Dissertation
DETERMINING THE TIME COURSE OF RASPBERRY BUSHY DWARF VIRUS MOVEMENT FROM POLLINATION TO SYSTEMIC INFECTION IN RED RASPBERRY
Doctor of Philosophy (PhD), Washington State University
01/2014
Handle:
https://hdl.handle.net/2376/111466
Abstract
The United States is the third largest producer of raspberries worldwide. Washington State is the leading producer of processed red raspberries, yielding 67 million pounds of fruit in 2013. `Meeker' is the commercially preferred cultivar in the Pacific Northwest and is susceptible to Raspberry bushy dwarf virus (RBDV, genus Idaeovirus). RBDV is the most important viral pathogen of Rubus crops. Resistant cultivars have been identified, with the resistance conferred by a single dominant gene, Bu. RBDV causes drupelet abortion leading to crumbly fruit that is not suitable for fresh or IQF markets, resulting in deep profit losses. As RBDV is pollen transmitted, control is limited to planting resistant cultivars. Breeding for RBDV resistance is a top priority for breeding programs, however, breeding the Bu gene into new crops using a conventional approach has been challenging. The first objective of this work is to investigate two previously identified genetic markers for their potential in marker assisted selection. Twenty crosses were made using selections with two RBDV-resistant parents crossed with the susceptible cultivar `Cascade Bounty.' Seedlings were grafted with RBDV-positive plant material and analyzed for RBDV by ELISA. Marker and ELISA results were compared and indicate that the genetic markers are not suitable for marker assisted selection. The second objective was to determine the time course of viral movement from pollination to systemic infection using Real-Time RT-PCR. Disease free and inoculum plants were placed in a screen house. At the onset of the bloom, bumblebees were introduced to transmit the virus. Experimental plants were destructively sampled at specific time points. The results revealed that RBDV achieves a systemic infection within 24 hours of bloom. In this work, two novel viral strains were discovered, one of which is able to replicate in the absence of capsid protein. The second strain is able to replicate in cultivars with the Bu gene, thus providing the first report of a resistance breaking strain of RBDV in North America. Further investigation is needed to identify genetic markers that are tightly associated with the Bu gene, and to characterize both novel viral strains identified in this work.
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Details
- Title
- DETERMINING THE TIME COURSE OF RASPBERRY BUSHY DWARF VIRUS MOVEMENT FROM POLLINATION TO SYSTEMIC INFECTION IN RED RASPBERRY
- Creators
- Kara Kristiana Lanning
- Contributors
- Patrick P Moore (Advisor)Robert R Martin (Committee Member)John K Fellman (Committee Member)Lisa W DeVetter (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Horticulture, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 88
- Identifiers
- 99900581532801842
- Language
- English
- Resource Type
- Dissertation