PIF4 — Arabidopsis thaliana

Summary

AT2G43010, designated PIF4 (Phytochrome Interacting Factor 4) in Arabidopsis thaliana on chromosome 2, encodes a basic helix-loop-helix (bHLH) transcription factor that binds phytochrome and acts as a transcriptional activator. PIF4 is associated with the regulation of thermomorphogenesis, shade avoidance, and miRNA transcription, and has been linked to high temperature acclimation, heat stress-induced leaf senescence, and basal thermotolerance. The gene is associated with numerous traits including seedling height, leaf area index, drought recovery, and responses to light quality, UV-A, and far-red light. PIF4 localizes to chromatin, nuclear speckles, and the chloroplast nucleoid, and participates in pathways such as PIF-like-regulated transcription and phytochrome conversion. Studies of related genes in other species connect the family to fruit yield, ripening, lycopene content, cold tolerance, grain yield, and nitrogen metabolism.