Expression of one of the members of the Arabidopsis chaperonin 60 beta gene family is developmentally regulated and wound-repressible.

To study the pattern of gene regulation of the plastid chaperonin 60 beta gene family a chimaeric gene was constructed fusing the 5'-flanking region of the chaperonin 60 beta B3 gene to the beta-glucuronidase reporter gene. Histochemical and fluorometric analysis of the GUS activity present in transgenic plants harbouring this gene construct showed that the B3 promoter is expressed in leaves, stem, petioles and several flower tissues. The pattern of cell type-specific expression in stems and flowers was found to be developmentally regulated. Expression of the B3 promoter was found not to be heat-inducible, but highly repressed by wounding. The rapid decay in GUS activity upon wounding indicates that, at least under some physiological conditions, the gene product of this reporter gene is not as stable as has been previously thought.