“…DNAs of the Cabb S, NY8153, W and CM4-184 CaMV isolates were obtained from plasmids pCa37 (Lebeurier et al, 1982), pCMS31 (Armour et al, 1983), pLW303X (Walden & Howell, 1982;Choe et aL, 1985) and pLW414 (Howell et al, 1980), respectively, pCaDH was constructed as described by Armour et aL (!983) from DNA extracted from virions obtained from turnip plants infected with the D/H isolate of CaMV (Balazs et al, 1982). 'Fwo derivatives of pCa37, each bearing a small alteration in open reading frame (ORF) III, were used: pUMI30 (Melcher et al, 1986b) and pXZG ( Fig. 1) (Choe et al, 1985).…”