THE PLANT CELL, Vol 2, Issue 10 963-972, Copyright © 1990 by American Society of Plant Biologists
Identification of Genes Expressed in the Tobacco Shoot Apex during the Floral Transition
A. J. Kelly, M. T. Zagotta, R. A. White, C. Chang and D. R. Meeks-Wagner
Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403
The shoot apex of higher plants contains undifferentiated meristematic
cells that serve as the origin of post-embryonic organs. The transition
from vegetative to reproductive growth results in the commitment of the
apical meristem to floral organ formation. To identify the molecular
signals that initiate floral development, we have pursued the isolation of
genes that are transcriptionally active in the shoot apex of tobacco during
the transition from vegetative to floral growth. The small size of the apex
led us to utilize polymerase chain reaction technology for the differential
screening of an unamplified, subtracted cDNA library made from transition
shoot apices. This approach enabled the isolation of the apex-specific and
floral apex-specific cDNA clones described in this paper. One clone, A3,
detected an equivalent level of transcript in the shoot apex during all
developmental stages observed. The second clone, FA2, detected a unique
transcript that increased in abundance in the shoot apex during the
transition to flowering and showed high levels of expression in developing
petals, stamens, and pistils.
