Publikasjoner
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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
Leaf blotch diseases in wheat can cause yield losses above 30 %. The necrotrophic fungus Parastagonospora nodorum is the dominating leaf blotch pathogen in Norwegian spring wheat. It has been well documented at the seedling stage that the pathogen produces necrotrophic effectors (NEs) which induces cell death in plants carrying susceptibility genes (Snn), allowing the necrotroph to enter. However, the role of these interactions under field conditions is less researched. In this study, we conducted field experiments with bi-parental and association mapping populations of spring wheat, to investigate the role of NE/Snn in adult plant resistance. The populations have been genotyped with the Illumina 90 K SNP chip, P. nodorum has high genetic diversity and both sexual and asexual reproduction, but the actual adaptation of the pathogen population to cultivars with different levels of resistance is not well studied. We are screening a collection of Norwegian isolates from known host sources to look for differences in NE-frequencies and haplotype distribution. The mapping populations are also inoculated and infiltrated with culture filtrates from single isolates on the seedling stage. Isolates involved in novel interactions will be deepsequenced in order to look for candidate effector genes. Potential effector proteins will be purified by LPC and HPLC to confirm their role in disease development.
Sammendrag
Leaf blotch diseases in wheat can cause yield losses above 30 %. The necrotrophic fungus Parastagonospora nodorum is the dominating leaf blotch pathogen in Norwegian spring wheat. It has been well documented at the seedling stage that the pathogen produces necrotrophic effectors (NEs) which induces cell death in plants carrying susceptibility genes (Snn), allowing the necrotroph to enter. However, the role of these interactions under field conditions is less researched. In this study, we conducted field experiments with bi-parental and association mapping populations of spring wheat, to investigate the role of NE/Snn in adult plant resistance. The populations have been genotyped with the Illumina 90 K SNP chip, P. nodorum has high genetic diversity and both sexual and asexual reproduction, but the actual adaptation of the pathogen population to cultivars with different levels of resistance is not well studied. We are screening a collection of Norwegian isolates from known host sources to look for differences in NE-frequencies and haplotype distribution. The mapping populations are also inoculated and infiltrated with culture filtrates from single isolates on the seedling stage. Isolates involved in novel interactions will be deepsequenced in order to look for candidate effector genes. Potential effector proteins will be purified by LPC and HPLC to confirm their role in disease development.
Forfattere
Anne-Kari Holm Abdelhameed Elameen Benedikte Watne Oliver May Bente Brurberg Inger Sundheim Fløistad Helge Sjursen Lars Olav BrandsæterSammendrag
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Forfattere
Marianne Stenrød Kirsten Tørresen Therese With Berge Andrea Ficke Ole Martin Eklo Anne K. Falk Øgaard Ola Flaten Karen Refsgaard Valborg KvakkestadSammendrag
In Europe there is an on-going process on implementing regulations aimed at reducing pollution from agricultural production systems, i.e. the Water Framework Directive and the Framework Directive for Sustainable Use of Pesticides. At the same time, there is an increasing focus on food security possibly leading to continued intensification of agricultural production with increased use of external inputs, such as pesticides and fertilizers. Application of sustainable production systems can only be achieved if they balance conflicting environmental and economic effects. In Norway, cereal production is of large importance for food security and reduction of soil and phosphorus losses, as well as pesticide use and leaching/runoff in the cereal production are of special concern. Therefore, we need to determine the most sustainable and effective strategies to reduce loss of top soil, phosphorus and pesticides while maintaining cereal yields. A three-year research project, STRAPP, is addressing these concerns. A catchment area dominated by cereal production is our common research arena within STRAPP. Since 1992 a database (JOVA) with data for soil erosion, nutrient and pesticide leaching/runoff (i.e. concentrations in stream water), yield, and agricultural management practices (fertilization, use of pesticides, soil tillage and rotations) has been established for this catchment allowing us to compare a unique diversity in cropping strategies in a defined location. An important part of STRAPP focuses on developing ‘best plant protection strategies’ for cereal fields in the study area, based on field inventories (manual and sensor based) of weeds and common diseases, available forecast systems, and pesticide leaching risk maps. The results of field studies during the growing seasons of 2013 and 2014 will be presented, with a focus on possible integrated pest management (IPM) strategies for weeds and fungal diseases in cereal production. We will also present the project concept and methods for coupling optimized plant protection strategies to (i) modelling of phosphorus and pesticide leaching/runoff, as well as soil loss, and (ii) farm-economic impacts and adaptations. Further, methods for balancing the conflicting environmental and economic effects of the above practices, and the evaluation of instruments for increased adoption of desirable management practices will be outlined.
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