title: Salicylic acid influences Hsp70/Hsc70 expression in Lycopersicon esculentum: dose- and time-dependent induction or potentiation.
abstract: Overexpression of heat-shock (HS) proteins (HSP) is often sufficient to protect against lethal environmental stresses. Anti-inflammatory salicylates potentiate the induction of the 70 kDa HSP (Hsp70) in mammals in response to HS and enhance thermotolerance. In plants, salicylic acid (SA) is a natural signalling molecule, mediating resistance in response to avirulent pathogens. The influence of SA on the HS response in plants is, however, unknown. We investigated the effect of SA, alone or with HS, on Hsp70/Hsc70 expression in tomato cells using biometabolic labelling and Western blotting. A dose- and time-dependent influence on Hsp70/Hsc70 accumulation was observed: SA at 1.0 mM (3 h) potentiated heat-induced accumulation, while 1.0 mM (5 h) and 0.5 mM (8 h) induced expression, the latter preceded by increased membrane permeability. These results suggest that in plants, as in mammals, low SA concentrations do not induce Hsp70/Hsc70 expression but potentiate HS induction and confer membrane protection, while cytotoxic levels induce Hsp70/Hsc70.
authors.affiliation: Department of Chemistry and Biochemistry, Rand Afrikaans University, Auckland Park, 2006, South Africa.
authors.forename: M J
authors.initials: MJ
authors.lastname: Cronjé
authors.forename: L
authors.initials: L
authors.lastname: Bornman
mesh_terms: D002352:Carrier Proteins / Q000378:metabolism*; D002463:Cell Membrane Permeability / Q000187:drug effects; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000378:metabolism*; D006358:Hot Temperature; D018551:Solanum lycopersicum / Q000187:drug effects* / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism*; D020156:Salicylic Acid / Q000494:pharmacology*
chemical_list: D002352:Carrier Proteins; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D010940:Plant Proteins; D020156:Salicylic Acid