, in combination with weather conditions promoting fungal growth and infection of cereal plants. The objective of this work was to elucidate the influence of different tillage practices on the IP of Fusarium spp. and the subsequent Fusarium-infection and mycotoxin contamination of spring wheat grain at harvest. Tillage trials were conducted at two locations in southeast Norway (Solør and Toten) over three years, 2010-2012. Residues of wheat from the previous year were collected in spring. Fusarium avenaceum and Fusarium graminearum were the most common Fusarium species recorded on wheat straw residues. IP was calculated as the percentage of the residues infested with Fusarium spp. multiplied by the proportion of the soil surface covered with residues. The IP of Fusarium spp. was lower in ploughed plots compared to those tilled with harrowing only. Ploughing in spring resulted in a similarly low IP as autumn ploughing. In contrast, harrowing in autumn generally reduced IP more than did spring harrowing. The mycotoxin levels in the harvested wheat were generally low, except for deoxynivalenol at high levels in Solør 2011. Despite a lower IP of ploughed versus harrowed plots, this was not reflected in the content of Fusarium and mycotoxins in harvested grain. The Fusarium species that dominated in the residues examined in this study were the same as those detected in the harvested grain, supporting the finding that residues are an important source of inoculum.
Abstract
No abstract has been registered
Authors
Heidi Udnes Aamot Erik Lysøe Shiori Koga Katherine Ann Gredvig Nielsen Ulrike Böcker Guro Brodal Ruth Dill-Macky Anne Kjersti Uhlen Ingerd Skow HofgaardAbstract
The bread-making quality of wheat depends on the viscoelastic properties of the dough in which gluten proteins play an important role. The quality of gluten proteins is influenced by the genetics of the different wheat varieties and environmental factors. Occasionally, a near complete loss of gluten strength, measured as the maximum resistance towards stretching (Rmax), is observed in grain lots of Norwegian wheat. It is hypothesized that the loss of gluten quality is caused by degradation of gluten proteins by fungal proteases. To identify fungi associated with loss of gluten strength, samples from a selection of wheat grain lots with weak gluten (n = 10, Rmax < 0.3 N) and strong gluten (n = 10, Rmax ≥ 0.6 N) was analyzed for the abundance of fungal operational taxonomic units (OTUs) using DNA metabarcoding of the nuclear ribosomal Internal Transcribed Spacer (ITS) region ITS1. The DNA quantities for a selection of fungal pathogens of wheat, and the total amount of fungal DNA, were analyzed by quantitative PCR (qPCR). The mean level of total fungal DNA was higher in grain samples with weak gluten compared to grain samples with strong gluten. Heightened quantities of DNA from fungi within the Fusarium Head Blight (FHB) complex, i.e. Fusarium avenaceum, Fusarium graminearum, Microdochium majus, and Microdochium nivale, were observed in grain samples with weak gluten compared to those with strong gluten. Microdochium majus was the dominant fungus in the samples with weak gluten. Stepwise regression modeling based on different wheat quality parameters, qPCR data, and the 35 most common OTUs revealed a significant negative association between gluten strength and three OTUs, of which the OTU identified as M. majus was the most abundant. The same analysis also revealed a significant negative relationship between gluten strength and F. avenaceum detected by qPCR, although the DNA levels of this fungus were low compared to those of M. majus. In vitro growth rate studies of a selection of FHB species showed that all the tested isolates were able to grow with gluten as a sole nitrogen source. In addition, proteins secreted by these fungi in liquid cultures were able to hydrolyze gluten substrate proteins in zymograms, confirming their capacity to secrete gluten-degrading proteases. The identification of fungi with potential to influence gluten quality can enable the development of strategies to minimize future problems with gluten strength in food-grade wheat.
Authors
Mohamed Ibrahim Mohamed Abdelhalim May Bente Brurberg Ingerd Skow Hofgaard Odd Arne Rognli Anne Marte TronsmoAbstract
Microdochium majus and Microdochium nivale cause serious disease problems in grasses and cereal crops in the temperate regions. Both fungi can infect the plants during winter (causing pink snow mould) as well as under cool humid conditions during spring and fall. We conducted a pathogenicity test of 15 M. nivale isolates and two M. majus isolates from Norway at low temperature on four different grass cultivars of Lolium perenne and Festulolium hybrids. Significant differences between M. nivale isolates in the ability to cause pink snow mould were detected. The M. nivale strains originally isolated from grasses were more pathogenic than isolates from cereals. The genetic diversity of M. nivale and M. majus isolates was studied by sequencing four genetic regions; Elongation factor-1 alpha (EF-1α), β-tubulin, RNA polymerase II (RPB2) and the Internal Transcribed Spacer (ITS). Phylogenetic trees based on the sequences of these four genetic regions resolved M. nivale and M. majus isolates into separate clades. Higher genetic diversity was found among M. nivale isolates than among M. majus isolates. M. nivale isolates revealed genetic differences related to different host plants (grasses vs. cereals) and different geographic regions (Norway and UK vs. North America). Sequence results from the RPB2 and β-tubulin genes were more informative than those from ITS and EF-1α. The genetic and phenotypic differences detected between Norwegian M. nivale isolates from cereals and grasses support the assumption that host specialization exist within M. nivale isolates.
