FIG. 8.

Locations of some of the mutations that affect aphid transmission and movement within the plant. The C-α backbones of one of the A, B, and C subunits are shown in blue, green, and red, respectively. The surrounding icosahedrally related subunits are shown in gray. The nearest five- and threefold (quasi-sixfold [Q6]) axes are labeled. The positions of the various mutation sites are represented by colored spheres. P129, represented by yellow balls, appears to be involved in aphid transmission and host symptomalogy. S129F can be compensated for by mutations that lie on αEF (residues 138, 144, and 147), represented by black balls. Mutations at A162 (cyan balls) affect aphid transmission, perhaps by decreasing capsid stability. The destabilizing effects of deleting residues 15 to 40 can be partially circumvented by the mutations at residues 81, 166, and 173, denoted by mauve balls.