RESUMEN
Grapevine leafroll-associated virus 1 [GLRaV-1] was detected in the grapevine plants collected from different cultivated areas in Egypt and tested using different serological and molecular tools. Double-antibody sandwich ELISA [DAS-ELISA] was successfully carried out using GLRaV-1 polyclonal antibodies to detect infected plants. PCR with primers designed at the heat shock protein 70 [HSP70] gene region, a fragment of 271 bp of GLRaV-1, was used. Molecular hybridization with non-radioactive probes was used to detect the presence of virus particles. The partial sequence of HSP70 fragment from the Egyptian isolate of GLRaV-1 was performed and showed high identity [95%] with the Australian isolate of GLRaV-1 sequence. The molecular methods used for viral diagnosis showed a higher sensitivity in the detection of GLRaV-1 compared to DAS-ELISA. These procedures may serve as an alternative method for GLRaV-1 detection, due to the weak sensitivity of ELISA test to differentiate between the different isolates