The role of plant CCTα in salt- and osmotic-stress tolerance

To find key genes essential for salt tolerance in the mangrove plant, Bruguiera sexangula, functional screening was performed using Escherichia coli as the host organism. A transformant expressing a cytosolic chaperonin-containing TCP-1alpha (CCTalpha) homologue displayed enhanced salt tolerance. Analysis in E. coli of the functional region revealed that a sequence of only 218 amino acids, containing the apical domain, is necessary for osmotolerance. Furthermore, this domain shows chaperone activity in vitro. Therefore, CCTalpha facilitates the folding of proteins without ATP or the cage-like structure, and may play an important role in stress tolerance, at least in B. sexangula.