Differential Temperature Treatment of Infected Plants

Abstract

The following technique has been developed for synchronisation of virus replication in leaves (Dawson and Schlegel 1973). Inoculated plants are exposed to different temperatures: the lower part with the inoculated leaves to high temperatures (approx. 30 °C), allowing replication of virus, and the upper part to low temperatures (approx. 5 °C), preventing movement of the virus into the upper leaves (temperatures between 5 and 10 °C allowed translocation to top leaves, but were restrictive for replication). After a few days of differential temperature treatment, the plants are transferred to a growth chamber at 25 °C. At that moment (time zero) the “systemic inoculation” starts and the virus enters the vascular system of the top leaves, that is, the phloem of petioles and leaf veins, but cells of the mesophyll do not become infected at the same time. In spite of this lack of synchrony in infection of individual cells, there is relatively synchronous virus replication at the leaf tissue level. Hence, differential temperature treatment is still a valuable technique for studying virus replication and transport.