PHYTOCHROME INTERACTING FACTORs Trigger Environmentally Responsive Chromatin Dynamics

The pivotal interplay between light receptors and PHYTOCHROME INTERACTING FACTORs (PIFs) serves as an essential regulatory hub that perceives and integrates environmental cues into the plant’s transcriptional networks. A critical control component of environmentally-responsive gene networks is the histone variant H2A.Z which provides transcriptional plasticity and prevents undesired gene activation. However, the functional relationship between PIF transcription factors and H2A.Z is only poorly understood. Here, we describe a genomic approach that utilizes the rapid and reversible light-mediated manipulation of PIF7 activity to visualize PIF7 DNA binding and H2A.Z occupancy kinetics. Strikingly, PIFs shape the H2A.Z landscape in a light quality-dependent manner. In addition, we observed that PIFs initiate H2A.Z eviction through direct interaction with EIN6 ENHANCER (EEN), a subunit of INO80 chromatin remodeling complex. These studies uncover a previously unknown PIF-INO80 regulatory module controlling plant growth in response to rapid environmental changes. One-sentence summary A PIF-INO80 module controls light quality-dependent H2A.Z dynamics.