ELONGATION-FACTOR 1-ALPHA (EF-1-ALPHA) TRANSCRIPT LEVELS ARE DEVELOPMENTALLY AND ENVIRONMENTALLY REGULATED IN APPLE PLANTS

A cDNA fragment corresponding to an elongation factor 1 alpha subunit (EF-1 alpha) messenger was amplified and used to isolate a correspondi ng full-length copy from an apple (Malus domestica [L.] Borkh) cv. McI ntosh 'Wijcik' cDNA library. Genomic Southern blot analysis using this probe confirmed that the EF-1 alpha factor is encoded by a multigenic family in apple. Northern blot analysis of corresponding transcript l evels in apple tree organs at various developmental stages revealed th at very young leaves contain higher levels of EF-1 alpha mRNA than old er leaves, although significant levels could be detected in all organs tested. In response to wounding, a transient decrease in EF-1 alpha m RNA levels was observed in apple plantlets, followed by a slight incre ase. A 24-h incubation at low temperature (5 degrees C) induced a sign ificant decrease in corresponding transcript abundance. In contrast, w hen dark-grown, etiolated, apple plantlets were transferred to light c onditions and analyzed with the same probe, few modifications in EF-1 alpha transcript abundance were detected.