|Ochwo-Ssemakula, M -|
|Aritua, V -|
|Sengooba, T -|
|Hakiza, J -|
|Adipala, E -|
|Ekwamu, Adipala -|
|Winter, S -|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 15, 2011
Publication Date: April 15, 2012
Repository URL: http://handle.nal.usda.gov/10113/56266
Citation: Ochwo-Ssemakula, M., Aritua, V., Sengooba, T., Hakiza, J.J., Adipala, E., Ekwamu, A., Redinbaugh, M.G., Winter, S. 2012. Characterization and distribution of a Potyvirus associated with passion fruit woodiness disease in Uganda. Plant Disease. 96(5):659-665. Interpretive Summary: Passion fruit is largely grown by small farmers in Uganda, and is a major cash crop for these producers. A disease called passion fruit woodiness has been a problem for Ugandan producers. About ten years ago, the Ugandan National Agricultural Research Organization determined that nearly all passion fruit fields in Uganda had plants with suspected virus diseases, and estimated that disease losses could be up to 50%. In this study, we investigated the frequency and causes of the suspected virus disease of passion fruit in Uganda. Viral disease symptoms were prevalent in all geographic areas producing passion fruit, with an average of 27% of plants showing virus symptoms. Analysis of these symptomatic plants indicated that a family of viruses called the Potyviridae was present. Further study indicated the disease-causing virus is a new strain of Passiflora chlorosis virus (PaChV). This research will form the basis for developing robust and economical diagnostics for this new virus species.
Technical Abstract: This paper describes the incidence and etiology of viral infection on passion fruit in Uganda. Viral disease symptoms, including those characteristic of Passion fruit woodiness disease (PWD), were observed in producing areas with an overall mean infection level of 27%. Electron microscopic observations of infected tissues revealed flexuous filaments (modal length 780 nm). Enzyme linked immunosorbent assay of these particles showed serological relationship to Cowpea aphid-borne mosaic virus (CABMV) and Passion fruit ringspot virus. In host range studies only species in the families Solanaceae and Chenopodiaceae were infected but not Vigna unguiculata or Phaseolus vulgaris. Coat protein gene sequences of four isolates displayed typical features of members of the genus Potyvirus but distinct from the three potyviruses reported to cause PWD; CABMV, East Asian Passiflora virus and Passion fruit woodiness virus. Phylogenetic analyses revealed the proposed new species Passiflora chlorosis virus (PaChV) as the most similar virus (80% amino acid (aa) homology) while isolates from Uganda were closely related (88 to 100% aa similarity). In accordance with current criteria set by the International Committee for Taxonomy of Viruses for species demarcation within the family Potyviridae, we conclude that a strain of the Passiflora chlorosis virus causes PWD in Uganda.