Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2016
Forfattere
May Bente BrurbergSammendrag
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Forfattere
Isabella BørjaSammendrag
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Forfattere
Torstein KvammeSammendrag
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Forfattere
Ingerd Skow Hofgaard Shiori Koga Heidi Udnes Aamot Ulrike Böcker Erik Lysøe Guro Brodal Ruth Dill-Macky Anne Kjersti UhlenSammendrag
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.
Forfattere
Heidi Udnes Aamot Ingeborg Klingen SG Edwards May Bente Brurberg Guro Brodal Toril Eklo Hege Særvold Steen Jafar Razzaghian Elisa B. Gauslå Ingerd Skow HofgaardSammendrag
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
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Sammendrag
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Sammendrag
The necrotrophic fungus Drechslera teres causes net blotch disease in barley by secreting necrotrophic effectors (NEs) which, in the presence of corresponding host susceptibility factors (SF), act as virulence factors in order to enable host colonization. At present the resistance within most Norwegian cultivars is insufficient. This study aims at detecting QTL associated with resistance and susceptibility in the Nordic barley breeding material and at discovering new NE _ SF interactions. This knowledge together with an understanding of the genetic background of the Norwegian net blotch population will be utilized to speed up resistance breeding. Resistance of a segregating mapping population of a cross between the closely related Norwegian varieties Arve and Lavrans to three Norwegian D. teres isolates was assessed at seedling stage in the greenhouse and in adult plants in the field. QTL mapping revealed four major QTL on chromosomes 4H, 5H, 6H and 7H. The 5H and 6H QTL accounted for up to 47% and 14.1% of the genetic variance, respectively, and were found both in seedlings and adult plants with the latter QTL being an isolate-specific association. The high correlation of seedling and adult resistance (R2=0.49) suggests that components of adult plant resistance can be predicted already at the seedling stage. Selected isolates and their culture filtrates will be screened on selected barley lines to characterize novel NE - SF interactions and to map the corresponding sensitivity loci. Effector protein candidates will be purified and further analysed to verify their effect on disease development. Additionally, 365 Norwegian D. teres isolates and a selection of globally collected isolates are currently being ddRAD genotyped in order to obtain SNP markers to study the genetic diversity and population structure of the current Norwegian fungal population. This data will also allow us to perform Genome Wide Association Studies (GWAS) to identify potential novel NE genes.
Forfattere
Ari Hietala Hugh Cross Halvor Solheim Volkmar Timmermann Nina Elisabeth Nagy Isabella Børja Adam Vivian-Smith Jørn Henrik SønstebøSammendrag
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Sammendrag
Researchers in plant pathology and entomology often study the interaction between a host plant and its pathogen or an insect pest separately. Although studying single pathogen or insect interactions with a host plant is critical to understand the basic infection processes and to model each disease or pest attack separately, this is an extreme simplification of nature’s complexity, where multiple pests and pathogens often appear in parallel and interact with each other and their host plant. Effective management of pests and diseases require understanding of the complex interaction beteween diseases and pests on the host. Under natural conditions, wheat plants are subjected to attack by several insects and pathogens simultaneously or sequentially. The Bird cherry-oat aphid (Rhopalosiphum padi) and the necrotrophic pathogen Parastagonospora nodorum (syn. Stagonospora nodorum) the causal agent of Stagonospora nodorum blotch (SNB) are economically important pests of wheat in Norway. Since they colonize a common host, they may interact directly through competition for resources or indirectly by affecting the host response either positively (induced resistance) or negatively (induced susceptibility or biopredisposition). The effect of aphid infestation on P. nodorum infection and development of the disease could be an important factor in predicting SNB epidemics. However, studies on this multitrophic interactions are scarce. We conducted controlled greenhouse experiments to study the effect of aphid infestation on subsequent SNB development. The wheat cultivar ‘Bjarne’ was treated as follows:1) Aphid infested + insecticide sprayed + P. nodorum inoculated; 2) Insecticide sprayed + P. nodorum inoculated; 3) Water sprayed + P. nodorum inoculated; 4) Control plants (without aphid, insecticide or P. nodorum). When plants were at ca. BBCH 37, 18 adult female aphids (R. padi) were released per pot (treatment 1). Aphid inoculated plants were kept in an insect proof cage in a greenhouse compartment at 20°C, 70% RH, and 16 h photoperiod. Plants for the other treatments were kept in separate insect proof cages in the same greenhouse. Ten days after aphid release, plants infested with aphids (treatment 1) were sprayed with the insecticide BISCAYA (a.i. thiacloprid) at recommended concentration to remove aphids. Plants in treatment 2 and 3 were sprayed with the insecticide and water, respectively. Twenty-four hours after application of the insecticide or water, plants in treatment 1, 2, and 3 were inoculated with P. nodorum spore suspension (106 spores ml-1). The experiment included three replicates and was repeated two times. SNB incidence and severity were recorded. SNB incidence and severity were significantly higher on aphid infested plants than on non-infested plants (P < 0.05). Ten days after P. nodorum inoculation, disease severity were about 3-fold higher on aphid infested plants (treatment 1) than on non-infested plants (treatment 2 and 3). Plants in the blank control (treatment 4) were free of aphids and showed no symptoms of SNB . Infestation of wheat plants by the bird cherry-oat aphid prior to fungal inoculation enhanced the severity of SNB. P. nodorum is a necrotrophic pathogen that lives on nutrients from disintegrated plant cells. The increase in severity of SNB on aphid infested plants could be due to the increased number of dead or dying cells around the aphids feeding sites. However, whether aphids activity induced local or systemic susceptbility to plants is not yet known and needs to be studied further.