Arabidopsis DE-ETIOLATED1 Represses Photomorphogenesis by Positively Regulating Phytochrome-Interacting Factors in the Dark

• Published in: The Plant cell 2014-09, Vol.26 (9), p.3630-3645
• Main Authors: Dong, Jie, Tang, Dafang, Gao, Zhaoxu, Yu, Renbo, Li, Kunlun, He, Hang, Terzaghi, William, Deng, Xing Wang, Chen, Haodong
• Format: Article
• Language: English
• Subjects: Arabidopsis; Arabidopsis - drug effects; Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; Cell Wall - drug effects; Cell Wall - radiation effects; Cocktails; Darkness; Etiolation - drug effects; Etiolation - radiation effects; Gene expression regulation; Gene Expression Regulation, Plant - drug effects; Gene Expression Regulation, Plant - radiation effects; Genes; Genes, Plant; Hypocotyls; Indoleacetic Acids - pharmacology; Light; Models, Biological; Morphogenesis - drug effects; Morphogenesis - radiation effects; Mutation - genetics; Nuclear Proteins - metabolism; Phenotype; Phenotypes; Photosynthesis - drug effects; Photosynthesis - radiation effects; Physiological regulation; Plant cells; Plants; Proteasome Inhibitors - pharmacology; Protein Binding - drug effects; Protein Binding - radiation effects; Seedlings; Seedlings - drug effects; Seedlings - metabolism; Seedlings - radiation effects; Transcription factors; Transcriptome - genetics
• ISSN: 1040-4651; 1532-298X
• DOI: 10.1105/tpc.114.130666

Arabidopsis thatiana seedlings undergo photomorphogenic development even in darkness when the function of DEETIOLATED1 (DET1), a repressor of photomorphogenesis, is disrupted. However, the mechanism by which DET1 represses photomorphogenesis remains unclear. Our results indicate that DET1 directly interacts with a group of transcription factors known as the phytochrome-interacting factors (PIFs). Furthermore, our results suggest that DET1 positively regulates PIF protein levels primarily by stabilizing PIF proteins in the dark. Genetic analysis showed that each pif single mutant could enhance the det1-1 phenotype, and ectopie expression of each PIF in det1-1 partially suppressed the det1-1 phenotype, based on hypocotyl elongation and cotyledon opening angles observed in darkness. Genomic analysis also revealed that DET1 may modulate the expression of light-regulated genes to mediate photomorphogenesis partially through PIFs. The observed interaction and regulation between DET1 and PIFs not only reveal how DET1 represses photomorphogenesis, but also suggest a possible mechanism by which two groups of photomorphogenic repressore, CONSTITUTIVE PHOTOMORPHOGENESIS/DET/FUSCA and PIFs, work in concert to repress photomorphogenesis in darkness.