MOLECULAR DETECTION OF VIRUSES IN PLANTING MATERIAL OF TAMARILLO IN COLOMBIA

摘要

Tamarillo virus disease is caused in Colombia by a complex of at least seven viruses, including some members of the genera Potyvirus, Cucumovirus, Polerovirus and Tobamovirus. The propagation of this fruit crop is made by sexual seed; therefore, it is important to warranty its health, especially because PVY and PLRV can be transmitted through this way. In this research, the phylogenetic analysis of PVY and PLRV isolates was carried out. They were detected in sexual seeds and plant seedlings of tamarillo obtained from different Colombian provinces. Additionally, the molecular hybridization techniques with probes for the capsid gene were developed as diagnostic tools for the genus Potyvirus and the species PLRV. The phylogenetic analysis of PVY sequences grouped the isolates obtained from seedlings with those previously reported from leaf tissue of adult plants, but not with any of the clades representing the known PVY strains. In the case of PLRV, the strains sequenced were associated to isolates of potato crops from different countries. Tests of dot-blot showed similar levels of detection to conventional ELISA, but not to the tissue-printing method, which detected a 15% less than positive samples detected by ELISA. This study shows the urgent need to develop seed certification programs for this crop in Latin America.