Beet western yellows virus in border parenchyma cells of Pennycress

Abstract

Beet western yellows virus in vein border parenchyma cells of Pennycress leaves induces some unusual cellular modifications, particularly to the cytoplasmic organelles. Relatively advanced stages of infection were examined in leaves 4 weeks after aphid inoculation with the virus. The most severe ultrastructural modifications occurred in parenchyma cells bordering the veins. The effects included virions in nuclei, virions in cytoplasm, virus vesicles, structural modification to plastids, and appearance of fibrillar inclusions in mitochondria. Oil bodies in the cytoplasm assumed striking proportions. Adjacent cells did not show equivalent changes, and therefore, one may postulate that the border cells show the most adverse effects due to their functional significance in solute transfer.