The apple scar skin disease was first re- ported 60 years ago in China ( Manchuria) with the name “Manshu-sabika-byo” (19). Twenty years later, two apple. Cause These diseases are caused by Apple scar skin viroid. Many infected cultivars of apple or pear do not express symptoms of disease. Apple scar skin viroid(ASSVd), a pathogenic RNA viroid, infects apple and pear trees. To determine if ASSVd can also infect apricot, we performed reverse.

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This is especially important for apple viroids when considering the low-chilling cultivars of apple grown at low altitudes, where apple, herbaceous hosts and Tv are in close association.

Potato leafroll virus-assisted aphid transmission of potato spindle tuber viroid to potato leafroll virus-resistant potato. Separation and infectivity of circular and linear forms of Potato spindle tuber viroid.

The tips were placed on racks below a tube light in temperate-controlled chambers, and groups of 20 whiteflies fed on the solution.

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Varma A, Malathi VG. Following inoculation, the test plants were sprayed with an insecticide and kept in an insect-proof greenhouse pending the appearance of symptoms. These RNAs are likely to be taken up by the whitefly and possibly transmitted to new hosts.

Whiteflies can also affect hosts by producing a sticky secretion known as honeydew, which prevents leaves from functioning efficiently and acts as a substrate for fungi sooty molds. Results and Discussion A healthy Tv colony was maintained on seed-grown eggplant Solanum melongena. Spread of Tomato apical stunt viroid TASVd in greenhouse tomato crops is associated with seed transmission and bumble bee activity. In this study, ASSVd was found to be directly transmitted by a whitefly Tv that was otherwise free of whitefly-transmitted viruses.


However, there are no reports of direct insect vector transmission of viroids or the presence of viroid DNA DNA in insects. Some Japanese pear cultivars develop fruit dimpling symptoms when infected with the viroid Osaki et al.

Molecular characterization of Apple scar skin viroid from Himalayan wild cherry.

EPPO Global Database

The emergence and dissemination of whitefly-transmitted geminiviruses in Latin America. Plant Pathology ; Apple scar skin viroid ASSVdthe type member of the genus Apscaviroid within the family Pospiviroidaecauses scarring and dappling on apple fruits. In pear, in vitro therapy followed by apical meristem culture can be used to eliminate the viroid Postman and Hadidi, The DNA form of a retroviroid-like element is involved in recombination events with itself and with the plant genome. We also present evidence for the acquisition and transfer of naked RNA viroid transcripts by the insect vector under in vitro conditions and a potential role of CsPP2 in viroid transmission.

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Apple scar skin viroid

Some RNA species possess stem loop structures similar to tRNAs, zcar the existence of other unknown RNAs with such structures, which can confer increased stability, is probable. List of primers used in this study. In addition to the monomeric circular and monomeric linear bands, another band was observed in the whiteflies, which may correspond to replicative intermediates of viroid RNA.


Cold Spring Harbour Press. Because of the adaptation of the B.

A faint band corresponding to the ubiquitin ligase mRNA was also observed when using healthy cucumber phloem. Because some insects are known to possess endogenous reverse transcription activity, 18 total DNA of the whitefly was isolated and tested for a possible DNA form of the viroid using PCR. A GroEL homologue from endosymbiotic bacteria of the whitefly Bemisia tabaci is implicated in the circular transmission of Tomato yellow leaf curl virus.

The twenty whiteflies were then allowed access to groups of 5 healthy cucumber seedlings at the one-true-leaf stage. Most commercial pear cultivars show no symptoms when infected with ASSVd.

To screen for the presence of viroid in the viroidliferous whiteflies, we analyzed monomeric circular and linear RNAs. Although the amplified fragment was not affected by this treatment, it disappeared when the whitefly DNA was incubated with DNase and then examined using PCR not shown. Disclosure of Potential Conflicts of Interest No potential conflicts of interest were disclosed.

Introduction Whiteflies family Aleyrodidae are pests of herbaceous and woody plants in tropical countries and of greenhouse-grown plants in temperate climates.

Of the more than whitefly species described to date, only Bemisia and Trialeurodes whiteflies are known to be viral vectors, including B.