ISHS Acta Horticulturae 386: XVI International Symposium on Fruit Tree Virus diseases
CYTOPATHOLOGICAL STUDY OF THE DOUBLE-MEMBRANE BODIES OCCURRING IN FIG PLANTS AFFECTED BY FIG MOSAIC DISEASE. |
| Authors: | A. Appiano, M. Conti, N. Zini |
| Abstract:
Cytological observations of fig leaves affected by fig mosaic disease confirmed the presence of typical double-membrane bodies (DMBs), possibly representing the disease agent in the cytoplasm of parenchyma cells. They contained dense nucleoids, fine fibrils and ribosome-like particles and were often associated with characteristic matrices, consisting of aggregates of electrondense tubules. DMBs and matrices showed a specific association with endoplasmic reticulum (ER) and Golgi vesicles. The double envelope of DMBs reacted positively to silver proteinate, as did matrices, ER and dictyosomes, indicating the presence of carbohydrates. Postembedding RNase- and DNase-gold cytochemistry, aimed to identify nucleic acid(s) inside DMBs, did not give conclusive results. On grounds of size, morphology and intracellular behaviour, DMBs appear quite different from any known plant pathogen. Some possible similarities with pathogens not known to infect plants, such as poxviruses and Chlamydiae, are briefly discussed. | |
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