First Report of Citrus Bent Leaf Viroid and Citrus Dwarfing Viroid in Argentina

Samples collected from citrus trees with viroid-like symptoms in citrus orchards in Tucumán, Salta, and Jujuy provinces(northwestern Argentina) were initially indexed on citron (Citrus medica) and then analysed by s-PAGE. These samples werefound to be infected with different viroid species, among them, CEVd and HSVd have been already identified. In order todetermine the presence of other viroids, we performed a RT-PCR assay using specific primers for CBLVd, CDVd, Citrus barkcracking viroid (CBCVd) and Citrus viroid V (CVd-V).Forty-two samples including 15 lemons, 15 oranges, 8 grapefruits, 2 citrumelos and 2 Cleopatra mandarins were analysed.On the basis of amplification of the appropriately sized DNA, CDVd was detected in thirty-eight samples and CBLVd in allgrapefruit samples. CBCVd and CVd-V were not found in any samples to date. Analysis of the amplicon sequences revealed96% and 97% identity with CBLVd GenBank reference sequences, and 96% to 98% with CDVd GenBank referencesequences.This is the first report of CBLVd and CDVd in citrus trees in Argentina. The results indicate that CDVd is widely spreadthroughout the surveyed areas and it is even more prevalent than CEVd and HSVd. Moreover, a considerably high percentageof citrus species are affected by mixed viroid infection. It would be important to take it into consideration when developingcitrus disease management strategies