Shifts in plant gene expression and corresponding phloem sap components during trilateral interaction of barley (Hordeum vulgare), aphid species (Rhopalosiphum padi) and the aphid-transmitted Barley Yellow Dwarf Virus (BYDV)
Zusammenfassung der Projektergebnisse
Barley yellow dwarf virus (BYDV) is a phloem-limited virus transmitted by aphids. It causes the most economically important virus disease of cereals worldwide. Although the Ryd2 locus mapped on chromosome 3H has been used in resistance breeding in barley and another quantitative trait locus (QTL) has been identified and mapped on chromosome 2H, the mechanisms of tolerance are not well characterized. The intention of the present study was to dissect the reactions of barley cultivars and doubled-haploid lines carrying different tolerance loci in the trilateral interaction of plant, aphid and virus to get insights into the molecular mechanisms of the trilateral interaction. To study the basis of the resistance/tolerance mechanisms in genotypes harboring Ryd2 and/or QTL 2H tolerance alleles a combination of biological, biochemical and molecular methods was applied. Clear differences in reaction to aphid infestation and virus spread between genotypes carrying the QTL 2H or the Ryd2 tolerance alleles were detected. Aphids tried to avoid the cultivar Post carrying the QTL 2H tolerance in choice-tests and aphid feeding led to a significantly higher amount of hypersensitive response (HR) in the mesophyll cells after aphid feeding and a higher amount of collapsed autofluorescent cells (CACs) adjacent to the aphid stylet sheaths compared to the other genotypes, e.g. compared to the tolerant cultivar Vixen carrying a Ryd2 tolerance allele. This suggests that the QTL 2H tolerance allele is involved in aphid resistance whereas the Ryd2 tolerance allele does not exhibit antixenotic or antibiotic effects on aphid feeding. These genotypes also differed in the BYDV accumulation and spread. Cultivar Post showed reduced virus titers in systemically infected leaves whereas cultivar Vixen had similarly high virus titers as the susceptible control indicating different mechanisms of resistance/tolerance in these two cultivars. These differences were also reflected in the global expression profiles of doubled haploid lines carrying the Ryd2 and/or QTL 2H tolerance alleles. Digital gene expression analysis revealed that aphid feeding triggers a broad reaction in all genotypes and leads to a general up-regulation of a large number of stress-related genes, e.g. of genes involved in aphid osmoregulation during phloem feeding. In genotypes with tolerance alleles aphid feeding lead to an up-regulation of genes from the secretory pathway and signalling cascades and was additional enhanced in genotypes with the QTL 2H tolerance alleles including putative insect resistance genes, e.g. thionins. In contrast, the genes that are upregulated upon virus infection and are specific for the Ryd2 tolerance allele include RNA recognition motif containing proteins, endoribonuclease proteins, ribosomal proteins, zinc finger proteins and retrotransposon proteins. The nature of these genes suggest that the presence of the Ryd2 tolerance allele does not result upon virus infection in the up-regulation of specific pathways involved in virus resistance, but rather in a general transcriptional activation and protein metabolic activity. This is consistent with a virus tolerance mechanism where the plant compensates negative effects of virus multiplication by up-regulation of diverse house-keeping genes. In summary, the study has shown that Ryd2 and QTL 2H tolerance alleles in barley are involved in different BYDV-tolerance and R. padi-resistance mechanisms. The study has helped to identify genes that are putative resistance factors which will allow to characterize the differences in the tolerance/resistance mechanisms in more detail and to develop markers for targeted resistance breeding.
