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United States Department of Agriculture

Agricultural Research Service

Title: Current Research on Spiroplasma Citri in California

Authors
item Rangel, Benjamin
item Krueger, Robert
item Lee, Richard

Submitted to: International Organization of Citrus Virologists Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: November 7, 2004
Publication Date: May 1, 2007
Citation: Rangel, B., Krueger, R., Lee, R.F. 2007. Current research on spiroplasma citri in california. International Organization of Citrus Virologists Abstracts, Page 88.

Interpretive Summary: Stubborn disease, caused by Spiroplasma citri, has been a long-standing disease in most areas of California. Detection of the pathogen by conventional methods (culture) is made more difficult due to seasonal fluctuations in titer and uneven distribution of the pathogen in the tree. We now culture the samples in liquid media to increase the number of Spiroplasma, then extract the DNA and run a PCR assay, which ismore rapid and sensitive than the traditional culturing method. Seasonal fluctuations in titer are being studied and comparisons are being made between the San Joaquin Valley and Southern California areas. Apparent genetic variability in the Spiroplasma from different areas of California has been identified using AFLP. The PCR protocol utilized appears to detect all isolates studied.

Technical Abstract: Stubborn disease, caused by Spiroplasma citri, has been a long-standing disease in most areas of California. Because of uneven distribution in the plant and seasonal fluctuations in titer, detection of stubborn by biological indexing or the traditional culture method is not always reliable. To optimize the detection of stubborn, we now culture the samples in liquid media to increase the number of Spiroplasma, then extract the DNA and run a PCR assay. This method has proven to be more rapid and sensitive than the traditional culturing method. Presently seasonal fluctuations in titer are being studied and comparisons are being made between the San Joaquin Valley and Southern California areas. Apparent genetic variability in the Spiroplasma from different areas of California has been identified using AFLP. This research also has lead to the observation that stubborn disease is more widespread in California than previously believed, and that the economic losses are probably greater also.

Last Modified: 7/31/2014
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