Der cytoplasmatische Signalweg Phytochroms in niederen Pflanzen

• Antragsteller: Professor Jonathan Hughes, Ph.D.
• Fachliche Zuordnung: Zell- und Entwicklungsbiologie der Pflanzen ; Pflanzenphysiologie
• Förderung: Förderung von 2006 bis 2019
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 22237773

Phytochrome photoreceptors play a central role in regulating plant development. In its ground state (Pr) phytochrome is cytosolic but red light absorption induces the Pfr signalling state which then moves into the nucleus to regulate transcription. Clearly, however, some phytochrome effects occur far too quickly for such a mechanism. Moreover, in lower plants phytochrome provides vectorial information for directional growth (photo- and polarotropism) of individual cells: this certainly cannot be based on transcription regulation. Thus phytochrome has a second, much more rapid signalling system within the cytoplasm. The goal of this project is to discover the nature of this system. We have studied the directional light responses and cloned the phytochrome genes in the moss Physcomitrella. As, uniquely amongst plants, high rates of homologous recombination in mosses allow specific genes to be targeted for mutation, we could identify the specific Physcomitrella phytochrome - PP4 - responsible for direction sensing. The proposed project will exploit the genetics of Physcomitre//a to uncover the particular molecular feature(s) of PP4 responsible for this and use appropriate methods to identify PP4 s cytoplasmic partners. Fluorescence labelling will allow PP4 and its partners to be localised in the cell, giving clues as to the action mechanism. Fluorescence dichroism will allow us to detect the anisotropic orientation required by formal models of polaro- and phototropism. The project will make extensive use of the Physcomitrella genome sequence which will shortly become available.

• DFG-Verfahren: Sachbeihilfen
• Beteiligte Personen: Dr. Thomas Gensch; Professor Dr. Günter Lochnit; Professor Dr. Stefan A. Rensing