ISHS Acta Horticulturae 550: XVIII International Symposium on Virus and Virus-like Diseases of Temperate Fruit Crops - Top Fruit Diseases
PEACH ROSETTE, LITTLE PEACH, AND RED SUTURE ARE DISEASES INDUCED BY A PHYTOPLASMA CLOSELY RELATED TO WESTERN X-DISEASE |
| Authors: | S.W. Scott, M.T. Zimmerman |
| Keywords: | Phytoplasma, Little peach, Red suture, Peach rosette, Western X-disease |
| DOI: | 10.17660/ActaHortic.2001.550.51 |
| Abstract:
Samples of peach rosette, little peach, and red suture diseases were collected in South Carolina, Georgia, and West Virginia and grafted to peach seedlings. A single isolate of each disease was transmitted to periwinkle (Catharanthus roseus) using dodder (Cuscuta pentagona) grown from seed. DNA was extracted from both the original samples and periwinkle and the 16S rDNA of the phytoplasma was amplified by nested PCR using the universal primer pairs of Gundersen and Lee (Phytopath. medit. 35, 144-151, 1996). The 1247 bp product amplified from each disease was cloned and sequenced. Paired comparisons of the sequences showed >99% among all sequences irrespective of the disease with which they were associated. Comparisons of the 3 sequences with the corresponding segment of the published sequence for the 16S rDNA of western X-disease (GenBank accession L04682) also showed >99% similarity. Grafting peach rosette and little peach to peach seedlings resulted in transmission of both the phytoplasma and the disease. However, although grafting of red suture transmitted the phytoplasma (as detected by PCR), the disease was not observed in fruiting trees. The distribution of peach rosette within orchards suggests immigration into the orchard from adjacent native vegetation. Attempts to locate alternate hosts of the phytoplasma using PCR detection have been largely unsuccessful. However, the phytoplasma has been detected in wild plum (Prunus angustifolia) which survives from season to season and displays yellowing and reduced growth as compared to wild plum in which the phytoplasma was not detected. The sequences of the 16S rDNA of peach rosette, little peach, and red suture have been deposited in GenBank as accessions AF236121, AF236122, and AF236123, respectively. | |
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