Thesis
Genetic diversity of Tomato spotted wilt virus
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/102321
Abstract
Tomato spotted wilt virus (TSWV; family Bunyaviridae, genus Tospovirus) continues to cause economically important diseases in a wide range of agricultural and horticultural crops worldwide. The global distribution, broad host range and transmission by several vector thrips species (Thysanoptera: Thripidae) contribute to TSWV’s recognition as one of the top ten economically important plant viruses. Similar to other RNA viruses, TSWV is known to maintain heterogeneous and divergent populations with individual isolates that exhibit distinct epidemiological characteristics. The resurgence of isolates capable of overcoming host plant resistance, in addition to the propensity for genome mutation, recombination and reassortment, make it necessary to continuously monitor genomic diversity of the virus for applications in crop improvement. Despite the economic significance of TSWV to agriculture in the United States (US), very few studies have examined the nation-wide genetic diversity of the virus. Fifty-four TSWV isolates were collected from different plant species and geographic locations within the US between 2012 and 2015. Protocols were optimized to amplify, clone and sequence full-length M- and S-RNA genome segments of TSWV. The strategy presented is straightforward, scalable and offers several advantages over the previously commonplace and overlapping amplicon-based approach. A global phylogenetic analysis of the M- and S-RNA sequences obtained revealed greater genetic diversity of TSWV than previously shown within the US. At least six isolates showed clear phylogenetic incongruence among M- and S-RNA phylograms, suggesting genome segment reassortment. This study represents the first large-scale examination of TSWV isolates at the genomic segment level and provides further knowledge of TSWV genetic variation across the US. This study also lays the foundation to further elucidate genome-wide genetic diversity and molecular epidemiology of TSWV in single and co-infections to provide better understanding of disease epidemics and enhanced durable resistance against the virus.
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Details
- Title
- Genetic diversity of Tomato spotted wilt virus
- Creators
- Spencer Harrison Marshall
- Contributors
- R. A. Naidu (Chair)Dennis A Johnson (Committee Member) - Washington State University, Plant Pathology, Department ofScott Adkins (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Plant Pathology, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 54
- Identifiers
- 99900525046601842
- Language
- English
- Resource Type
- Thesis