Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2015
Sammendrag
Net blotch is a major barley disease in Norway caused by the necrotrophic fungus Drechslera teres leading to yield losses of up to 40%. At present, resistance of Norwegian cultivars is insufficient. The pathogen secretes necrotrophic effectors (NEs) which act as virulence factors in order to gain entry into and nutrients from the host (Liu et al., 2014). NEs cause a hypersensitive response in the presence of corresponding dominant host susceptibility factors. In this study we examine the potential role of NEs and host receptors in explaining susceptibility to net blotch in Norwegian barley. This knowledge together with an understanding of the genetic background of the Norwegian net blotch population will be utilized to speed up resistance breeding. 365 Norwegian D. teres isolates collected from various regions and years, together with a selection of globally collected isolates, will be RADtag genotyped in order to obtain GBS markers to study the genetic diversity, genomic evolution and population structure of the current Norwegian fungal population and to compare it to pathotypes from other countries. Additionally, this data will allow us to perform Genomewide Association Studies (GWAS) to identify potential novel NE genes. Selected isolates and their culture filtrates will be screened for specific reactions against an association mapping panel of ca. 200 mostly Norwegian barley lines and a biparental mapping population (both genotyped with the Illumina barley 9K chip) to characterize novel NE-host susceptibility interactions and to map the corresponding sensitivity loci. Effector protein candidates will be purified and further analysed to verify their effect on disease development.
Sammendrag
This paper investigated the possibility of leaving out the traditional clean-up step in the QuEChERS procedure and analysing non-cleaned extracts from fruit, vegetables and cereals with a combination of gas chromatography-tandem mass spectrometry (GC-MS/MS), back-flush technology and large-volume injection. By using calibration standards in cucumber matrix, recovery and precision were calculated in lettuce, orange and wheat for 109 pesticides at 0.01 and 0.1 mg kg−1 in two sets of samples: one with and one without clean-up. For both spiking levels, 80–82% of the pesticides in the non-cleaned extracts and 80–84% of the pesticides in the cleaned extracts were within the acceptable recovery range of 70–120%. Precision data for both levels showed that 95% of the pesticides in the non-cleaned extracts and 93–95% of the pesticides in the cleaned extracts had RSDs below 20%. Recovery and precision data were determined using a two tailed t-test (p = 0.05). By using calibration standards in the respective matrix, we studied if the non-cleaned calibration standards gave an extra matrix effect compared with the cleaned standards by using the slope from calibration graphs and plotting the calculated extra matrix effect minus 100 for each compound. The results showed that for 79% of the pesticides, the extra matrix effect minus 100 was within the acceptable range of −20% to 20%. Five European Union proficiency tests on rye, mandarin, rice, pear and barley, respectively, from 2010 to 2012 were reanalysed omitting the clean-up step and showed satisfactory results. At least 70 injections of non-cleaned extracts were made without detecting any increased need for maintenance during the experimental period. Analysing non-cleaned QuEChERS extracts of lettuce, orange and wheat are possible under the conditions described in this paper because recovery, precision and specificity showed satisfactory results compared with samples subjected to traditional dispersive clean-up.
Sammendrag
No abstract has been registered
Forfattere
Agnethe ChristiansenSammendrag
No abstract has been registered
Forfattere
Laura Zoratti Laura Jaakola Hely Häggman Lara GiongoSammendrag
No abstract has been registered
Sammendrag
No abstract has been registered
Sammendrag
Elevated nutrient concentrations in streams in the Norwegian agricultural landscape may occur due to faecal contamination. Escherichia coli (E. coli) has been used conventionally as an indicator of this contamination; however, it does not indicate the source of faecal origin. This work describes a study undertaken for the first time in Norway on an application of specific host-associated markers for faecal source tracking of water contamination. Real-time quantitative polymerase chain reaction (qPCR) on Bacteroidales host-specific markers was employed for microbial source tracking (MST) to determine the origin(s) of faecal water contamination. Four genetic markers were used: the universal AllBac (Bacteroidales) and the individual specific markers BacH (humans), BacR (ruminants) and Hor-Bac (horses). In addition, a pathogenicity test was carried out to detect the top seven Shiga toxin-producing E. coli (STEC) serogroups. The ratio between each individual marker and the universal one was used to: (1) normalise the markers to the level of AllBac in faeces, (2) determine the relative abundance of each specific marker, (3) develop a contribution profile for faecal water contamination and (4) elucidate the sources of contamination by highlighting the dominant origin(s). The results of the qPCR MST analyses indicated the actual contributions of humans and animals to faecal water contamination. The pathogenicity test revealed that water samples were STEC positive at a low level, which was in proportion to the concentration of the ruminant marker. The outcomes were verified statistically by coupling the findings of major contamination sources with observations in the field regarding local land use (residential or agricultural). Furthermore, clear correlations between the human marker and E. coli counts as well as the ruminant marker and STEC quantity in faecally contaminated water were observed. The results of this study have the potential to help identify sources of pollution for targeted mitigation of nutrient losses.
Forfattere
Karen A. Alexander Tavis Potts Shirra Freeman Dafna Israel Johan Johansen Demetris Kletou Marte Meland Danilo Pecorino Celine Rebours Maria Rousou Marc ShortenSammendrag
No abstract has been registered
Forfattere
Alice Budai Daniel Rasse Claudia Forte Line Tau Strand Samuel Abiven C. Rumpel Annelene Pengerud Alain Plante M. A. AlexisSammendrag
No abstract has been registered
Sammendrag
No abstract has been registered