Development In The Control Of Potato Virus Diseases PDF Download

Potato (Solanum tuberosum L.) is one of the most important cash crops in Lebanon and worldwide. Potato is susceptible to many viruses; Potato virus Y (PVY), Potato virus X (PVX), Potato virus S (PVS), and potato leaf roll virus (PLRV) are among the most important. Yield losses may reach up to 70-80% with early infection by PVY or PLRV, especially when infected seed potato is used. Therefore, ELISA is used in certification schemes to screen for virus infection. This study aimed at comparing several detection methods that may serve as suitable alternatives to ELISA. Studies using leaf tissues, sprouts or tuber tissues showed that tissue print immunoassay (TPIA) and dot blot immunoassay (DBIA), which were not previously properly evaluated on potato, are equally effective to ELISA. TPIA was found to be an easy, less expensive, fast (4-5 hrs) and efficient technique for detection of the four major potato viruses, singly or in multiplex. Since each virus gives a different precipitation pattern, it was possible to detect the four viruses on a single membrane. The possibility to reuse the primary antibodies several times reduces considerably detection costs in DBIA and TPIA. Sprouts proved to be the best organ to be tested serologically while correction factors should be included when testing from either eyes or tuber stem end. Sensitivity and reliability in the diagnosis of potato viruses have been greatly improved after the introduction of nucleic acid based techniques. Primers designed for multiplex RT-PCR allowed detection of PVY, PVX, and PLRV simultaneously with an internal control. The digoxigenin labeled cDNA multiprobe allowed detection of the three viruses in one step; however, the detection efficiency was lower than single probes. Chemiluminescent detection provided a higher sensitivity than the colorimetric detection and within a shorter detection time. Among the four nucleic acid extraction methods tried, modified Dellaporta was the most efficient for hybridization assays. Tissue print hybridization using these probes was successful; it may be used for studies on viral movement. Reduction of labor, time, and costs was possible with the use multiplex RT-PCR or multiprobes.