Alignment of the sequence of TYLCV-THL component B with those of bipartite geminiviruses showed that the B component of TYLCV-THL and tomato golden mosaic virus (TGMV) (Hamilton et al., 1984) as well as squash leaf curl virus (SqLCV-e) (Lazarowitz and Lazdins, 1991) were about 55% nucleotide homology. In addition, the conserved hairpin loop structure of component B of the latter showed only two bases differences from that of TYLCV-THL as following ; GGCCATCCGTA-TAATATTACCGGATGGCC.C-A