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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

Abstract

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.

Abstract

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.

Abstract

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.

Abstract

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.

Abstract

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