SEQUENCE-ANALYSIS OF RICE-HOJA-BLANCA-VIRUS RNA-3

RNA 3 of rice hoja blanca tenuivirus (RHBV) has 2299 nucleotides and r esembles RNA 3 of other tenuiviruses such as maize stripe (MStV) and r ice stripe (RStV) viruses in potentially coding with an ambisense stra tegy for two proteins. Both the viral-sense protein of 23K and the com plementary-sense protein of 35K have about 46% amino acid identity wit h the analogous proteins encoded by RNA 3 of MStV and RStV. As the pro teins of MStV and RStV have about 65% identity between themselves, RHB V cannot be a South and Central American strain of the Asian RStV. The intergenic region resembles those of other tenuiviruses, being rich i n A and U residues, but its predicted folding pattern is unlike those of other tenuiviruses. Instead, the predicted folding of the intergeni c region was indistinguishable from that of the coding regions and the re was no evidence for a distinct hairpin-loop structure. The signific ance to the evolution of tenuiviruses of the similarities that the two proteins have with their analogues in other tenuiviruses is discussed .