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dc.contributor.authorFedkenheuer, Kevin E.en_US
dc.date.accessioned2018-01-06T07:00:10Z
dc.date.available2018-01-06T07:00:10Z
dc.date.issued2016-07-14en_US
dc.identifier.othervt_gsexam:8490en_US
dc.identifier.urihttp://hdl.handle.net/10919/81548
dc.description.abstractDisease outbreaks caused by oomycetes can be catastrophic. The first part of this dissertation describes development of a system to identify potential new and durable resistance (R) genes against P. sojae in soybean germplasm. We developed a system to screen soybean germplasm for genes that recognize core Phytophthora sojae RXLR effectors that are conserved within the pathogen species and essential for virulence. R genes that recognize these effectors will likely be effective and durable against diverse P. sojae isolates. We developed a system to deliver individual P. sojae effectors by Type III secretion into soybean using the bacterium Pseudomonas, and we screened 12 core effectors on a collection of 30 G. max lines that likely contain new resistance genes against P. sojae. We identified candidate R genes against 10 effectors. Genetic segregation ratios from crosses indicated that three of these genes have a simple inheritance pattern and would be amenable to breeding into elite cultivars. The second part of the dissertation involves use of a model plant-oomycete system to study the genetic basis of susceptibility to oomycete diseases. We compared host transcriptomes from a resistant and a susceptible infection of Arabidopsis thaliana by the downy mildew pathogen Hyaloperonospora arabidopsidis (Hpa). We identified five gene clusters with expression patterns specific to the susceptible interaction. Genes from each cluster were selected and null mutants were tested for altered susceptibility to virulent Hpa. Most A. thaliana null mutants showed enhanced disease susceptibility, suggesting their involvement in pattern-triggered immunity (PTI). A knockout mutant in the AtGcn5 gene was completely resistant to Hpa Emco5 suggesting that the gene/protein is necessary for Hpa to successfully colonize the plant. This study provided new molecular insights into plant-oomycete interaction and revealed a plant gene that could potentially be engineered to provide enhanced resistance to oomycete pathogens.en_US
dc.format.mediumETDen_US
dc.publisherVirginia Techen_US
dc.rightsThis Item is protected by copyright and/or related rights. Some uses of this Item may be deemed fair and permitted by law even without permission from the rights holder(s), or the rights holder(s) may have licensed the work for use under certain conditions. For other uses you need to obtain permission from the rights holder(s).en_US
dc.subjectGlycine maxen_US
dc.subjectSoybeanen_US
dc.subjectR genesen_US
dc.subjectEffector-directed breedingen_US
dc.subjectRXLR proteinsen_US
dc.subjectPhytophthora sojaeen_US
dc.titleMolecular Analysis of Oomycete Pathogens to Identify and Translate Novel Resistance Mechanisms to Cropsen_US
dc.typeDissertationen_US
dc.contributor.departmentPlant Pathology, Physiology, and Weed Scienceen_US
dc.description.degreePh. D.en_US
thesis.degree.namePh. D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen_US
thesis.degree.disciplinePlant Pathology, Physiology, and Weed Scienceen_US
dc.contributor.committeechairMcDowell, John M.en_US
dc.contributor.committeememberZhao, Bingyuen_US
dc.contributor.committeememberVinatzer, Boris A.en_US
dc.contributor.committeememberSaghai-Maroof, Mohammad A.en_US


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