PR-10 PROTEIN IS INDUCED BY COPPER STRESS IN ROOTS AND LEAVES OF A CUZN TOLERANT CLONE OF BIRCH, BETULA-PENDULA/

The response of a Cu- and Zn-tolerant birch (Betula pendula) clone to copper stress was investigated. The plants were exposed to control and EC50 concentrations of Cu (0.3 and 30 mu M CuSO4, respectively) for 7 d in hydroponic culture. Total proteins were extracted from the roots and leaves and separated by two-dimensional polyacrylamide gel electr ophoresis, The differences in protein patterns on silver- or Coomassie -stained gels were analysed. The most apparent quantitative difference was the increase in the amount of a 17 kDa polypeptide caused by Cu s tress in both roots and leaves. The protein was identified as Bet v 1- Sc3 (according to the current nomenclature PR-10c) using N-terminal am ino acid sequencing and on-line high-performance liquid chromatography /electrospray ionization/ion trap mass spectrometry. The present resul ts indicate that PR-10 is not only activated by pathogens but also by excessive amounts of copper ions. PR-10 proteins in birch have been re ported earlier not to be induced by Ag, Li or Cd in birch suspension c ulture, but Cu has not been previously tested.