Submitted to: International Organization of Citrus Virologists Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 11/22/2005
Publication Date: 1/10/2007
Citation: Ramos, C., Castillo, J.C., Fernandez, O., Rangel, B., Keremane, M.L., Lee, R.F. 2007. Molecular Characterization of Citrus tristeza virus Isolates from Panama. International Organization of Citrus Virologists Proceedings, 16th Conference, Pgs. 159-164. Interpretive Summary: Citrus is an increasingly important crop in Panama, and Citrus tristeza virus (CTV) poses a risk to continued economic production. Twelve isolates of CTV were collected and characterized at the molecular level. The isolates were genotyped and the coat protein genes sequenced. Three isolates were identified as potential mild strains and are undergoing further evaluation for use for cross protection against very severe strains of CTV from Panama.
Technical Abstract: Twelve isolates of Citrus tristeza virus (CTV) were collected from the main citrus growing regions in Panama and characterized at the molecular level. The CTV coat protein gene (CPG) was amplified by RT-PCR, and the amplified PCR products were cloned and sequenced. The sequences analyses showed the relatedness among the Panama isolates and with the CTV isolates available in Genebank. The CTV isolates were further examined using the multiple molecular markers (MMM) method to determine genotype. Four of the isolates were T30 genotype (CTVP-02, CTVP-14, CTVP-19, and CTVP-26). The rest of the isolates were identified as a mixture of two genotypes with isolate CTVP-18 appears to be a complex mixture of several genotypes and this was the only isolate tested which had a product amplified with the T36-Pol specific primers. Isolate CTVP-22 was amplified only with the universal marker, the T36-CPG primer pair, and had no products amplified with any of the other MMM primer pairs. Based on the CPG sequence, three of the 12 isolates are reactive with the monoclonal antibody, MCA-13, used in Florida to identify CTV isolates which cause decline on sour orange rootstock. These results are being used to identify potential mild strains of CTV for further evaluations for mild strain cross protection.