Isolation of a CONSTANS ortholog from Pharbitis nil and its role in flowering.
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.
Liu
J
J
Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, Michigan 48824-1312, USA.
Yu
J
J
McIntosh
L
L
Kende
H
H
Zeevaart
J A
JA
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D029681:Arabidopsis Proteins; D001483:Base Sequence; D002940:Circadian Rhythm; D018548:Cotyledon / Q000502:physiology; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics*; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D005816:Genetic Complementation Test; D007438:Introns; D008027:Light; D008969:Molecular Sequence Data; D017440:Photoperiod; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D018547:Plant Stems / Q000502:physiology; D030821:Plants, Genetically Modified / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D019657:Solanaceae / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics*
D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; D010940:Plant Proteins; D014157:Transcription Factors