PHASE-CHANGE IN PRUNUS-AVIUM - DIFFERENCES BETWEEN JUVENILE AND MATURE SHOOTS IDENTIFIED BY 2-DIMENSIONAL PROTEIN SEPARATION AND IN-VITRO TRANSLATION OF MESSENGER-RNA

Differences in protein content and translatable mRNA between shoot tip s of juvenile and mature Prunus avium L. cv. Stella were analysed. Sam ples were taken from self-pollinated seedlings and rooted cuttings fro m the crown of the mature parent tree growing under the same condition s in a controlled environment cabinet, and directly from the branches of the parent tree in the field. 2-dimensional polyacrylamide gel elec trophoresis profiles of a protein fraction enriched for membrane prote ins and in vitro translation products of extracted messenger RNA were examined. Some proteins were found to differ in relative abundance in a phase-dependent manner. Comparison of in vitro translation products also revealed differences in the abundance of specific messenger RNA t ranscripts. A phase-dependent protein was purified from PAGE gels and N-terminal amino acid sequence data were obtained. This 12 kDa protein , which was expressed at higher levels in juvenile shoot tips, showed sequence homology with a 40 kDa subunit of the enzyme 5-aminolevulinic acid dehydratase (EC 4.2.1.24) from higher plants.