Phytochrome B triggers light-dependent chromatin-remodeling through the PRC2-associated PHD finger protein, VIL1

To compensate for a sessile nature, plants have developed sophisticated mechanisms to sense varying environmental conditions. Phytochromes (phys) are light and temperature sensors that regulate downstream genes to render plants responsive to environmental stimuli(1-4). Here, we show that phyB directly triggers the formation of a repressive chromatin loop by physically interacting with VIN3-LIKE1/VERNALIZATION 5 (VIL1/VRN5), a component of the Polycomb Repressive Complex 2 (PRC2)(5, 6), in a light-dependent manner. phyB and VIL1 cooperatively contribute to the repression of growth-promoting genes through the enrichment of Histone H3 Lys 27 trimethylation (H3K27me3), a repressive histone modification. In addition, phyB and VIL1 mediate the formation of a chromatin loop to facilitate the repression of ATHB2. Our findings show that phyB directly utilizes chromatin remodeling to regulate the expression of target genes in a light-dependent manner.