ISHS Acta Horticulturae 193: XIII International Symposium on Fruit Tree Virus Diseases
FURTHER EVIDENCE FOR VIROID ETIOLOGY OF APPLE SCAR SKIN AND DAPPLE APPLE DISEASES |
| Author: | H. Koganezawa |
| Abstract:
Two species of low molecular weight RNA have been associated with apple scar skin and dapple apple diseases. Both RNAs (ASSARNA 1 and ASSARNA 2) were purified from diseased apples. Polyacrylamide gel electrophoresis of the purified preparation under denaturing conditions showed that ASSARNA 1 existed in two forms, possibly linear and circular forms. Under the same electrophoretic conditions ASSARNA 2 migrated faster than the rapidly migrating form of ASSARNA 1. But under fully denaturing conditions (preheated to 100°C for one min.) ASSARNA 2 migrated more slowly than that of ASSARNA 1. Young seedlings were inoculated with ASSARNA 1 by the razor-slash method. Thirteen months after inoculation nucleic acid was extracted from the bark of inoculated seedlings and analysed by two cycles of polyacrylamide gel electrophoresis. ASSARNA 1 was detected in 8 of 14 inoculated seedlings. The results indicated that ASSARNA 1 was transmitted to apple seedlings and multiplied. All the properties of ASSARNA 1, so far examined, coincide with those of viroids. However, the pathogenicity of ASSARNA 1 and the role of ASSARNA 2 are still unknown. | |
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