A virus isolate was obtained from systemically infected pepper (Capsicum annuum, L.) plants grown under field conditions in Qalubia Governorate, A. It E. According to symptomatology, host range, physical properties, mode of transmission, electron microscopy and serological reactions, the isolated virus was identified as a pepper strain of tomato mosaic virus (ToMV-P). The isolated pepper strain of tomato mosaic virus (ToMV-P) induced local infection followed by systemic symptoms as, mosaic, leaf deformation and stunting on pepper plants cv. “California Wonder”. While sweet and hot peppers “Balady cvs.” and hot pepper cv. "Long Red Cayenne" developed systemic symptoms directly as, mosaic, leaf deformation and stunting. The symptoms were more apparent on sweet pepper cvs. than on hot ones. Host range of this strain was narrow. Most susceptible species to this strain belonged to the Solanaceae with some others in the families (Amaranthaceae and Chenopodiaceae). Chenopodium amaranticolor Caste & Ryn., C. quinoa Willd., Datura metel L., D. stramonium L., Nicotiana glutinosa L., N. tabacum L. cvs. “Samsun, White Burley and Xanthi” showed local infection only. While, Capsicum annuum L. cv. “California Wonder” and Gomphrena globosa L. developed local lesions followed by systemic infection. On the other hand, hosts reacted with systemic infection only comprise, Capsicum annuum L. cvs. “Balady” & “Long Red Cayenne”, Lycopersicon esculentum Mill cvs. “Beto” “UC-97/3”, Physalis floridana Rydb. and Solanum nigrum L. Back inoculation revealed that, the tested members of the families Compositae, Cruciferae, Cucurhitaceae, Euplwrbiaceae, Graminae, Liliaceae, Malvaceae, Leguminosae, Chenopodiaceae except (Chenopodium amaranticolor and C. quinoa) and only Solanum tuberosum L. cvs. “Daimont and Spunta” and S. melongana L. of family Solanaceae, were virus free. Stability in vitro, thermal inactivation point (TIP) lay between 86 and 88°C, dilution end point (DEP) was found to be between 10-5 and 10-6 and longevity in vitro between 63 and 70 days. Mode of transmission of this strain was assayed. The virus was found to be easily transmitted mechanically. This virus strain is not transmit either through seeds of pepper or by aphid (Myzus persicae Sulz.). Electron microscope preparations clearly showed that, the virus strain had rigid rod-shaped particles with a average length of 309 nm and a wide of about 14 nm. SDS-agar double diffusion test indicated that, the virus strain was serologically related to the Tobamovirus group and to some tested pepper strains of Tobamoviruses. The pot experiment carried out under glass-house conditions to determine the response of some pepper cultivars to mechanical inoculation with the isolated virus strain showed that, all tested pepper cvs. were susceptible and statistical analysis revealed that, there were highly significant differences between cvs., so “California Wonder” cv. (sweet pepper) showed the highest percentage of infection (76%) followed by “Balady sweet” cv. (64%) then “Balady hot” cv. (34%), while “Long Red Cayenne” cv. (hot pepper) exhibited the lowest percentage of infection (15%). Hence, the sweet pepper cvs. were more susceptible to artificial infection than hot ones. |
