Dissertation
Biological and molecular studies on potatovirus interactions using Potato virus S and Potato virus Y as model systems
Washington State University
Doctor of Philosophy (PhD), Washington State University
12/2013
DOI:
https://doi.org/10.7273/000005557
Abstract
Potato (Solanum tuberosum L.) is a staple food in the world. Potato virus Y (PVY; Potyvirus: Potyviridae) is an important virus that affects yield and quality of potatoes. PVY exists as biologically distinct strains: PVY-N induces systemic veinal necrosis in tobacco, PVY-O causes hypersensitive response (HR) in potato cultivars carrying the Ny gene and PVY-NTN produces necrotic rings on the tubers of sensitive potato cultivars. The vsiRNA profiles of three distinct PVY strains, ordinary (PVY-O), tobacco-veinal necrotic (PVY-N) and tuber-necrotic (PVY-NTN) strains were determined in potato cv. Russet Burbank. The frequency and distribution of vsiRNAs varied among different strains. PVY-NTN infected plants accumulated the highest population of PVY-vsiRNAs in comparison to plants infected with PVY-O and PVY-N. In PVY-infected plants, the 21 nt class was predominant whereas in healthy potato plants 24 nt class had the maximum population. VsiRNAs were derived from every nucleotide position of the PVY genome and certain hotspots were identified which produced relatively more vsiRNAs. Additionally, six novel microRNAs were found in PVY-infected plants. Potato virus S (PVS; Carlavirus: Betaflexiviridae) is another important potato virus distributed worldwide. The outcome of mixed infection of PVS and PVY was studied under controlled conditions in three potato cultivars, Defender, Desiree and Russet Burbank. Results showed that PVS has an antagonistic effect on PVY replication in mixed infection. The antagonistic effect was associated with less severe symptoms in dual infections as well as reduced PVY multiplication. Symptoms of PVS were not visible in Desiree and Russet Burbank plants except Defender which showed bronzing spots on the leaves. PVY symptoms included mosaic, mottling and leaf drop. It was found that the antagonistic effect of PVS on the replication of PVY is independent of host genetic background as the same pattern was found in all three potato cultivars. Potato cultivars such as Desiree carrying the Ny gene show HR to infection with the ordinary strain of PVY. In comparison to Russet Burbank, PVY levels in Desiree decreased with increasing number of days post-inoculation. The HR was found to be specific to PVY-O and was not elicited by infection by PVY-N or PVY-NTN.
Metrics
1 File views/ downloads
2 Record Views
Details
- Title
- Biological and molecular studies on potatovirus interactions using Potato virus S and Potato virus Y as model systems
- Creators
- Khalid Naveed
- Contributors
- Hanu R. Pappu (Chair)Amit Dhingra (Committee Member) - Washington State University, Horticulture, Department ofA KARASEV (Committee Member)PATRICIA OKUBARA (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Plant Pathology, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 174
- Identifiers
- 99901053937201842
- Language
- English
- Resource Type
- Dissertation