Citrus exocortis viroid (CEV): Protein alterations in different hosts following viroid infection.

Polyacrylamide-SDS protein profiles of different CEV-hosts (Gynura aurantiaca DC, tomato, potato, and "Etrog" citron) as altered by the viroid infection are presented. A common feature of leaf protein alteration patterns of all hosts is the intensification of two low molecular weight protein bands (Gynura aurantiaca DC and "Etrog" citron CEV-P1: 13,700 daltons and CEV-P2:18,000 daltons; tomato and potato CEV-P2:12,000 daltons and CEV-P2:16,300 daltons) analogous to those described for CEV-infected Gynura aurantiaca. Although the omnipresence of CEV-P1 and -P2 in all CEV-infected hosts suggests that these proteins may be translation products of CEV-RNA or of its complementary strand, the host-dependent size of CEV-P1 and -P2 and their presence in naturally senescing Gynura plants strongly suggest that neither of the polypeptides are translation products of the CEV-RNA or of any mRNA exclusively related to CEV-host interaction.