Cytological changes induced by wheat streak mosaic virus in cereal leaf tissues

Abstract

Cytological changes induced by wheat streak mosaic virus in cereal leaf tissues were studied at the light microscope level. Starting 4–5 days after inoculating the first leaves, a number of cylindrical inclusions were present in the dense cytoplasm of the second wheat leaf epidermal cells. Amorphous inclusions could also be identified in the epidermal cells at late infection stages (from 10 days post inoculation), often associated with deformed nuclei. In mesophyll cells of wheat, barley, and triticale, virus infection induced dense cytoplasm around enlarged nuclei and cytopathie structures within these nuclei. Pyknotic nuclei could be observed at late infection stages. Nuclei and chloroplasts became degraded as the infection progressed. In addition, the cell wall composition was changed and included deposits that were most likely phenolic compounds and lignin. At late infection stages the infected mesophyll cells had collapsed. This was not observed in either senesced virus-free mesophyll cells, or virus-infected epidermal cells. Key words: wheat streak mosaic virus, virus infection, host – virus interaction, cereals, cytological changes, cell wall deposit.