Abstract
Cereal grain contaminated by Fusarium mycotoxins is undesirable in food and feed because of the harmful health effects of the mycotoxins in humans and animals. Reduction of mycotoxin content in grain by cleaning and size sorting has mainly been studied in wheat. We investigated whether the removal of small kernels by size sorting could be a method to reduce the content of mycotoxins in oat grain. Samples from 24 Norwegian mycotoxin-contaminated grain lots (14 from 2015 and 10 from 2018) were sorted by a laboratory sieve (sieve size 2.2 mm) into large and small kernel fractions and, in addition to unsorted grain samples, analyzed with LC-MS-MS for quantification of 10 mycotoxins. By removing the small kernel fraction (on average 15% and 21% of the weight of the samples from the two years, respectively), the mean concentrations of HT-2+T-2 toxins were reduced by 56% (from 745 to 328 µg/kg) in the 2015 samples and by 32% (from 178 to 121 µg/kg) in the 2018 samples. Deoxynivalenol (DON) was reduced by 24% (from 191 to 145 µg/kg) in the 2018 samples, and enniatin B (EnnB) by 44% (from 1059 to 594 µg/kg) in the 2015 samples. Despite low levels, our analyses showed a trend towards reduced content of DON, ADON, NIV, EnnA, EnnA1, EnnB1 and BEA after removing the small kernel fraction in samples from 2015. For several of the mycotoxins, the concentrations were considerably higher in the small kernel fraction compared to unsorted grain. Our results demonstrate that the level of mycotoxins in unprocessed oat grain can be reduced by removing small kernels. We assume that our study is the first report on the effect of size sorting on the content of enniatins (Enns), NIV and BEA in oat grains.
Authors
Morten Lillemo Selamawit Tekle Espen Sannes Sørensen Trond Buraas Heidi Udnes Aamot Ingerd Skow Hofgaard Bernd Rodemann Alf Ceplitis Helge Skinnes Åsmund BjørnstadAbstract
No abstract has been registered
Authors
Heidi Udnes Aamot Katherine Ann Gredvig Nielsen Shiori Koga Anne Kjersti Uhlen Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Ingerd Skow HofgaardAbstract
No abstract has been registered
Abstract
Complex communities of microorganisms influence plant and agroecosystem health and productivity. Bacteria and fungi constitute a major part of the wheat head microbiome. A microorganism’s ability to colonize or infect a wheat seed is influenced by interacting microbiome. In Norway, wheat seed lots are routinely analysed for the infestation by Fusarium head blight and seedling blight diseases, such as Fusarium and Microdochium spp., and glume blotch caused by Parastagonospora nodorum using traditional methods (plating grain on PDA, recording presence or absence of fungal colonies) The purpose is to decide if the seed quality is suitable for sowing and whether seed treatment is needed. This method is time consuming, require knowledge within fungal morphology, and do not facilitate identification to species level in all cases. Molecular methods such as sequencing could allow detection and quantification of “all” microbial DNA, only limited by the specificity of the primers. Microbial profiling (metabarcoding) can be very time and cost-effective, since a mixture of many samples can be analysed simultaneously for both fungi and bacteria, and other microbes if required. In our project “Phytobiome” we used metabarcoding to analyse microbial communities in wheat heads and verify this information with results from qPCR and plate studies for a more complete study. Around 150 spring wheat seed lots from the years 2016-2017 (including two cultivars) were selected for analysis. One of the main objectives was to find microorganisms associated with seed germination. We will present findings from this work, but also some challenges when using PCR-based sequencing methods, especially regarding Fusarium head blight fungi.
