Seasonal changes in adenine phosphoribosyltransferase and adenosine kinaseactivities as markers of the dormancy and the growth of Fragaria x ananassa

Because of the potential involvement of adenosine in the winter re-acquisit ion of nucleotide synthesis capability of strawberry plants (Fragaria x ana nassa Duch., Elsanta), the properties and the time-course activity of an ad enosine kinase (EC 2.7.1.20) and an adenine phosphoribosyltransferase (APRT ase, EC 2.4.2.7) of the adenosine recycling pathway were characterized. The results showed an increase in APRTase activity during winter re-acquisitio n of nucleotide synthesis capability and an increase in adenosine kinase ac tivity during spring growth of strawberry plants. Western blot analysis, pe rformed with polyclonal rabbit antibodies raised against peach bud adenosin e kinase, showed a concomitant rise in the strawberry enzyme. These results suggest that APRTase activity could be a good marker of the break of straw berry plant dormancy and adenosine kinase a marker of subsequent spring gro wth. (C) 2000 Editions scientifiques et medicales Elsevier SAS.