Comparative Analysis of RT-PCR and IC-RT-PCR for Detection of Tobacco streak virus and Its Characterization in Sunflower (Helianthus annuus L.)

Tobacco streak virus (TSV) is the most economically important virus infecting sunflower (Helianthus annuus L.) collected from the field was detected by Immunocapture (IC) RT-PCR, with serologically positive samples using direct antigen coating enzyme linked immunosorbant assay (DAC-ELISA). The virus infected samples collected from the field were produced characteristic local necrotic lesions onprimary inoculated leaves, followed by systemic infection by mechanical inoculation on cowpea cv C152. The coat protein gene was amplified with a size of 929 bp including UTR region as part of RNA3 region of TSV. The nucleotide and deduced amino acid analysis of CP gene of TSV revealed that, CP gene of TSV-CPKAR isolate shared a high degree of sequence homology with other TSV isolates available in Genbank database. Phylogenetic tree constructed based on nucleotide and amino acid sequence showed a close clustering of TSV-CPKAR isolate with other TSV isolates from India. The IC-RT-PCR was found to be more sensitive than the RT-PCR by compared using serial dilutions of sap and RNA prepared from TSV infected sunflower samples collected from field.