P-19. Detection of Dasheen mosaic virus causing mosaic in elephant foot yam through RT-PCR
Abstract
Among tropical tuber crops, elephant foot yam (Amorphophallus paeoniifolius) is getting popular in India due to its high economic returns besides its uses in various delicious cuisines and medicinal applications. Mosaic disease induced by the virus/es is an important problem since the crop is vegetatively propagated and the disease easily spreads through infected planting material. In India, association of a Potyvirus, aCarlavirusandDasheen Mosaic Virus(DaMV) with elephant foot yam mosaic has been reported based on ISEM and serological studies. In the present study, attempt was made to detect and identify the virus at molecular level. The samples obtained from different regions showed viral symptoms such as mosaic mottling, filiformy, chlorosis, leaf curling and puckering. Host range studies of the virus on different indicator plants through sap inoculation, aphid transmission and grafting, resulted in the appearance of symptoms only on one plant each of Nicotiana tabacum, N. debneyii and Philodendron sp.RT-PCR amplification of the viral genome using Potyvirus specific degenerate primers MJ1 and MJ2 resulted in the amplification of a 291bp partial coat protein gene. The amplified product was then cloned in pGEM-T Easy vector and then transformed in Escherichia coli DH5á. Sequencing and phylogenetic analysis of the amplified product confirmed similarity of the virus under study with Dasheen mosaic virus (>90% at both nucleotide and amino acid level). The phylogenetic tree constructed with TREECON software using 100 bootstrap values indicated 90% similarity with the DaMV isolate DeSLK2 (NCBI Accession No.AJ305434). Based on the sequence information of DaMV available in gene bank database, DaMV specific and degenerate primers have been designed using primer design software. RT-PCR of the viral genome using degenerate primers resulted in the amplification of complete coat protein gene of desired size. This confirms the association of DaMV with mosaic disease of elephant foot yam, in India.
