Evolution of phytochrome signalling and nuclear transport

• Applicant: Professor Dr. Andreas Hiltbrunner
• Subject Area: Plant Physiology
• Term: from 2008 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 80790529

In seed plants the phytochrome A (phyA) photoreceptor plays a key role in survival in far-red light enriched environments and it is essential for responses to very low intensities of light. After activation by light phyA binds to FHY1, which mediates phyA nuclear transport and accumulation. In contrast, cryptogam phys are believed to be cytosolic and/or membrane associated proteins. Although the split of the phy gene lineage into phyA and other phys occurred only in seed plants FHY1 like proteins can be identified in ferns, mosses and green algae, which do not contain phyA like phys. All these cryptogam FHY1 proteins interact with phyA as well as with cryptogam phys. Interestingly, also other key components of phyA signalling are represented in the Physcomitrella genome suggesting that phyA may have adopted a pre-existing signalling system from cryptogams and that also cryptogam phys have a function in the nucleus. Transgenic Physcomitrella lines expressing YFP tagged phys will be employed to test this hypothesis. Moreover, the FHY1 binding site of phyA/cryptogam phys will be mapped using a random mutagenesis/Y2H approach, which will provide further insight into how phyA signalling and the phy/FHY1 system evolved.

• DFG Programme: Research Grants