Theses and Dissertations Collection

Potato mop-top virus (PMTV) and Tobacco rattle virus (TRV) are emerging potato pathogens in the United States. PMTV (Pomovirus: Virgaviridae) is a tripartite rod-shaped virus having single-stranded, positive-sense RNA genome encapsidated by a 19.7-kDa capsid protein. The virus is soil-transmitted by plasmodiophoromycete Spongospora subterranea. TRV is a bipartite rod-shaped, single-stranded, positive-sense RNA virus encapsidated by a 23.6-kDa capsid protein. TRV is unique in that RNA-1 can replicate and establish systemic infection in some hosts independent of RNA-2, which encodes for CP, resulting in a ‘capsidless’ virus infection and can present special problems for identification. TRV is also soil-transmitted and vectored by trichodorid nematodes. Both viruses can induce internal necrotic arcs in the flesh of affected tubers, diminishing their quality for processing and fresh market. Visual diagnosis is challenging since both viruses often do not induce symptoms in the foliage, and similar tuber symptoms can be caused by other potato viruses, such as Potato virus Y. Two sensitive and specific laboratory methods were developed for fast and reliable detection of PMTV and TRV in foliar and tuber samples from potato: a triple antibody sandwich enzyme-linked immunosorbent assay (TAS-ELISA), and an immunocapture (IC) reverse transcription (RT)-PCR assay. These TAS-ELISA and IC-RT-PCR methodologies were compared to commercially available detection kits from European diagnostic companies and found to be equal or superior in sensitivity and reliability.