ISOLATION AND CHARACTERIZATION OF MESSENGER-RNAS ACCUMULATED DURING IN-VITRO FLOWER BUD FORMATION

The development of vegetative and generative buds on thin-layer explan ts of tobacco (Nicotiana tabacum L. cv. Samsun) has been studied at th e level of translatable mRNA to detect changes in the mRNA population during bud initiation and differentiation, and several quantitative di fferences were found. By differential screening of a cDNA library obta ined from flower-bud-regenerating explants we have isolated a group of six cDNA clones representing genes that are preferentially expressed during in-vitro flower bud formation. Nucleotide sequence analysis of one of these cDNAs, pAP8, showed that the most likely open reading fra me has some typical characteristics of, and homology with, extensin-li ke genes. Northern blot analysis and in-situ hybridization suggest a s pecific role for these extensin-like genes in flower bud initiation on tobacco pedicel explants.