MOLECULAR CHARACTERIZATION OF THE GARLIC VIRUS-X GENOME

The complete nucleotide sequence of the cDNA genome for garlic virus X (GVX), one of the major viruses infecting garlic plants, was determin ed. GVX is a single-stranded positive-sense RNA virus consisting of 81 06 nucleotides excluding the 3'-end poly(A) tail and contains six open reading frames (ORFs) which encode putative proteins of 174 kDa (ORF1 ), 26 kDa (ORF2), 12 kDa (ORF3), 32 kDa (ORF4), 26 kDa (ORF5) and 15 k Da (ORF6). The putative viral proteins show similarity to those of car laviruses and potexviruses but show the highest homology to shallot vi rus X (ShVX). Even though the GVX genome contains most of the structur al elements common to carlaviruses and potexviruses, it is distinguish ed from them by the presence of an ORF4 which encodes an unusual prote in. These results suggest that GVX may belong to an unassigned group o f ShVX and GarV-type viruses rather than to the carlaviruses or potexv iruses.