Projektbezogene Publikationen (Auswahl)
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2007. Protein shifts in the phloem stream as a response to fungal infection in Hordeum vulgare? 3rd internationale Rauischholzhausen Conference, DFG Forschergruppe 666, Rauischholzhausen
Knauer T, Steckbauer K, van Bel AJE
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2008. A combinatory approach for analysis of protein sets in barley sievetube samples using EDTA-facilitated exudation and aphid stylectomy. J. Plant Physiol. 165, 95-103
Gaupels F, Knauer T, van Bel AJE
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2008. Adaptation of aphid stylectomy for analysis of proteins and RNAs in barley phloem sap. J. Exp. Bot. 59, 3297-3306
Gaupels F, Buhtz A, Knauer T, Desmukh S, Waller W, van Bel AJE, Kogel KH, Kehr J
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2008. Barley Yellow Dwarf Virus detection and assessment of virus spread in susceptible and resistant barley plants. 1st Conference of the International Giessen Graduate School for the Life Sciences
Spamer V, Obermeier C, Friedt W
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2008. Barley Yellow Dwarf Virus detection and assessment of virus spread in susceptible and resistant barley plants. 59th Meeting of Plant Breeders. Gumpenstein/Austria
Spamer V, Obermeier C, Friedt W
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2008. Barley Yellow Dwarf Virus. IFZ Lunch Time Seminar, Research Center for Biosystems, Land Use and Nutrition Giessen
Spamer V
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2008. Systemic signalling and changes in barley proteome after BYDV infection. 1st conference of the International Giessen Graduate School for the Life Sciences, Giessen
Steckbauer K, Friedt W, van Bel AJE
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2008. Systemic signalling in sieve tubes in response to infection by viruses and aphids. Seminarseries “News in cell biology and molecular biology”of the Research Center for Biosystems, Land Use and Nutrition Giessen
Steckbauer K
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2009. Barley Yellow Dwarf Virus detection and assessment of virus spread in susceptible and resistant barley plants. 5th Meeting of the German Phytomedical Society (Deutschen Phytomedizinische Gesellschaft) working group “viral diseases of plants” and the “Nederlandse Kring voor Plantenvirologie”
Spamer V, Obermeier C, Friedt W
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2009. Molecular interaction of Barley yellow dwarf virus and Hordeum vulgare. 2nd Conference of the International Giessen Graduate School for the Life Sciences, Giessen
Steckbauer K, Schulz B, Friedt W, van Bel AJE
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2009. Progress in Barley Yellow Dwarf Virus detection and assessment of virus spread in susceptible and resistant barley plants. 2nd Conference of the International Giessen Graduate School for the Life Sciences
Spamer V
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2009. Standardized infection and adjustment of 2DE for detection of BYDV effects on its host. 5th Meeting of the German Phytomedical Society (Deutschen Phytomedizinische Gesellschaft) working group “viral diseases of plants” and the “Nederlandse Kring voor Plantenvirologie”, Hamburg
Steckbauer K, Friedt W, van Bel AJE
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2010. Blattlausresistenz und Toleranz gegenüber Pflanzenviren. 1. Hessischer Biologentag, Landesverband VBIO Hessen, Wetzlar
Steckbauer, K
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2010. Proteinbiochemische, histologische und verhaltensbiologische Untersuchungen zur Aufklärung der Toleranz der Gerste (Hordeum vulgare L.) gegenüber BYDV-PAV. Ph D thesis, Justus Liebig University Giessen
Steckbauer K
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2010. Transcriptome analysis of the plant-aphid-virus interaction in Barley Yellow Dwarf Virus infected barley. Genomics-based breeding conference of the German Society for Plant Breeding (Gesellschaft für Pflanzenzüchtung e.V.) - Section “Genome Analysis“
Spamer V, Obermeier C, Friedt W
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2010. Vektor-Resistenz, effektiv gegen BYDV? 1. Hessischer Biologentag, Landesverband VBIO Hessen, Wetzlar
Steckbauer K, Schulz B, Friedt W, van Bel AJE
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2012. Transcriptome analysis of the plant-aphid-virus interaction in Barley Yellow Dwarf Virus infected barley. Annual general meeting of the German Society for Plant Breeding, Jahrestagung der deutschen Gesellschaft für Pflanzenzüchtung, GPZ, Gießen
Spamer V, Obermeier C, Friedt W