Abstract
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Abstract
The SafeOats project was initiated in 2016. An important objective of this project is to develop resistance screening methods to facilitate the phase-out of Fusarium-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 relative ranking of oat varieties according to F. graminearum/DON versus F. langsethiae/HT2+T2 content has been explored in field and greenhouse trials. In the greenhouse studies, we have analysed the content of Fusarium DNA and mycotoxins in grains of selected oat varieties inoculated at different development stages. Furthermore, we are currently studying the transcriptome during F. langsethiae and F. graminearum infestation of oats. The project also focus on the occurrence of F. langsethiae in oat seeds and possible influence of the fungus on seedling development in a selection of oat varieties. SafeOats is coordinated by NIBIO and is a collaboration between NIBIO, NMBU, Kimen Seed Laboratory, and the main Norwegian and Swedish breeding companies, Graminor and Lantmännen. Harper Adam University (UK) and Julius Kühn-Institute (Germany) are international collaborators. The project 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, Felleskjøpet Agri, Felleskjøpet Rogaland & Agder, Fiskå Mølle Moss, Norgesmøllene, Strand Unikorn/Norgesfôr and Kimen Seed Laboratory. 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.
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Morten Lillemo Guro Brodal Erik Lysøe Marit Almvik Anne-Grete Roer Hjelkrem Mauritz Åssveen Aina Lundon Russenes Einar Strand Åsmund Bjørnstad Helge Skinnes Selamawit Tekle Espen Sannes Sørensen Trond Buraas Alf Ceplitis Birgitte Henriksen Bernd Rodemann Simon G. EdwardsAbstract
Occasionally, high mycotoxin levels are observed in Norwegian oat grain lots. The development of moderate resistant oat cultivars is therefore highly valued in order to increase the share of high quality grain into the food and feed industry. The Norwegian SafeOats project (2016-2020) aims to develop resistance screening methods to facilitate the phase-out of Fusarium-susceptible oat germplasm. Furthermore, SafeOats will give new insight into the biology of F. langsethiae and HT2+T2 accumulation in oats. The relative ranking of oat varieties according to F. graminearum/DON versus F. langsethiae/HT2+T2 content has been explored in naturally infested as well as in inoculated field trials. Routine testing of the resistance to F. graminearum in oat cultivars and breeding lines has been conducted in Norway since 2007. We are currently working on ways to scale up the inoculum production and fine tune the methodology of F. langsethiae inoculation of field trials to be routinely applied in breeding programs. Through greenhouse studies, we have analysed the content of Fusarium DNA and mycotoxins in grains of selected oat varieties inoculated at different development stages. Furthermore, we are studying the transcriptome during F. langsethiae and F. graminearum infestation of oats. The project also focus on the occurrence of F. langsethiae in oat seeds and possible influence of the fungus on seedling development in a selection of oat varieties. On average, the fungus was observed on 5% of the kernels in 168 seed lots tested during 2016-2018. No indication of transmission of F. langsethiae from germinating seed to seedlings was found in a study with germination of naturally infected seeds. So far, the studies have shown that the ranking of oat varieties according to HT2+T2 content in non-inoculated field trials resembles the ranking observed in inoculated field trials. The ranking of oat varieties according to DON content is similar in non-inoculated and F. graminearum inoculated field trials. However, the ranking of oat varieties according to DON content does not resemble the ranking for HT2+T2. 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. The project 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, Felleskjøpet Agri, Felleskjøpet Rogaland & Agder, Fiskå Mølle Moss, Norgesmøllene, Strand Unikorn/Norgesfôr and Kimen Seed Laboratory.
Authors
Heidi Udnes Aamot Katherine Ann Gredvig Nielsen Shiori Koga Anne Kjersti Uhlen Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Ingerd Skow HofgaardAbstract
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.
Abstract
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Authors
Anne-Grete Roer Hjelkrem Heidi Udnes Aamot Guro Brodal Einar Strand Torfinn Torp Simon G. Edwards Ruth Dill-Macky Ingerd Skow HofgaardAbstract
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.
Abstract
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.
Abstract
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Abstract
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Authors
Heidi Udnes Aamot Ingeborg Klingen Simon Edwards May Bente Brurberg Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa Gauslaa Ingerd Skow HofgaardAbstract
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.
Authors
Anne-Grete Roer Hjelkrem Torfinn Torp Einar Strand Guro Brodal Heidi Udnes Aamot Berit Nordskog Ruth Dill-Macky Simon G. Edwards Ingerd Skow HofgaardAbstract
No abstract has been registered
Authors
Anne-Grete Roer Hjelkrem Heidi Udnes Aamot Guro Brodal Einar Strand Torfinn Torp Ruth Dill-Macky Simon G. Edwards Berit Nordskog Ingerd Skow HofgaardAbstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
We present the complete genome sequence of Luteibacter rhizovicinus type strain LJ96T, a yellow-pigmented gammaproteobacterium isolated from the rhizosphere of barley (Hordeum vulgare) Johansen et al. (2005) , a species with numerous potential applications. The genome sequence was deposited to NCBI GenBank with the accession number CP017480.
