Molecular Diagnosis of Spiroplasma citri in Citrus Cultivars, Using PCR-based Assay in Compare with DAS-ELISA: Brief report

Spiroplasma citri, the causal agent of stubborn disease has become one of the destructive pathogen of citrus industry in Iran. One of the most important strategies for control of stubborn disease is using S. citri-free mother trees, propagative material and citrus nurseries and disease avoidance in new orchards. In this way, the efficiency of the standardized ELISA with poly clonal antibody and PCR protocol with three different primer pairs was assessed. The results revealed that ELISA was not able to detect low titre of infection (in symptomless samples) so using ELISA techniques in certification system was not recommended and has significant problem such as false negative reaction. PCR method and specially P89f/r primers in compare with two other primers P58-1f/5r and P58-6f/4r was able to detect low titre of north and south strains of pathogen in moderate seasons. Out of a total 350 samples screened for presence of S. citri by the PCR method only 4/6 % showing positive results in symptomless samples.