Molecular characterization of Indian sugarcane streak mosaic virus isolate.

Sugarcane streak mosaic virus (SCSMV), a member of the genus Poacevirus, family Potyviridae, is an important viral pathogen affecting sugarcane cultivation in India. The complete nucleotide sequence of a SCSMV isolate from India (SCSMV-IND) was determined. The linear, assembled, single-stranded positive-sense RNA genome of SCSMV-IND was 9,786 nucleotides in length (excluding the poly (A) tail) and encoded a polyprotein of 3,131 amino acid residues. The genome of SCSMV-IND shared high degree of sequence identity with SCSMV-PAK (93 % at nucleotide and 97 % at amino acid), and shared only 81 % nucleotide and 94 % amino acid identities with all the four SCSMV isolates (SCSMV-JP1, -JP2, -ID, and -THA). Phylogenetic tree analysis of the complete genome sequences of SCSMV isolates revealed that they can be clustered into two groups. SCSMV-IND and -AP isolates showed 18 % (nucleotide) divergence within the highly conserved 3' partial genome, suggesting a high level of genetic diversity among the Indian SCSMV isolates.