Development of an immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) using modified viral RNA release protocol for the detection of Grapevine leafroll-associated virus 3 (GLRaV-3)

摘要

Grapevine leafroll-associated virus 3(GLRaV-3) is the most destructive virus causing leaf roll disease in grapevine. ELISA has been widely used to screen the propagating materials for indexing of this virus at nursery stage. But the uneven distribution of GLRaV-3 in vines, its confinement to phloem tissues and impact of seasonal influences on its concentration limit the scope of ELISA. RT-PCR (reverse transcription-polymerase chain reaction), is a more sensitive technique, but not feasible for large scale screening purpose because of the tedious process of RNA isolation. Furthermore, location of virus particles and the presence of inhibitory compounds in the woody tissues of grapevine make RNA isolation problematic. Immunocapture-RT-PCR (IC-RT-PCR), more sensitive than ELISA and RT-PCR alone, is a technique where the virus can be detected without isolating the RNA. In this study, IC-RT-PCR was performed using different combinations of three virus extraction buffers and two virus nucleic acid releasing buffers along with one virus RNA releasing condition for the detection of GLRaV-3. The modified extraction and RNA release protocol developed in this study was validated for specific detection of the virus in the vines of five infected grapevine cultivars. This protocol can help in complementing the GLRaV-3 specific certification program of the country.