ISHS Acta Horticulturae 472: XVII International Symposium Virus and Virus-Like Diseases of Temperate Fruit Crops
RELATIONSHIP OF CHERRY VIRUS A TO LITTLE CHERRY DISEASE IN BRITISH COLUMBIA |
| Authors: | K.C. Eastwell, M.G. Bernardy |
| Abstract:
Mealybugs were used to transmit little cherry disease (LCD) from a symptomatic orchard tree in British Columbia to a virus-tested 'Lambert' sweet cherry. The LCD isolate (LC5) was transferred to a stock tree of 'Lambert' by T-budding; a cDNA library was prepared from the double-stranded RNA isolated from this LCD-infected tree. From this library, clones were isolated representing the closterovirus associated with LCD in British Columbia. However, several clones obtained from the same library were representative of a second virus, cherry virus A (CVA). CVA is a capillovirus that has recently been identified and characterized in Germany. Based on the sequence of a clone from the RNA replicase region of the British Columbia CVA, a RT-PCR test was developed. This test is used to obtain information about the distribution of CVA in our virus collection, and the relationship of CVA to the occurrence of LCD. Several 'Lambert' trees were identified that reacted positively in the RT-PCR test for CVA, but exhibited no acute symptoms of disease. No data are available on the impact of CVA on fruit yield from these sweet cherry trees. Trees of the cherry cultivar 'Canindexl' were budded with orchard samples to test for LCD; these trees were subsequently tested for CVA by RT-PCR. Some of the 'Canindexl' trees inoculated with orchard samples from the LCD survey contained CVA, but there was no correlation between the expression of LCD symptoms and the presence of CVA. Screening of field samples continues. The sequence of the RNA replicase clone derived from the British Columbia isolate of CVA was compared to that of the German isolate of CVA. Furthermore, cycle sequencing was used to examine another six CVA isolates found in British Columbia. The sequences of the British Columbian isolates are very similar to those of the German isolate. | |
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