Plant Physiol, July 2001, Vol. 126, pp. 1031-1041
The Delayed Terminal Flower Phenotype Is Caused by a Conditional
Mutation in the CENTRORADIALIS Gene of Snapdragon
Frédéric
Cremer,*
Wolf-Ekkehard
Lönnig,
Heinz
Saedler, and
Peter
Huijser
Max-Planck Institut für Züchtungsforschung,
Carl-von-Linné Weg 10, 50829 Köln, Germany
The snapdragon (Antirrhinum majus)
centroradialis mutant (cen) is
characterized by the development of a terminal flower, thereby replacing the normally open inflorescence by a closed inflorescence. In
contrast to its Arabidopsis counterpart, terminal
flower1, the cen-null mutant displays an almost
constant number of lateral flowers below the terminal flower. Some
partial revertants of an X-radiation-induced cen mutant
showed a delayed formation of the terminal flower, resulting in a
variable number of lateral flowers. The number of lateral flowers
formed was shown to be environmentally controlled, with the fewer
flowers formed under the stronger flower-inducing conditions. Plants
displaying this "Delayed terminal flower" phenotype were found to
be heterozygous for a mutant allele carrying a transposon in the coding
region and an allele from which the transposon excised, leaving behind a 3-bp duplication as footprint. As a consequence, an iso-leucine is
inserted between Asp148 and Gly149 in the CENTRORADIALIS protein. It is
proposed that this mutation results in a low level of functional CEN
activity, generating a phenotype that is more similar to the Arabidopsis Terminal flower phenotype.
*
Corresponding author; e-mail cremer{at}mpiz-koeln.mpg.de; fax
49-0221-5062-113.
© 2001 American Society of Plant Physiologists
