Indian Journal of Virology

The disease/s caused by Cucumber mosaic virus (CMV), Chrysanthemum aspermy virus (CAV) and/or their strains causes significant losses to chrysanthemum cultivation in India and abroad. These viruses have become one of the limiting factors for commercial cultivation of chrysanthemums due to deteriorated quantity and quality of blooms. Chrysanthemums are being propagated by suckers or rooted cutting, as a result viruses present in the propagating materials are also being propagated from generation to generation.

Keeping in view the importance of chrysanthemums and the disease causal agent (CMV), attempts were made to develop a molecular based sensitive diagnostic method for reliable detection of CMV infection in chrysanthemum cultivars. RT-PCR using the total nucleic acid from infected leaf samples and the specific primers resulted the positive amplification of an expected size band of ∼650 bp in most of the samples. The identity of the PCR amplicons was checked by Southern hybridization using the α ³²P-labelled DNA probes prepared from the cloned coat protein gene of a well identified strain of CMV isolated from Amaranthus. Positive signal of hybridization with PCR product and CMV probe confirmed the identity of PCR amplicons as a fragment derived from the CMV genome in infected chrysanthemum samples.

Diagnosis of CMV and CAV infection in chrysanthemums had been performed earlier by serological detection tests such as double diffusion, immunosorbent electron microscopy (ISEM), enzyme linked immunosorbent assay (ELISA), western immuno blot assay. However, serological procedures some times are confusing to differentiate among the strains of Cucumovirus due to the cross reactivity between CMV, Tomato aspermy virus and Peanut stunt virus. Therefore, molecular diagnostic system has been recommended as more reliable and sensitive for certifying virus free propagating materials of chrysanthemum to be used for commercial cultivation.