RT-PCR-RFLP analysis for evaluating cross protection by an attenuated isolate of Cucumber mosaic virus

CM95 is a good attenuated isolate of Cucumber mosaic virus (CMV) for practical use in cross protection. To assess the protective ability of CM95 in the field, reverse transcription-polymerase chain reaction-restriction fragment length polymorphism (RT-PCR-RFLP) was developed to differentiate CM95 from severe CMV isolates in a short time. In cross-protection tests, protection by CM95 as evaluated by RT-PCR-RFLP on challenge-inoculated leaves 14 days after inoculation agreed with the results obtained in a concomitant experiment to assess symptom appearance on upper leaves 1 month after inoculation. It demonstrated that the RT-PCR-RFLP technique is a reliable method for evaluating the cross-protective ability of CM95 in a short time, in contrast to the month needed for symptoms to appear on upper leaves during the standard evaluation. [PUBLICATION ABSTRACT]