Expression of several genes encoding chaperone proteins in response to mechanical perturbation inBryonia dioica internodes

Mechanical stress exerted on youngBryonia dioica internodes which resulted in reduced elongation and increased radial expansion induced a rapid and transient increase in specific mRNAs. Hybridizations were performed using ubiquitin, cyclophilin and heat-shock protein cDNAs as probes on RNA extracted at successive time intervals in control and rubbed internodes. Changes in ubiquitin and cyclophilin were rapidly enhanced after mechanical perturbation. Levels of mRNAs reached a maximum 0.5 h and 1.5 h after rubbing and then decreased. The heat shock protein gene was constitutively expressed; it was however slightly stimulated following the rubbing treatment. All the three genes encoded for molecular chaperones and they were regulated in response to environmental stimuli. The role of chaperones was discussed with regard to the plant response to several natural stresses.