Authors
K.A.G Nielsen Ingerd Skow Hofgaard Shiori Koga H.U. Aamot Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Anne Kjersti UhlenAbstract
No abstract has been registered
Authors
Alemayehu Getachew Assefa Alemayehu Chala Ingerd Skow Hofgaard May Bente Brurberg Michael Sulyok Anne Marte TronsmoAbstract
The natural occurrence of fungi, mycotoxins and fungal metabolites was investigated in 100 samples of maize grains collected from south and southwestern Ethiopia in 2015. The maize samples were contaminated by Fusarium, Aspergillus and Penicillium species. Using liquid chromatography tandem mass spectrometry 127 secondary metabolites were analysed. Zearalenone was the most prevalent mycotoxin, occurring in about 96% of the samples. Zearalenone sulfate was the second most prevalent, present in 81% of the samples. Fumonisin B1 was detected in 70% of the samples with a mean level of 606 μg kg−1 in positive samples, while FB2, FB3 and FB4 were detected in 62%, 51% and 60% of the maize samples with mean levels of 202, 136 and 85 μg kg−1, respectively. Up to 8% of the samples were contaminated with aflatoxins, with a maximum level of aflatoxin B1 of 513 μg kg−1. Results were higher than earlier reports for maize from Ethiopia.
Abstract
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.
Authors
Heidi Udnes Aamot Ingeborg Klingen Simon G. Edwards May Bente Brurberg Guro Brodal Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa Gauslaa Ingerd Skow HofgaardAbstract
No abstract has been registered
Authors
Matias Pasquali Marco Beyer Antonio Logrieco Kris Audenaert Virgilio Balmas Ryan Basler Anne-Laure Boutigny Jana Chrpova Elzbieta Czembor Tatiana Gagkaeva María T. González-Jaén Ingerd Skow Hofgaard Nagehan D. Köycü Lucien Hoffmann Jelena Lević Patricia Marin Thomas Miedaner Quirico Migheli Antonio Moretti Marina E. H. Müller Françoise Munaut Päivi Parikka Marine Pallez-Barthel Jonathan Piec Jonathan Scauflaire Barbara Scherm Slavica Stanković Ulf Thrane Silvio Uhlig Adriaan Vanheule Tapani Yli-Mattila Susanne VogelgsangAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Ingerd Skow Hofgaard Heidi Udnes Aamot Torfinn Torp M. Jestoi V.M.T. Lattanzio Sonja Klemsdal C. Waalwijk T. van der Lee Guro BrodalAbstract
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.
Authors
Anne-Grete Roer Hjelkrem Torfinn Torp Guro Brodal Heidi Udnes Aamot Einar Strand Berit Nordskog Ruth Dill-Macky Simon G. Edwards Ingerd Skow HofgaardAbstract
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.
Authors
Mallikarjuna Rao Kovi Mohamed Abdelhalim Anil Kunapareddy Åshild Ergon Anne Marte Tronsmo May Bente Brurberg Ingerd Skow Hofgaard Torben Asp Odd Arne RognliAbstract
Lack of resistance to pink snow mould (Microdochium nivale) is a major constraint for adaptation of perennial ryegrass (Lolium perenne L.) to continental regions with long-lasting snow cover at higher latitudes. Almost all investigations of genetic variation in resistance have been performed using cold acclimated plants. However, there may be variation in resistance mechanisms that are functioning independently of cold acclimation. In this study our aim was to identify candidate genes involved in such resistance mechanisms. We first characterized variation in resistance to M. nivale among non-acclimated genotypes from the Norwegian cultivar ‘Fagerlin’ based on relative regrowth and fungal quantification by real-time qPCR. One resistant and one susceptible genotype were selected for transcriptome analysis using paired-end sequencing by Illumina Hiseq 2000. Transcriptome profiles, GO enrichment and KEGG pathway analysis indicate that defense response related genes are differentially expressed between the resistant and the susceptible genotype. A significant up-regulation of defense related genes, as well as genes involved in cell wall cellulose metabolic processes and aryl-alcohol dehydrogenase (NADP+) activity, was observed in the resistant genotype. The candidate genes identified in this study might be potential molecular marker resources for breeding perennial ryegrass cultivars with improved resistance to pink snow mould.
