Organization and expression of the genomes of some Indian isolates of Rice tungro bacilliform virus
Organization and expression of the genomes of some Indian isolates of Rice tungro bacilliform virus
Three Indian isolates of Rice tungro bacilliform virus (RTBV) viz. West Bengal (WB), Andhra Pradesh (AP) and Tamil Nadu were cloned and studied for their homology and variability with each other and to the Philippine isolate of the same virus. The extent of homology between the two Indian isolates was found to be higher compared to the Philippine isolate. The coding regions (e.g. ORF II and ORF III) showed more homology than the non-coding regions. The genome size of the AP isolate was found a little lesser (7908bp) than the other South-east Asian isolates (~8002bp) of RTBV. This may be due to the deletions in the intergenic regions, resulting into an altered arrangement of the short ORF in the upstream untranslated region. In addition, a protoplast based transient expression assay revealed a functional promoter in RTBV comparable to the Maize ubiquitin promoter.