|Gildow, Fred - PENN STATE UNIVERSITY|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 2006
Publication Date: January 10, 2007
Citation: Damsteegt, V.D., Scorza, R., Stone, A.L., Schneider, W.L., Webb, K.K., Demuth, M.A., Gildow, F.E. 2007. Prunus host range of plum pox virus (ppv) in the United States by aphid and graft inoculation. Plant Disease. 91:18-23 Interpretive Summary: Plum pox virus (PPV) produces a serious disease of stone fruits.Transmission of the virus occurs by aphid probing, by grafting, or by exchange of infected nursery stock. In response to an eradication control program instituted by APHIS and the Pennsylvania Department of Agriculture, we examined the potential of associated Prunus species to serve as reservoir hosts of the virus. More than 40 commercial, ornamental, and wild Prunus species were evaluated for their susceptibility to infection by PPV and their possible role as reservoir hosts through aphid transmission of the virus or grafting of infected buds into Prunus species seedlings. Several wild and ornamental species were highly susceptible to virus infection while others were only slightly susceptible. All 40 species grafted with infected buds produced at least one or more infected plants. Thirty-one of 33 species inoculated by aphid transmission exhibited some degree of susceptibility. Many species produced transient symptoms to infection and would be difficult to detect in routine surveys. There is a potential reservoir of wild and ornamental Prunus species available for maintaining sources of virus inoculum.
Technical Abstract: Plum pox (Sharka) is a serious virus disease of stone fruits caused by the Plum pox virus (PPV). Natural spread of the virus from tree to tree or orchard to orchard occurs by aphid transmission. Longer distance spread is mediated through grafting with infected budwood, and movement of infected nursery stock. Survival and spread of PPV can be mediated by infection of often asymptomatic Prunus hosts. To determine which species could function as potential hosts and virus reservoirs, we used aphid transmission (Myzus persicae Sulzer) and bud or chip grafting to evaluate the susceptibility of commercial, ornamental, and wild Prunus species to isolates of PPV found in Pennsylvania, USA. Following inoculation by aphids or grafting, test trees were observed for symptoms, analyzed by ELISA and PCR, and back-assayed to healthy peach (Prunus persica cvs Lovell or GF 305) through four cold-induced dormancy (CID) cycles over four years. Thirty-one of 33 Prunus species and cultivars tested were susceptible to infection by aphid transmission and all 40 species and varieties were susceptible by grafting. In a few species infection could only be detected through quantitative RT-PCR while many species displayed clear symptoms, were highly positive by ELISA and RT-PCR, and maintained virus titer following CIDs. Our results indicate that a wide range of native and ornamental Prunus species are susceptible to U.S. isolates of PPV-D.