ISHS Acta Horticulturae 551: IX International Symposium on Small Fruit Virus Diseases
PHYTOPLASMAS ASSOCIATED WITH TOMATO STOLBUR DISEASE |
| Authors: | M.A. Favali, L. Sanità di Toppi, C. Vestena, F. Fossati, R. Musetti |
| Keywords: | Phytoplasma, Tomato, Electron microscopy, Protein determination. |
| Abstract:
In this paper we report observations on the ultrastructural alterations caused by stolbur phytoplasmas on leaves, fruits and seeds of naturally and artificially infected tomatoes (Lycopersicon esculentum Miller) and in periwinkle (Catharanthus roseus L.), used as test plant. Particular attention has been given to the study by electron microscopy of possible stolbur-induced stress proteins to ascertain their localisation. SDS-PAGE was used to investigate the presence and nature of stress proteins. TEM observations confirmed the presence of phytoplasmas in the phloem cells of tomato leaves naturally infected in the field, in periwinkle and in back-infected tomatoes. A few phytoplasmas were noticed in the fruits, while no phytoplasmas were detected in the seed tissues. Accumulation of proteinaceous material was observed in the phloem of infected plants and the cell walls were distorted and thicker than in the controls plants. In silver-stained SDS-PAGE gels of extracts from stolbur-infected leaves, a marked protein band of about 70 kDa appeared, slightly present in the non-infected material. This 70 kDa band might be a preliminary indication of a specific protein unique to stolbur-infected material. | |
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