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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A high incidence of ASSVd in commercial apple orchards has been observed, and this situation was thought to be related to the transmission of the viroid by razor blades in the field. To our surprise, the non-specific bp amplicon was neither vitoid whitefly origin nor a mutated shorter form of the viroid, as is viroi in the case of CaSVd-like RNA. The twenty whiteflies were then allowed access to groups of 5 healthy cucumber seedlings at the one-true-leaf stage.
Continuing to use www. As viroid-like secondary structures are found in some plant Biroid, and PP2 is known to bind and translocate several RNAs, the results have huge implications in transfer of these RNA species between plants visited by the whitefly. Go to distribution map Additionally, direct viroid transmission via any insect vector is thus far unknown. Some Japanese pear cultivars develop fruit dimpling symptoms when infected with the viroid Osaki et al.
Bean 21 and cucumber 22 RNA was used as negative control, the healthy whitefly 24 and viroidliferous whitefly 23 was also included in the blot, ASSVd dimeric transcript RNA inoculated cucumber 25 scag, bean 26tomato 27 and pea 28 were taken as positive control along with ASSVd monomeric insert containing plasmid 30, 31 and 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.
This circular DNA was apple to a 2.
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Introduction Whiteflies family Aleyrodidae are pests of herbaceous and woody plants in tropical countries and of greenhouse-grown plants in temperate climates. Dapple symptoms, which develop nearer to harvest, usually appear on the red-skinned cultivars e.
S3 and North-Western hybridization Fig. The causal agent is controlled through the use of healthy propagation materials indexing programmes and, if necessary, the removal of diseased trees.
Apple scar skin viroid (ASSVD0)[Overview]| EPPO Global Database
Knowledge Bank home Change location. Although symptoms of ASSVd are usually confined to the fruit, under certain conditions, some apple cultivars may develop leaf roll or leaf epinasty symptoms Ito and Yoshida, ; Koganezawa et al. Several workers have observed that the disease spread naturally to neighboring trees, 20,21 and ASSVd has been reported to be seed-borne but not seed-transmitted in apple.
Bar graph shows the percentage of infected cucumber plants which were inoculated through whiteflies. Plant Dis ; Separation and infectivity of circular and linear forms of Potato spindle tuber viroid. Varma A, Malathi VG.
Transmission to apple seedling of low molecular weight RNA from apple scar skin-diseased trees. 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.
Some RNA species possess stem loop structures similar to tRNAs, and the existence of other unknown RNAs with such structures, which can confer increased stability, is probable. However, there are no reports of direct insect vector transmission of viroids or the presence of viroid DNA DNA in insects. Groups of 20 whiteflies were transferred to 5 healthy cucumber plants. The healthy control plants tissue culture-grown cucumber and bean and healthy whiteflies did not react with the ASSVd ksin in the hybridization experiment and also yielded negative RT-PCR results.
EPPO Global Database
List of primers used in this study. Ann Phytopathological Society of Japan ; Almost all fruit on an infected tree of a susceptible cultivar will show symptoms and are unmarketable.
A serious threat to crop production. Sundararaj, Institute of Wood Science and Technology, Bengaluru, Karnataka, India for his help in identification of the whitefly species as Trialeurodes vaporariorum. Healthy plants were grown in an insect-proof growth chamber. Author information Article notes Copyright and License information Disclaimer.
In pear, in vitro therapy followed by apical meristem culture can be used to eliminate the viroid Postman and Hadidi, However, the role of plant host factors in determining the transmission efficiency cannot be overlooked. This experimental transfer also confirmed that the whitefly could take up naked RNA and transmit it, perhaps with the aid of certain whitefly proteins.
Scar skin and dapple apple viroids are seed-borne and persistent in infected apple trees.
Apple scar skin viroid
Ralls Janet, water-soaked blotches appear first, followed by scar tissue, and then cracking. Kyriakopoulou PE, Hadidi A.
Thomas Hohn, University of Basel, Switzerland for critically reading and editing the manuscript and Dr. 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.
Click here to view. Circular DNA was only amplified using samples from viroidliferous whiteflies Fig. Support Center Support Center. Results and Discussion A healthy Tv colony was maintained on seed-grown eggplant Solanum melongena.
Nucleic acid transfer between plants is a phenomenon which is likely to occur in many ways in nature. The viroid transfer efficiency was enhanced with the help of Cucumis sativus Phloem protein 2 CsPP2a plant protein known to translocate viroid RNAs. The same band was observed in non-viroidliferous whiteflies, but its intensity was comparatively quite low.
This is to ensure that we give you the best experience possible. All of these results led us to identify a role for PP2 in viroid transfer and its translocation as a complex from the plant to the whitefly. Replication of Avocado sunblotch viroid in the Yeast Saccharomyces cerevisiae.
RNA-mediated interference and reverse transcription control the persistence of RNA viruses in the insect model Drosophila. Open in a separate window. In sensitive cultivars, infection with the viroid causes significant reductions in fruit size and quality.