|De La Torre, Carola|
|Redinbaugh, Margaret - Peg|
Submitted to: Phytopathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2012
Publication Date: 12/1/2012
Publication URL: http://handle.nal.usda.gov/10113/58204
Citation: De La Torre, C., Qu, F., Redinbaugh, M.G., Lewandowski, D.T. 2012. Biological and molecular characterization of a US isolate of Hosta virus X. Phytopathology. 102:1176-1181. Interpretive Summary: Virus diseases cause a loss of quality and vigor in ornamental plants such as hosta. An emerging virus, Hosta virus X (HVX), is becoming an important problem on hosta in the U.S. and worldwide. We examined different hosta cultivars for their responses to inoculation with an Ohio isolate of HVX, and found that four of the 21 cultivars tested developed no symptoms, and are candidate sources for resistance to HVX. We also sequenced the genome of the HVX isolate. While the sequence was similar to that of a previously sequenced isolate from Korea, there were key differences between the two. In vitro transcripts derived from the sequenced clone could be used to establish the virus disease in both hosta and Nicotiana benthamiana, indicating the sequence for the Ohio isolate was accurate. This 'infectious clone' of HVX will be valuable to researchers interested in virus resistance and infectivity in hosta, and could be used to develop tools to help understand the functions of hosta genes.
Technical Abstract: Hosta virus X (HVX) is rapidly becoming a serious pathogen of commercially important hosta plants worldwide. We report here a biological and molecular characterization of a US isolate of HVX, HVX-37. HVX-37 infectivity was tested in 21 hosta cultivars over three growth seasons, and three types of responses were defined based upon the ability of the virus to cause local and/or systemic infections. Four cultivars resistant to systemic HVX infection were identified. The full length sequence of the HVX-37 genome was determined, the first complete sequence of a U.S. HVX isolate. Comparison with the previously sequenced HVX-Korea (Kr) genome revealed a high level of sequence similarity, as well as some differences. Notably, a 105 nucleotide long, near perfect direct repeat in the Kr isolate is absent in HVX-37. The accuracy of the HVX-37 genome sequence was confirmed by infectivity of in vitro transcripts synthesized from a full-length HVX-37 cDNA on N. benthamiana and hosta plants.