RNA interference mediated virus resistance in transgenic wheat

dc.contributor.authorRupp, Jessica Lynn Shoup
dc.date.accessioned2015-08-14T18:43:55Z
dc.date.available2015-08-14T18:43:55Z
dc.date.graduationmonthAugusten_US
dc.date.issued2015-08-01en_US
dc.date.published2015en_US
dc.description.abstractWheat streak mosaic virus (WSMV) and Triticum mosaic virus (TriMV) are two viruses affecting wheat in the Great Plains region of the United States. Genetic resistance is severely limited, requiring management methods focusing on the deployment of resistant varieties and various cultural practices. Evaluation of resistance is complicated by the lack of a standard rating scale. The objective of this work was to develop new avenues to mitigate these challenges. A standardized virus symptom rating scale was developed using historical Kansas rating scales, and validated using multiple wheat populations. Two independent RNA interference (RNAi) expression vectors targeting portions of viral coat protein (CP) of WSMV and TriMV were previously transformed into wheat. T₂ plants and beyond were evaluated using PCR, reverse transcription-PCR and bioassays in which plants were challenged with their respective virus. These lines were evaluated for resistance through the T₆ generation. Crosses were made with the susceptible winter wheat cultivars, ‘Overley’ and ‘Karl 92.’ Real-time PCR results show viral titer was up to 20-fold lower in the T₆ transgenic lines, the F₁, and the BC₁F₁ compared to control plants. This provides evidence that this RNAi silencing method is stable in wheat over multiple generations. WSMV and TriMV use host eukaryotic initiation factors (eIF) in order to facilitate replication of their genomes. Previously created RNAi expression vectors were derived from the sequences of the wheat genes eIF(iso)4E-2 and eIF4G. Evaluation of these lines began in the T₁ generation. Resistance has been demonstrated in three lines of eIF(iso)4E-2 and four lines of eIF4G, derived by single seed descent. T₆ progeny co-infected with WSMV and TriMV continue to be resistant. Crosses have been performed with the winter wheat ‘Karl 92’ and three Kansas elite lines, KS030887K-6, KS09H19-2-3, and KS10HW78-1-1. RNAi construct effectiveness was evaluated using real-time PCR. Results show up to 18-fold reduction in viral titer in the transgenic lines, the F₁, and the BC₁F₁ in comparison to control plants. This research provides the first evidence that a single host transgene can provide resistance to multiple viruses and has great potential benefits to both breeders and producers.en_US
dc.description.advisorJohn P. Fellersen_US
dc.description.advisorHarold N. Tricken_US
dc.description.degreeDoctor of Philosophyen_US
dc.description.departmentPlant Pathologyen_US
dc.description.levelDoctoralen_US
dc.description.sponsorshipKansas Wheat Commission USDAen_US
dc.identifier.urihttp://hdl.handle.net/2097/20387
dc.language.isoen_USen_US
dc.publisherKansas State Universityen
dc.subjectTransgenic wheaten_US
dc.subjectVirus resistanceen_US
dc.subjectHost gene silencingen_US
dc.subjectPathogen derived resistanceen_US
dc.subjectRNA Interferenceen_US
dc.subjectVirus rating scaleen_US
dc.subject.umiPlant Pathology (0480)en_US
dc.titleRNA interference mediated virus resistance in transgenic wheaten_US
dc.typeDissertationen_US

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