The role of photoreceptors in the regulation of proteins that control flowering-time in Arabidopsis

• Applicant: Privatdozent Dr. Wim Soppe
• Subject Area: Plant Cell and Developmental Biology
• Term: from 2004 to 2005
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5426853

The photoperiodic promotion pathway in Arabidopsis detects long-day signals and mediates flowering initiation. Photoreceptors are essential in this pathway and have a role both in the entrainment of the circadian clock and in the direct regulation of flowering-time genes. The CONSTANS (CO) gene has a central place in the photoperiodic promotion pathway. Expression and protein studies have shown that CO is regulated at both the transcriptional and post-transcriptional levels by the circadian clock and signals from photoreceptors respectively. This project aims to identify the nature of these signals and to relate their function with the role of CO in the induction of flowering. GIGANTEA (GI) is another flowering-time gene from the photoperiodic pathway that functions downstream of the circadian clock and of phytochrome and which is involved in transcription of CO. The transcriptional regulation of CO will be studied by the identification of novel genes that are required for the function of GI and play a role in the signalling pathway upstream of CO. These genes will be selected from a suppressor mutagenesis of GI overexpressor plants. Study of the post-transcriptional regulation of CO wil focus on the mechanism by which photoreceptors antagonistically regulate CO abundance and on the identification of proteins that are involved in the active degradation of CO.

• DFG Programme: Research Grants