The Delayed Terminal Flower Phenotype Is Caused by a Conditional Mutation in the CENTRORADIALIS Gene of Snapdragon

• Published in: Plant physiology (Bethesda) Vol. 126; no. 3; pp. 1031 - 1041
• Main Authors: Cremer, Frédéric, Lönnig, Wolf-Ekkehard, Saedler, Heinz, Huijser, Peter
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Biologists 01.07.2001; American Society of Plant Physiologists
• Subjects: Agronomy. Soil science and plant productions; Alleles; Amino Acid Sequence; Antirrhinum majus; Arabidopsis - genetics; Base Sequence; Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; CENTRORADIALIS gene; Development and Hormone Action; DNA Transposable Elements; DNA, Plant; Economic plant physiology; Flowering; Flowering, floral biology, reproduction patterns; Flowers; Fundamental and applied biological sciences. Psychology; Genes, Plant; Genetic loci; Genetic mutation; Growth and development; Inflorescences; Ligands; Magnoliopsida - anatomy & histology; Magnoliopsida - genetics; Magnoliopsida - growth & development; Molecular Sequence Data; Mutation; Phenotype; Phenotypes; Plant physiology and development; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Proteins - physiology; Plant Structures - anatomy & histology; Plants; Protein Conformation; Transposons; Vegetative and sexual reproduction, floral biology, fructification; Flower; Description; Inflorescence; Lateral; Genetic variant; Antirrhinum majus; Delay; Arabidopsis thaliana; Characterization; Allele; Regulation(control); Gene; Three dimensional structure; Cruciferae; Dicotyledones; Morphology; Angiospermae; Scrophulariaceae; Flower crop; Spermatophyta; Property structure relationship; Mutation; Experimental plant
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.126.3.1031

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.