WESTERN BLOTTING ANALYSIS OF THE PLUM POX VIRUS CAPSID PROTEIN

Abstract

Immunoblotting using a polyclonal antiserum to Plum pox virus (PPV) was used to detect PPV capsid protein (CP) in different parts of mechanically infected Nicotiana benthamiana plants from 1 to 21 days post inoculation (dpi). The velocity of viral spread in infected plants depended only slightly on the inoculum concentration. Roots and tops of the plants became infected 5- 7 dpi. Systemic infection of non-inoculated leaves in the middle part of the plants was detected later (7-10 dpi), but infective viral RNA proved to be there 1 dpi. Comparing several isolates of PPV strains M, D and Rec, the fastest infection movement was detected for PPV-Rec, the slowest for PPV-D. Differences in the CP electrophoretic mobility among the strains M, D and Rec did not correspond to their amino acid sequences. Posttranslational CP glycosylation and phosphorylation was detected in six PPV isolates We presume the the nonamino acid compounds linked to the N termini are responsible for the electrophoretic pattern differences among the studied isolates.