Authors
Silvio Uhlig Ana Stanic Ingerd Skow Hofgaard Bernhard Kluger Rainer Schuhmacher Christopher Owen MilesAbstract
A glutathione (GSH) adduct of the mycotoxin 4-deoxynivalenol (DON), together with a range of related conjugates, has recently been tentatively identified by LC-MS of DON-treated wheat spikelets. In this study, we prepared samples of DON conjugated at the 10- and 13-positions with GSH, Cys, CysGly, -GluCys and N-acetylcysteine (NAC). The mixtures of conjugates were used as standards for LC-HRMS analysis of one of the DON-treated wheat spikelet samples, as well as 19 Norwegian grain samples of spring wheat and 16 grain samples of oats that were naturally-contaminated with DON at concentrations higher than 1 mg/kg. The artificially-contaminated wheat spikelets contained conjugates of GSH, CysGly and Cys coupled at the olefinic 10-position of DON, whereas the naturally-contaminated harvest-ripe grain samples contained GSH, CysGly, Cys, and NAC coupled mainly at the 13-position on the epoxy group. The identities of the conjugates were confirmed by LC-HRMS comparison with authentic standards, oxidation to the sulfoxides with hydrogen peroxide, and examination of product-ion spectra from LC-HRMS/MS analysis. No -GluCys adducts of DON were detected in any of the samples. The presence of 15-O-acetyl-DON was demonstrated for the first time in Norwegian grain. The results indicate that a small but significant proportion of DON is metabolized via the GSH-conjugation pathway in plants. To our knowledge, this is the first report of in vivo conjugation of trichothecenes via their epoxy group, which has generally been viewed as unreactive. Because conjugation at the 13-position of DON and other trichothecenes has been shown to be irreversible, this type of conjugate may prove useful as a biomarker of exposure to DON and other 12,13-epoxytrichothecenes.
Abstract
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Authors
Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Hugh Riley Jafar Razzaghian Vinh Hong Le Anne-Grete Roer Hjelkrem Ruth Dill-Macky Guro BrodalAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Ingerd Skow Hofgaard Shiori Koga Heidi Udnes Aamot Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Anne Kjersti UhlenAbstract
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.
Abstract
This paper presents peer-reviewed studies comparing the content of deoxynivalenol (DON), HT-2+T-2 toxins, zearalenone (ZEA), nivalenol (NIV), ochratoxin A (OTA) and fumonisins in cereal grains, and patulin (PAT) in apple and apple-based products, produced in organically and conventionally grown crops in temperate regions. Some of the studies are based on data from controlled field trials, however, most are farm surveys and some are food basket surveys. Almost half of the studies focused on DON in cereals. The majority of these studies found no significant difference in DON content in grain from the two farming systems, but several studies showed lower DON content in organically than in conventionally produced cereals. A number of the investigations reported low DON levels in grain, far below the EU limits for food. Many authors suggested that weather conditions, years, locations, tillage practice and crop rotation are more important for the development of DON than the type of farming. Organically produced oats contained mainly lower levels of HT-2+T-2 toxins than conventionally produced oats. Most studies on ZEA reported no differences between farming systems, or lower concentrations in organically produced grain. For the other mycotoxins in cereals, mainly low levels and no differences between the two farming systems were reported. Some studies showed higher PAT contamination in organically than in conventionally produced apple and apple products. The difference may be due to more efficient disease control in conventional orchards. It cannot be concluded that any of the two farming systems increases the risk of mycotoxin contamination. Despite no use of fungicides, an organic system appears generally able to maintain mycotoxin contamination at low levels. More systematic comparisons from scientifically controlled field trials and surveys are needed to clarify if there are differences in the risk of mycotoxin contamination between organically and conventionally produced crops.
Abstract
Four field trials (spring wheat and oats) were conducted (one on clay soil, one on loam soil and two on silt soil) for three years in important cereal growing districts, to investigate the influence of tillage regimes (ploughing versus reduced tillage in either autumn or spring) and straw management (removed and retained) on plant residue amounts, weed populations, soil structural parameters and cereal yields. The effect of tillage on soil structure varied, mainly due to the short trial period. In general, the amount of small soil aggregates increased with tillage intensity. Reduced soil tillage, and in some cases spring ploughing, gave significantly higher aggregate stability than autumn ploughing, thus providing protection against erosion. However, decreasing tillage intensity increased the amounts of weeds, particularly of Poa annua on silt soil. Straw treatment only slightly affected yields, while effects of tillage varied between both year and location. Reduced tillage, compared to ploughing, gave only small yield differences on loam soil, while it was superior on clay soil and inferior on silt soil. Our results suggest that shallow spring ploughing is a good alternative to autumn ploughing, since it gave comparable yields, better protection against erosion and was nearly as effective against weeds.
Abstract
No abstract has been registered
Authors
Heidi Udnes Aamot Ingeborg Klingen SG Edwards May Bente Brurberg Guro Brodal Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa B. Gauslå Ingerd Skow HofgaardAbstract
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.
Authors
Heidi Udnes Aamot Ingeborg Klingen S.G. Edwards May Bente Brurberg Guro Brodal Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa B. Gauslå Ingerd Skow HofgaardAbstract
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.
