Cloning and sequencing of coat protein gene of an Indian potato leaf roll virus (PLRV) isolate and its similarity with other members of Luteoviridae.

Abstract

An Indian strain of potato leaf roll virus (PLRV) was purified to generate complementary DNA corresponding to the coat protein (CP) gene. Virus cDNA was synthesized from purified viral RNA using oligo (dT)-anchor primer and virus specific primers. The viral sequence encoding the coat protein was specifically amplified by polymerase chain reaction (PCR), using specific primers bordering the CP gene. The unique amplified product thus obtained was A-T cloned into the pGEM-T Easy vector and the authenticity of the cloned gene verified by dot blot hybridization and sequence analysis. Run-way-transcripts of the cloned CP gene could detect PLRV in tissue imprints and tissue dilution. The nucleotide sequences and the deduced amino acid sequences were compared with the other PLRV isolates and found to be 97-99% identical at both the nucleotide and amino acid sequence level of other isolates. Multiple sequence alignment of deduced amino acid sequences revealed considerable homology to other luteoviruses. A nuclear localization signal located close to the N-terminus of the CP gene was predicted. This is the first report of PLRV coat protein sequence from an Indian strain.