Apple dimple fruit viroid: Fulfillment of Koch's postulates and symptom characteristics

Citation
F. Di Serio et al., Apple dimple fruit viroid: Fulfillment of Koch's postulates and symptom characteristics, PLANT DIS, 85(2), 2001, pp. 179-182
Citations number
19
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
PLANT DISEASE
ISSN journal
0191-2917 → ACNP
Volume
85
Issue
2
Year of publication
2001
Pages
179 - 182
Database
ISI
SICI code
0191-2917(200102)85:2<179:ADFVFO>2.0.ZU;2-4
Abstract
The previously reported properties of a small circular RNA isolated from pl ants of cultivar Starking Delicious with symptoms similar to those of the d apple apple disease induced by Apple scar skirt viroid (ASSVd), strongly su ggested that it is a distinct viroid species of genus Apscaviroid to which ASSVd also belongs. Nevertheless, the autonomous replication of this novel RNA, termed Apple dimple fruit viroid (ADFVd), and the nature of the sympto ms incited when inoculated free of other pathogens that might be present in the original source, were not determined. We addressed these questions by mechanically inoculating purified ADFVd into young apple seedlings (Golden) . Dot blot hybridization of leaf extracts collected ten months after inocul ation showed the presence of ADFVd in most of the inoculated seedlings, thu s proving the ability of this RNA to replicate independently. Material from these ADFVd-infected seedlings grafted onto the ASSVd indicator Starkrimso n incited the appearance on the fruit skin of discolored spots more or less depressed which were particularly frequent around the calyx cavity. Apple cultivars such as Gala, Pink Lady, and Braeburn reacted to ADFVd with simil ar symptoms, occasionally accompanied by scar skin in Braeburn, whereas ADF Vd replicated without eliciting any visible symptoms in other apple cultiva rs such as Golden, or in the pear indicator Fieud 37. No interference in sy mptom expression or viroid accumulation were observed in plants inoculated first with ASSVd and then with ADFVd.