Thermal inactivation of tomato spotted wilt tospovirusin vivo

Abstract

The effectin vivoof temperatures that are near thein vitrothermal inactivation point of tomato spotted wilt tospovirus (TSWV) was studied in tobacco plants systemically infected with the virus.In vitrothe isolate used was infective after 10 min at 44 °C, but not at 46 °C.In vivothe virus was infective in plants treated for 1 h at 50 °C. However, the virus was inactivated in plants held for 24 h at 45 °C, with light for 14 h, but not after 14 h at 45 °C in the light. After 24 h at 45 °C in the dark the virus was inactivated only in 30% of the plants. Reactivity of the nucleocapsids and glycoprotein G1 with two specific monoclonal antibodies reacting only with the native antigens was not affected by temperature treatments inactivating the virusin vitroandin vivo. Our results suggest a specific involvement of some chemical compounds formed at high temperature in the light in the inactivation of TSWVin vivorather than a simple thermal inactivation effect. This appears to be the first report of successful thermotherapy of TSWV-infected plants.