2. Juni 2015: Kishore Panigrahi, Plant Biology Lab, Odisha, India
Talk in the biologic colloquium: "Phosphorylation of CONSTANS regulates its COP1-dependent abundance during the photoperiodic regulation of flowering in Arabidopsis thalian"
Was |
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Wann |
02.06.2015 von 16:15 bis 17:30 |
Wo | Lecture Hall Zoology, Hauptstr. 1 |
Name | Esther Kogon |
Termin übernehmen |
vCal iCal |
Abstract:
Photoperiodic flowering involves responses to changing day length through a master regulator transcription factor CONSTANS (CO). The accumulation of this CO protein promotes flowering in long days of spring and summer. Late flowering occurs in short days due to its degradation by CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) E3 ligase complex. In this current report we show that a portion of CO is phosphorylated. Although both the Phosphorylated and unphosphorylated forms are detected throughout the diurnal cycle but their ratio changes. The relative abundance of the phosphorylated form is higher in the light phase of diurnal cycle. This changes in their relative abundance controlled by COP1. Similarly, In the cop1 mutant the phosphorylated form is far more abundant. In photoreceptor triple mutants (phyA cry1 cry2) background unphosphorylated CO is the more abundant leading it to later flowering. This effect is caused by increased activity of COP1 as it is overcome by introduction of the cop1 mutation in the cop1 phyA cry1 cry2 quadruple mutant. CO is also degraded in red light and as in darkness this increases the relative abundance of unphosphorylated CO. Therefore, we propose that Phosphorylated CO modulates the earlier flowering response that is fine tuned by the activity of COP1.