ISHS Acta Horticulturae 309: XV International Symposium on Fruit Tree Diseases
APPLE SCAR SKIN AND DAPPLE APPLE VIROIDS ARE SEED BORNE |
| Authors: | A. Hadidi, A.J. Hansen, C.L. Parish |
| Abstract:
The closely related viroids, apple scar skin (ASSV) and dapple apple (DAV), were found in seeds of apple fruit from infected trees by Northern blot hybridization analysis of nucleic acid extracts with a SP6-generated 32P labeled ASSV cRNA probe. Viroid amounts were greater in seed coats and subcoats than in seed cotyledons and embryos. ASSV and DAV were also detected in anthers, petals, receptacles, leaves, bark, and roots from infected trees. Viroid detection in these tissues was confirmed by reverse transcription-polymerase chain reaction (RT-PCR) followed by Southern blot hybridization analysis of the amplified products with the ASSV cRNA probe. This data suggests viroid infected trees constitute a potential source of the viroid for field spread. ASSV and DAV infected trees have been sporadically detected in commercial orchards in the United States and Canada. The infected trees were eliminated. These results clearly indicate ASSV and DAV are seed-borne implying that apple seedlings should no longer be assumed to be virus (viroid)-free. | |
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