Mutants of Tobacco mosaic virus with Temperature-Sensitive Coat Proteins Induce Heat Shock Response in Tobacco Leaves

Abstract

We analyzed, with respect to heat shock proteins (HSPs), systemically reacting tobacco leaves inoculated with Tobacco mosaic virus (TMV), wild-type vulgare, and temperature-sensitive coat protein (CP) mutants Ni 118 (P20L) and flavum (D19A), kept at 23 or 30°C. HSP18 and HSP70 mRNAs and proteins were induced with temperature-sensitive CP mutants after 1 to 2 days at 30°C. After 4 to 6 days, HSP70 was also induced at 23°C. The induction of HSPs paralleled the amount of insoluble TMV CP in leaf extracts, indicating that denatured TMV CP by itself induces a heat-shock response.