Further support of genetic conservation in Indian isolates of Rice tungro bacilliform virus by sequence analysis of an isolate from North-Western India

The genomic sequence of an isolate of Rice tungro bacilliform virus (RTBV), collected from the state of Punjab (Pb), a non-endemic tungro region from North-Western India was determined. In silico comparison of the 7931-bp sequence with isolates from Southeast Asia and the three previously characterized Indian isolates, revealed not only similar genome size to other Indian isolates but also high degree of homology both at nucleotide (> 93 %) and amino acid (> 96 %) levels among them. On the other hand, like the other Indian isolates, RTBV-Pb showed much lower nucleotide (< 87 %) and amino acid (< 90 % in most of the open reading frames) identities with the Southeast Asian isolates owing to several nucleotide substitutions and indels. In-depth annotation comparisons reinforce the hypothesis that Indian isolates of RTBV have diverged sufficiently from the Southeast Asian ones to form a separate group.