Incidence and Characterization of Mild and Severe Isolates of Citrus Tristeza Virus from Colombia

Abstract

Surveys of the major citrus-producing regions, nurseries and germplasm collections in Colombia indicated widespread presence of severe isolates of citrus tristeza virus (CTV). Nearly 90% of the samples tested were infected with CTV, and over 60% reacted positively with the MCA13 monoclonal antibody, which reacts to most severe strains of CTV. The capsid protein (CP) sequences of MCA13 reactive isolates were similar to known stem pitting strains, and the isolates did cause stem pitting on grapefruit and lime in biocharacterization tests. Thus, these isolates pose a threat to citrus production in Colombia and this region. However, the isolates from Mompox did not react with MCA13, their CP sequences were similar to known mild isolates, and they caused no symptoms on grapefruit or lime. Further research on Mompox CTV isolates may provide information useful for controlling CTV in Colombia and other countries by cross-protection.