Author
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Waterworth, Howard |
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Mock, Raymond |
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Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 8/13/1999 Publication Date: N/A Citation: N/A Interpretive Summary: Several diseases of fruit crops are caused by microscopic organisms known as phytoplasmas some of which do not occur in the United States. Therefore when fruit trees are imported they must be held in quarantine and tested for these disease agents in the laboratory. In the past this was done by grafting buds from imported trees onto domestic varieties that are known to display diseases if these agents are present. It took as long as 3 years for the symptoms to develop. In this report a new procedure, polymerase chain reaction (P C R), is shown to detect the nucleic acids of phytoplasmas in less than one day to include what are presumably dead disease agents. This procedure will be useful for persons/agencies who certify pathogen fruit germplasm in many countries. It will also be useful to State regulatory offices and nursery companies who sell certified virus tested cultivars. Technical Abstract: The use of nested PCR assays were evaluated for use on a routine basis in the quarantine program to detect phytoplasmas in dormant fruit tree scionwood collected during the winter season. Phytoplasmas were detected in all known infected sources; the pathogens associated with peach yellow leaf roll, Western X disease, apricot chlorotic leaf roll, plum leptonecrosis, and apple proliferation diseases. Use of nested PCR vs single primer pair, resulted in easier-to-interpret results of electrophoresed PCR products. This procedure has replaced the 3 year graft tests onto sensitive indicators to detect this group of pathogens. |
