EVIDENCES SUPPORTING A VIROID ETIOLOGY FOR PEAR BLISTER CANKER DISEASE

A small circular RNA has been detected in nucleic acid preparations from pear tissue infected with several isolates of the pear blister canker (PBC) disease inducing typical bark symptoms in the pear indicator A 20, but not in parallel preparations from non-inoculated controls.
Purified preparations of this RNA displayed autonomous replication in pear and cucumber seedlings demonstrating in this way that it is a viroid, tentatively named pear blister canker viroid (PBCVd) because of its close association with the PBC disease, since two of the studied isolates were known to be affected only by this malady.
The size of PBCVd was estimated around 315 bases, and molecular hybridization analysis showed that it shared apparently sequence homologies with peach latent mosaic, hop stunt and apple scar skin viroids.
Other PBC isolates provoking bark disorders in the pear indicators ‘Williams’ and ‘Comice’ but not in A 20, did not contain detectable amounts of PBCVd, although Preliminary results indicated that after treating these plants at 28°C for two monts, low levels of an RNA similar in size to PBCVd could be observed.

XV International Symposium on Fruit Tree Diseases

C. Hernández, R. Flores, G. Llácer, J.C. Desvignes

Viroids, Pyrus communis, PAGE, molecular hybridization

https://doi.org/10.17660/ActaHortic.1992.309.46