Fig. 12.

Schematic model indicating the pleiotropic role played by βC1 inside the cell affecting the chloroplast structure and function. Localization of the viral protein in the chloroplast leads to ultrastructural damage of the organelle (1). The expression of chloroplast-encoded proteins is hampered, indicating the effect of βC1 on the chloroplast translational machinery localized on the thylakoid membrane (2). Nucleus–chloroplast cross-talk is likely to be affected too as indicated (3). Biosynthesis of the chlorophyll molecule, a thylakoid membrane-bound pathway, was also curtailed (4). Exhaustive interaction of βC1 with the chloroplast led to severe photosynthetic inhibition (5), suppressed defence response (6), and subsequent symptom development. (This figure is available in colour at JXB online.)