Plasmid cDNA clones, with transcription in planta controlled by the cauliflower mosaic virus (CaMV) 35S promoter and terminator, were used for plant inoculation. A pGEX2T-based plasmid (Amersham Pharmacia Biotech), pGEX-T2b, in which the gene encoding the TAV 2b protein was fused with sequences encoding GST, was used to express GST/TAV2b for RNA-binding assay. Various plasmids used in this study are shown in Figure 1 . Plasmid cDNA clones C1 (previously named pQCD1), C2 (pQCD2), C2 T2B (pQCD2qt), C2 T2BC2a (pQCD2qt1), C2 W2B (pQCD2qw), C3 (pQCD3), T1 (pCass1T1), T2 (pCass1T2), T3 (pCass1T3) and T3 Á163(A) (pCass1T3 Á163(A) ) have all been previously described (26, 39, (41) (42) (43) . The other plasmid cDNA clones were constructed as follows.