Submitted to: Plant Disease
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/1/2003
Publication Date: 4/1/2004
Citation: Tzanetakis, I.E., Halgren, A.B., Keller, K.E., Hokanson, S.C., Maas, J.L., McCarthy, P.L., Martin, R.R. 2004. Identification and detection of a crinivirus associated with strawberry pallidosis disease. Plant Disease. 88:383-390. Interpretive Summary: This paper characterizes a virus that is associated with strawberry pallidosis disease. The disease occurs in the US, Canada and Australia. This disease has been known for 45 years but a causal agent had not been identified. The disease is difficult to detect by grafting and thus it often occurs in nursery stocks and may well be worldwide in distribution. By itself it does very little damage and does not cause any obvious symptoms, but the synergistic interaction between pallidosis and other strawberry viruses has been suggested in the literature. We have developed a rapid, sensitive laboratory test for a virus that is associated with pallidosis disease. The virus that we characterize is a member of the Crinivirus genus in the Closteroviridae family of plant viruses. The RT-PCR test developed was able to detect the virus in 37 out of 38 samples that indexed positive for pallidosis. We propose the name Strawbery pallidosis associated virus for the virus that we identified. We have also developed antibodies that can be used to detect the virus in tissue blots using cross section of petioles. This test only works during the winter and spring months when the virus titer is at its highest and does not detect the virus during the summer months when titers are low.
Technical Abstract: The etiology of pallidosis, a disease of strawberry identified more than 45 years ago, remains unknown. In this report we identify a putative agent of the disease, a virus belonging to the Crinivirus genus of the Closteroviridae family. We have developed a sensitive RT-PCR test and developed antibodies to the virus using a recombinant virus major coat protein that can be used to detect the virus in petiole tissue blots. We report the full nucleotide sequence of the heat shock protein 70 homologue and the major coat protein of the virus. Phylogenetic analyses based on the coat protein and the heat shock protein 70 homologue genes show that the virus isolated from strawberry plants infected with pallidosis is most closely to the Cucurbit yellow stunt disorder virus and Sweet potato chlorotic stunt virus, members of the Crinivirus genus.