Psorosis and concave are citrus diseases of undemonstrated etiology that can be diagnosed by biological indexing. Its presumed causal agent is Citrus psorosis virus (CPsV) type species of the genus Ophiovirus. In this study improvement of a biological indexing assay for the detection of Citrus psorosis virus in citrus trees using rooted inoculated cuttings of indicator plants (Madam vinous, Dweettangor and Naveilina Orange) was achieved. Compared the results of detection of CPsV by traditional indexing using indicator seedlings and rooted inoculated cuttings of indictor plants were confirmed by (DAS-ELISA) and correlated with observation of symptoms thought to be specific, in field trees or in graft-inoculated indicator plants. The results showed that, improved technique of biological indexing using rooted inoculated cuttings of indicator plants was faster than the traditional method in addition sensitive and more consistent than ELISA test. RT-PCR technique was used to recognize Egyptian isolate of CPsV and would be adaptable for large scale application. GA3, ABA and IBA content in cuttings is remarkably higher than seedlings, while IAA content in leaves of cuttings was considerably lower than in the seedlings. The detection protocol described in this study could be used in citrus certification programs and to test trees in nurseries and commercial orchards for CPsV infection. |
