Background: Potato virus M (PVM) is found in potato cultivars worldwide including Egypt. Potato
tubers are a common source of the virus during host cultivations. The yield loss can range from 15% to
45% and heavy losses can occur upon mixed infection with PVM and PVS or PVX.
Objective: The current work aims to characterize the PVM, study cytopathic effect of PVM on
potato tissues, and detection of PVM in commercial potato seed tubers using RT-PCR.
Methods: The PVM was detected in symptomatic infected potato plants during growing seasons for
the cultivated commercial local tuber seeds using Double Antibody Sandwich-Enzyme Linked
Immuno-Sorbent Assay (DAS-ELISA). The PVM was mechanically isolated on potato cv. Diamant.
Host range was carried out by mechanical inoculation of PVM on a set of different plant species.
Electron Microscopy was used to examine the virus morphology. The cytopathic effect of the virus on
tissue ultrathin section was examined by transmission electron microscope (TEM). Finally, the PVM
isolate was detected using reverse transcription-polymerase chain reaction (RT-PCR) in the sprouts
after dormancy breaking for the harvested potato tubers.
Results: The obtained results demonstrated that, PVM isolate causes severe symptoms on potato plants
under the greenhouse conditions. The infected potato cv. Diamant gave positive DAS-ELISA result
using polyclonal antibodies against PVM. Moreover, the RT-PCR confirmed PVM in tuber sprouts
using coat protein gene specific primers with an expected amplicon of 520 bp. Electron Microscopy
examination revealed that, the viral particles were slightly flexuous rod shape with about 680 x 13 nm
in size. Ultrastructure analysis showed different degrees of chloroplast degradation in PVM-infected
potato leaf tissues.
Conclusion: Occurrence of PVM was detected and confirmed in commercial potato seed tubers in
Egypt using the RT-PCR technique. |
