|Yokomi, Raymond - Ray|
|HAJERI, SUBHAS - Central California Tristeza Eradication Agency|
|BARNIER, JILL - Central California Tristeza Eradication Agency|
Submitted to: Phytopathology
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2015
Publication Date: 11/5/2015
Citation: Yokomi, R.K., Hajeri, S., Barnier, J. 2015. Survey of citrus tristeza virus populations in Central California that react with MCA13 monoclonal antibody. Phytopathology. 105:S4.154.
Technical Abstract: The Citrus Pest Detection Program (CPDP) of the Central California Tristeza Eradication Agency monitors Citrus tristeza virus (CTV) in Central California. MCA13 is a severe strain discriminating monoclonal antibody used to screen for potentially virulent CTV isolates. MCA13-reactive CTV isolates are rare in Central California and considered nonindigenous. Under the Effective Plan implemented in 2009, the CPDP surveys for only MCA13-reactive CTV isolates. For decades, participating pest control districts practiced mandatory CTV suppression. In these districts, from 2009 to 2013, 100% of citrus acreage (over 162,000) was subsampled using the hierarchical subsampling (HS) method. Of 985,797 samples, 25 were suspect positive for MCA13 CTV. Follow-up surveys confirmed 32 individual trees positive for MCA13 CTV, and these trees were removed. In an adjacent non-participating district that ceased mandatory removal in 1996,about 16% of over 100,000 citrus acres was subsampled under contract during the 2009 to 2013 period. Of 130,359 HS samples, 84 were suspect MCA13-positive. In two localized sites, followup surveys revealed 366 MCA13-positive trees. Some of these trees were not removed. These data suggest that non-removal of CTV-infected trees led to increased genetic diversity of CTV, and more potentially virulent CTV isolates. The results of RT-qPCR assays using genotype specific TaqMan-based probes support this observation.