S-24. PCR based detection and identification of Dasheen mosaic virus infecting edible aroids

Taro (Colocasia esculenta) and elephant foot yam (Amorphophallus paeoniifolius) are the major edible aroids cultivated in India. The mosaic disease caused by Dasheen mosaic virus (DsMV), genus Potyvirus family Potyviridae is the economically important disease affecting these crops world over. In India, 10 to 30 per cent mosaic disease incidence has been reported. The leaf malformation and chlorotic and white feathering along leaf veins are characteristic symptoms of dasheen mosaic disease on taro. On elephant foot yam also chlorotic patches and some times deformation of the leaves are common symptoms. The disease is primarily transmitted through the infected corms used as planting material. Different species of aphids are known to transmit the virus from infected plant to healthy plant under field conditions. In the present study, the total RNA from the infected plants were isolated and subjected to Reverse Transcription Polymerase Chain Reaction (RT-PCR) with Potyvirus group specific primers MJ1 and MJ2. An amplified DNA of 327 bp obtained was gel eluted, cloned in pGEM-T vector and sequenced. The sequence analysis and comparison using BLAST confirmed the similarity of the virus isolates under study to DsMV. The phylogenetic analysis revealed that virus from taro was closely related to the DsMV isolate SY1 reported from China and that of elephant foot yam was closely related to DESLK1 isolate of DsMV reported on yams. The RT-PCR method standardized using MJ1 and MJ2 primers was employed to detect DsMV in taro and elephant foot yam plants collected from farmers fields. The DsMV could be detected from symptomless taro and elephant foot yam. The RT-PCR based detection developed is useful for screening of aroid germplasm for DsMV infection and indexing of planting materials.