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Authors
Matias Pasquali Marco Beyer Antonio Logrieco Kris Audenaert Virgilio Balmas Ryan Basler Anne-Laure Boutigny Jana Chrpova Elżbieta Czembor Tatiana Gagkaeva María Teresa González-Jaén Ingerd Skow Hofgaard Nagehan Desen Köycü Jelena Lević Patricia Marín García Thomas Miedaner Quirico Migheli Antonio Moretti Marina Elsa Herta Müller Françoise Munaut Päivi Parikka Marine Pallez Jonathan Scauflaire Barbara Scherm Slavica Stanković Ulf Thrane Silvio Uhlig Adriaan Vanheule Tapani Yli-Mattila Susanne VogelgsangAbstract
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Authors
Heidi Udnes Aamot Todd J. Ward Guro Brodal Trude Vrålstad Gunnar Bræck Larsen Sonja Klemsdal Abdelhameed Elameen Silvio Uhlig Ingerd Skow HofgaardAbstract
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Authors
Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Jafar Razzaghian Vinh Hong Le Hugh Riley Børge Holen Elisa Gauslaa Hege Særvold Steen Anne-Grete Roer Hjelkrem S.G. Edwards Ruth Dill-Macky Guro BrodalAbstract
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Ingerd Skow Hofgaard Heidi Udnes Aamot Anne-Grete Roer Hjelkrem Mauritz Åssveen Einar Strand Guro BrodalAbstract
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Ingerd Skow Hofgaard Heidi Udnes Aamot Anne-Grete Roer Hjelkrem Mauritz Åssveen Einar Strand Guro BrodalAbstract
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Ingerd Skow Hofgaard Heidi Udnes Aamot Anne-Grete Roer Hjelkrem Mauritz Åssveen Einar Strand Guro BrodalAbstract
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Ingerd Skow HofgaardAbstract
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Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Unni Abrahamsen Jafar Razzaghian Vinh Hong Le Hugh Riley Einar Strand Elisa Gauslaa Mauritz Åssveen May Bente Brurberg Hege Særvold Steen Guro BrodalAbstract
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Authors
Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Unni Abrahamsen Jafar Razzaghian Vinh Hong Le Hugh Riley Einar Strand Elisa Gauslaa Mauritz Åssveen May Bente Brurberg Hege Særvold Steen Guro BrodalAbstract
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Anne Marte Tronsmo Mohamed Abdelhalim May Bente Brurberg Åshild Ergon Ingerd Skow Hofgaard Kovi Mallikarjuna RaoAbstract
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Anne Marte Tronsmo Mohamed Abdelhalim May Bente Brurberg Åshild Ergon Ingerd Skow Hofgaard Kovi Mallikarjuna RaoAbstract
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Silvio Uhlig Gunnar Sundstøl Eriksen Ingerd Skow Hofgaard Rudolf Krska Eduardo Beltrán Michael SulyokAbstract
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Heidi Udnes Aamot May Bente Brurberg Anne Marte Tronsmo Sonja Klemsdal Ingerd Skow Hofgaard Guro BrodalAbstract
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Heidi Udnes Aamot Ingerd Skow Hofgaard Guro Brodal T. Ward Abdelhameed Elameen Trude Vrålstad G. Larsen Per-Erik Clasen Oleif Elen Sonja KlemsdalAbstract
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Ingerd Skow HofgaardAbstract
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Ingerd Skow Hofgaard Till Seehusen Heidi Udnes Aamot Unni Abrahamsen Jafar Razzaghian Vinh Hong Le Hugh Riley Einar Strand Børge Holen Elisa Gauslaa Tove Kristina Sundgren Mauritz Åssveen Berit Nordskog Hege Særvold Steen Guro BrodalAbstract
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Ingerd Skow HofgaardAbstract
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Authors
Aksel Bernhoft Gunnar Sundstøl Eriksen Leif Sundheim Marc Berntssen Anne Lise Brantsæter Guro Brodal Christiane Kruse Fæste Ingerd Skow Hofgaard Trond Rafoss Tore Sivertsen Anne Marte Tronsmo Heidi Amlund Augustine Arukwe Marit Aursand Margaretha Haugen Gro Ingunn Hemre Trond Hofsvang Helle Katrine Knutsen Åshild Krogdahl Jørgen Fredrik Lassen Christer Magnusson Audun Helge Nerland Live Lingaas Nesse Bjørn Næss Einar Ringø Anders Ruus Janneche Utne Skåre Halvor Solheim Arild Sletten Inger-Lise Steffensen Line Charlotte Sverdrup Birger Svihus Ole Torrissen Bente Elisabeth Torstensen Cathrine Thomsen Robin Ørnsrud Bjørn Økland Olav Østerås Jan AlexanderAbstract
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Ingerd Skow HofgaardAbstract
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Mohamed Abdelhalim Åshild Ergon Mallikarjuna Rao Kovi Anil Kunapareddy May Bente Brurberg Ingerd Skow Hofgaard Anne Marte Tronsmo Odd Arne RognliAbstract
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Authors
Heidi Udnes Aamot Ingerd Skow Hofgaard Guro Brodal Oleif Elen M. Jestoi Børge Holen Sonja KlemsdalAbstract
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Abstract
