Effect of temperature on symptom expression and accumulation of tomato spotted wilt virus in different host species

Abstract

The effect of two temperature regimes (daytime, 29 ± 2°C, night‐time, 24 ± 3°C; and daytime, 23 ± 1°C, night‐time, 18 ± 2°C) on the symptoms caused by tomato spotted wilt virus (TSWV), and the accumulation of TSWV virions, was compared in Datura stramonium, Nicotiana tabacum cv. White Burley and Physalis ixocarpa. Tobacco plants were more severely affected by TSWV at the high temperature regime, but the incidence (percent of plants with symptoms) was 100% for both regimes. In P. ixocarpa and D. stramonium the higher temperature caused an increase in both incidence and rate of development of symptoms. At high temperature, all three species showed both local and systemic symptoms; however, at low temperature only P. ixocarpa consistently developed systemic symptoms. In general, virus accumulation in the inoculated leaves (presumably the combined effect of virus replication and local movement) of all plants was higher at the lower temperature. Long distance movement in tobacco, leading to virion accumulation in other plant organs, was favoured by high temperature; but there was relatively little effect in P. ixocarpa and D. stramonium.