Isolation of a CONSTANS Ortholog from Pharbitis nil and Its Role in Flowering

• Published in: Plant physiology (Bethesda) Vol. 125; no. 4; pp. 1821 - 1830
• Main Authors: Jiayou Liu, Jianping Yu, McIntosh, Lee, Kende, Hans, Jan A. D. Zeevaart
• Format: Journal Article
• Language: English
• Published: Rockville, MD American Society of Plant Physiologists 01.04.2001; American Society of Plant Biologists
• Subjects: Amino Acid Sequence; amino acid sequences; Arabidopsis; Arabidopsis - genetics; Arabidopsis Proteins; Base Sequence; Biological and medical sciences; Biology and morphogenesis of the reproductive apparatus. Photoperiodism, vernalisation; chemistry; Circadian Rhythm; Circadian rhythms; Complementary DNA; Cotyledon; Cotyledon - physiology; Cotyledons; Darkness; Development and Hormone Action; DNA-Binding Proteins; DNA-Binding Proteins - chemistry; DNA-Binding Proteins - genetics; duration; Flowering; Flowers; Fundamental and applied biological sciences. Psychology; gene expression; Gene Expression Regulation, Plant; Genes; Genetic Complementation Test; genetics; Introns; Ipomoea nil; Light; Messenger RNA; Molecular Sequence Data; mutants; Photoperiod; physiology; Plant physiology and development; Plant Proteins; Plant Proteins - chemistry; Plant Proteins - genetics; Plant Stems; Plant Stems - physiology; Plants; Plants, Genetically Modified; Plants, Genetically Modified - physiology; Reverse Transcriptase Polymerase Chain Reaction; RNA; Scotophase; Seedlings; Sequence Alignment; Sequence Homology, Amino Acid; Solanaceae; Solanaceae - genetics; Solanaceae - physiology; Transcription Factors; Transcription Factors - chemistry; Transcription Factors - genetics; Vegetative and sexual reproduction, floral biology, fructification; Environmental factor; Photoperiod; Gene expression; Convolvulaceae; Induced flowering; Regulation(control); Gene; Pharbitis nil; Dicotyledones; Light; Angiospermae; Flowering; Isolation; Spermatophyta; Experimental plant
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.125.4.1821

The short-day plant Pharbitis nil is a model plant for the study of photoperiodic control of floral initiation. Flower formation can be induced at the cotyledon stage by a single long night of at least 14 h in duration. Using differential display of mRNA we identified a P. nil ortholog of the Arabidopsis CONSTANS (CO) gene, which will be referred to as PnCO. Expression of PnCO was high after a 14-h night, but low when the dark period was 12 h or less. Our results indicate that the level of the PnCO transcript is photoperiodically regulated. After transfer from continuous light to darkness, PnCO showed a circadian pattern of expression. Expression of the CAB gene, which is a molecular marker for the circadian clock, exhibited a different pattern of expression than did PnCO and was not subject to the same photoperiodic control. A major portion of the PnCO transcripts contained an unspliced intron. Only the intron-free PnCO was able to complement the co mutant of Arabidopsis by shortening the time to flower.