The effect of potential resistance inducing chemicals on disease development of Fusarium head blight was studied in winter wheat (Triticum aestivum L.). As a pre-screening test, the effect of different treatments on development of Microdochium majus (syn. Microdochium nivale var. majus) was studied in detached leaves. Based on these tests, DL-3-aminobutyric acid, Bion (benzo-(1,2,3) thiadiazole-7-carbothioic acid S-methyl ester), and a foliar fertilizer containing potassium phosphite were selected for further studies. Greenhouse-grown winter wheat was sprayed with aqueous solutions of the potential resistance inducers 7 days prior to Fusarium culmorum point inoculation of the heads. Disease development was registered as number of bleached spikelets per inoculated spike. Spraying plants with the foliar fertilizer reduced the disease severity of F. culmorum by up to 40%. A reduced disease development of M. majus was also observed in detached leaves pre-treated with the foliar fertilizer. When the foliar fertilizer was added to the growth medium, a reduced in vitro growth of M. majus and F. culmorum was observed, indicating that the effect on disease development is at least partly due to a fungistatic effect. No significant reduction in disease development was observed in wheat pre-treated with DL-3-aminobutyric acid or Bion, although these compounds tended to reduce disease development, especially when applied in combination with other potential resistance inducers. We conclude that spraying winter wheat with a solution containing potassium phosphite can reduce development of M. majus and F. culmorum.
Abstract
The most important and widespread disease on golf courses is Microdochium nivale. It is a psycrotrophic fungal plant pathogen that is the main cause of biotic winter injury in grasses in the temperate and sub-arctic climates, both with and without snow cover. It is an opportunistic pathogen, with the ability to attack plants under a wide range of environmental conditions. A large variation in both host preference and aggressiveness among isolates has been documented. It is speculated that these traits as well as competition between isolates may be dependent on temperature. The fungus is spread by infected seeds and from infected plants or debris. Besides seed transmitted inoculum, it is not clear whether the primary inoculum source is wind dispersed ascospores or soilborne/plant debris borne inoculum. Wind borne ascospores has been claimed to be the main inoculum source, but perithecia are hardly observed on grasses on Norway. The aim of the present project was obtain better understanding of what is the source of primary inoculum for snow mould caused by M. nivale; to understand how inoculum of M. nivale survives from spring to fall, and from year to year, to understand how climatic conditions affects the potential inoculum by monitoring symptoms on plants, occurrence of the fungus and growth characteristics in vitro of strains sampled from snow melt and through summer and autumn. To obtain such knowledge, surveys and sampling on selected golf courses was conducted. Snow mould symptoms and the occurrence of M. nivale in leaves and stems of grasses sampled from golf greens and foregreens was reduced during the growth season. We also found that M. nivale could be isolated from locations without visible symptoms. Despite a lower isolation rate in autumn, M. nivale was again isolated in some of the originally locations, the following spring. The M. nivale isolation rate was similar from sites located on greens compared to foregreens, and from greens located at more sunny sites compared to more shadowy located greens. We conclude that this fungus seem to survive from year to year within the same locations on greens and foregreens.
Authors
Ingerd Skow Hofgaard Katarzyna Marzec Guro Brodal Birgitte Henriksen May Bente Brurberg Anne-Marte TronsmoAbstract
Microdochium nivale (syn. Microdochium nivale var. nivale) and Microdochium majus (syn. Microdochium nivale var. majus) are important pathogens which cause snow mould on grasses and winter cereals. These fungi are also able to cause leaf blotch of oat and seedling blight, foot rot and ear blight in cereals. Although no distinct differences in the host range of M. nivale and M. majus are found, indications for differences in host preferences between these fungal species have previously been discussed. The culture collection at Bioforsk contains about 250 Microdochium sp. isolated from grasses and cereals over the last 20 years. Most of the isolates collected from leaves of cereals displaying snow mould symptoms in spring, were identified as M. nivale (71 %), whereas most of the isolates collected from cereal seeds (mostly wheat) belong to the species M. majus (92 %). All, except one out of the sixty nine Microdochium sp. isolated from grass leaves were identified as M. nivale (99 %). The relatively higher incidence of M. majus vs. M. nivale on cereal seeds (mostly wheat) harvested in Norway, is in agreement with studies in UK (Parry et al. 1995). Parry et al. suggested that higher natural occurrence of M. majus (vs. M. nivale) on seeds of cereals could be partly due to the higher proportion of M. majus isolates producing perithecia and thus, a relatively higher amount of M. majus spores spreading to the ear (Parry et al. 1995). The high frequency of M. nivale (99 %) vs. M. majus on grasses collected in Norway could indicate that M. nivale is more aggressive on certain grass species. Studies in our lab indeed point towards a higher aggressiveness of M. nivale vs. M. majus on perennial ryegrass at low temperature (2?C) (Hofgaard et al 2006). However, the high incidence of M. nivale on grass leaves could also be caused by differences in temperature preferences, saprophytic ability or ability to infect certain plant parts. Isolates of M. nivale display a higher in vitro growth rate compared to isolates of M. majus at 2?C (Hofgaard et al. 2006). In conclusion, the higher natural occurrence of M. nivale vs. M. majus on turf grasses and the relatively higher aggressiveness of M. nivale on perennial ryegrass could indicate that M. nivale somehow is better adapted to infect certain grass species.
