ISOLATION, SEQUENCING AND ANALYSIS OF THE EXPRESSION OF BRYONIA CALMODULIN AFTER MECHANICAL PERTURBATION

A cDNA clone (Bc329) encoding calmodulin was isolated from a Bryonia c DNA library by screening with cloned Arabidopsis calmodulin cDNA. The cDNA Bc329 was 899 bp full-length clone. The predicted amino acid sequ ence consists of 149 residues and reveals a high homology with other k nown plant calmodulins (91 to 99% identity). Genomic southern blot sug gests that Bryonia calmodulin is encoded by a single-copy gene. The Bc 329 clone was used as a probe to study the expression of calmodulin mR NA after a mechanical stimulus applied on young Bryonia internodes. Th e steady-state of calmodulin mRNA reached a maximum 30 min after the t reatment before it progressively decreased. The role of calcium and ca lmodulin as second messengers is discussed with regard to environmenta l changes.