Mapping phytochromes-PIFs interaction network

PABLO D. CERDÁN; GUADALUPE RODRIGUEZ FERRANTE; MAXIMILIANO SANCHÉZ-LAMAS

Rosario

Simposio; Simposio de Genomica Funcional de Plantas; 2017

IBR

Plants sense and respond to environmental conditions such as temperature and light. The molecular mechanisms involved in those processes are of great interest for both basic and applied sciences. It is known that Arabidopsis has 13 photoreceptors capable of perceiving from UV to Far Red light. Phytochromes (phys) are a small family of five members (phyA-E), which particularly perceive red and far red light. Phys interact, downstream, with a group of seven bHLH transcription factors called Phytochrome-Interacting Factors (PIF1, PIF3-8). PIFs belong to a bigger family of 15 bHLH which has their DNA binding domain highly conserved. Although not much is know about close PIFs homologs, the interaction between them, and phys and PIFs can not be ruled out. As both phys and PIFs dimerize with different members of their respective families, the number of possible interactions between both families is enormous. We think that this combinatorial variability might explain the plasticity of plants? response to environmental signals. That is the reason why, using BiFC and FRET assays, we are studying interaction network between phys and PIFs. First we used BiFC assay to test which dimers of PIFs (or PIF homologs) are viable in vivo. Then, we combined BiFC and FRET assays to test if PIFs interact differentially with particular phys dimers. The results show a high number of interaction among PIFs and some differences between phys dimers and their interaction with PIFs, which could explain the specificity of some phytochrome pairs.