Submitted to: Phytopathologia Mediterranea
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/24/1998
Publication Date: N/A
Interpretive Summary: Tomato plants in southern Italy are affected by a serious disease in which plants become stunted, leaves become yellow or reddish, flower petals become green, and yield of tomato fruits is markedly reduced. We have found that diseased plants are infected by a phytoplasma. Phytoplasmas are tiny bacteria that have no rigid cell wall; they are known only in plants and in the insects that spread them from plant to plant in the field. By using molecular techniques, we identified and characterized the phytoplasma in diseased tomatoes in Calabria as the stolbur phytoplasma. This phytoplasma also causes a very severe disease of grapevines in Italy and other Mediterranean countries. Our work will aid scientists, plant disease diagnosticians, and farmers, because it provides a critical first step toward understanding and eventually managing the spread of the tomato stolbur disease in southern Italy and other regions.
Technical Abstract: Tomato diseases characterized by erect growth and stunting of plants, yellowing or reddening of leaves, proliferation of lateral shoots, hypertrophied calyx, greening of flower petals have been reported by several authors in many regions of Italy (Ciccarone, 1951; Grancini, 1959, 1963; Martelli et al., 1969; Ragozzino et al., 1977; Lovisolo et al., 1982; Polizzi et al., 1990). Electron microscopic observations of infected tomato plants have shown the presence of wall-less prokaryotic organisms in such plants (Martelli et al., 1969; Belli et al., 1972; Lovisolo et al., 1982; Lovisolo et al., 1982; Polizzi et al., 1990), but the identity of the organisms reported in these papers was not determined. During a survey performed in Southern Italy (Calabria), tomato plants showing typical yellows-type symptoms were observed in several commercial tomato growing areas located in Catanzaro and Cosenza Provinces, with an incidence ranging from 1 to 12%. Electron microscopic observations revealed the presence of phytoplasma cells in the phloem sieve tubes of those symptomatic tomato plants. Molecular detection and characterization of phytoplasmas associated with such diseases tomato plants in Calabria were accomplished and results (previously communicated by Albanese et al., 1996) are here reported.