Authors
Guro Brodal Oleif Nilsen Elen Ingerd Skow Hofgaard Heidi Udnes Aamot Erik Lysøe Sonja KlemsdalAbstract
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Authors
Guro Brodal Oleif Nilsen Elen Ingerd Skow Hofgaard Heidi Udnes Aamot Erik Lysøe Sonja KlemsdalAbstract
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Authors
Ingerd Skow Hofgaard Leslie A Wanner Gunhild Hageskal Birgitte Henriksen Sonja Klemsdal Anne Marte TronsmoAbstract
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Abstract
The effect of plant age and cold hardening on resistance to pink snow mould caused by Microdochium nivale was studied in perennial ryegrass. Resistance to M. nivale was estimated as relative regrowth after inoculation and incubation under artificial snow cover at 2 degrees C. Resistance increased with increasing plant age. Cold hardened and unhardened plants of the same age displayed identical resistance. Preliminary studies indicate that expression of genes coding for the PR proteins chitinase and PR-1a increased during incubation of inoculated perennial ryegrass, but no clear difference in expression of these genes was found between plants of different ages, or in hardened versus unhardened plants.
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Authors
Ingerd Skow Hofgaard Birgitte Henriksen Åshild Ergon Helge Skinnes Hilde Kolstad Yalew Tarkegne Anne-Marte TronsmoAbstract
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Authors
Ingerd Skow Hofgaard Birgitte Henriksen Åshild Ergon Hilde Kolstad Helge Skinnes Yalew Tarkegne Anne-Marte TronsmoAbstract
Development of Fusarium head blight (FHB) was studied in winter wheat pre-treated with potential defence activators. Several chemicals were pre-screened for their capacity to reduce development of Microdochium nivale in a detached leaf assay. Selected compounds were further tested for their capacity to reduce Fusarium culmorum development in heads of winter wheat in greenhouse and field experiments. In the detached leaf assay, leaves from plants pre-treated with a foliar fertilizer displayed reduced disease development compared to untreated control. A significantly reduced disease development of FHB in plants pre-treated with the foliar fertilizer was also registered in the greenhouse and field experiments. In the field experiment, harvested grainsfrom plants treated with the foliar fertilizer had up to 75% reduction in Fusarium infected seeds compared to grains from non-treated plants.
Abstract
Wintering ability in the field and resistance to different winter-stress factors under controlled environmental conditions were studied in a full-sib family of perennial ryegrass (Lolium perenne L.). Significant variation in tolerance to freezing and ice encasement, resistance to pink snow mould (Microdochium nivale) and also in winter survival and spring growth were found between the different genotypes. No strong correlations were found between the resistances to the different stress factors. These results indicate that resistance to different winter-stress factors is controlled by separate genes in perennial ryegrass. A low but significant positive correlation was found between spring growth of plants in the field after the first winter and both freezing tolerance and M. nivale resistance measured in controlled environments. Cold hardening seemed to influence freezing tolerance and M. nivale resistance differently in the different genotypes, since no distinct correlation in tolerance to freezing or resistance to M. nivale was found between unhardened and hardened plants. Tolerance or resistance to most of the winter stress factors measured was positively correlated with plant size.
Abstract
The effect of cold acclimation and defence activators on snow mould resistance and expression of pathogenesis-related (PR-) genes were investigated in winter cereals and perennial ryegrass. Cold acclimation, known to induce snow mould resistance, had apotentiating effect on snow mould-induced PR-gene expression in winter wheat. Chitosan treatment induced chitinase expression and in some cases also snow mould resistance in winter wheat. Bion treatment reduced snow mould resistance in perennial ryegrass.
