title: Convergence of light and chloroplast signals for de-etiolation through ABI4-HY5 and COP1.
abstract: Seedling de-etiolation prepares plants to switch from heterotrophic to photoautotrophic growth, a transition essential for plant survival. This delicate de-etiolation process is precisely controlled by environmental and endogenous signals. Although intracellular plastid-derived retrograde signalling is essential for the de-etiolation process, the molecular nature of these retrograde signals remains elusive(1-3). Here we show that chloroplast and light signals antagonistically fine-tune a suite of developmental and physiological responses associated with de-etiolation through a transcriptional module of ABA INSENSITIVE 4 (ABI4) and ELONGATED HYPOCOTYL 5 (HY5). Moreover, ABI4 and HY5 antagonistically regulate the expression of CONSTITUTIVE PHOTOMORPHOGENIC1 (COP1) and the subsequent greening process. In turn, ABI4 and HY5 are targeted for degradation by COP1 in the light and dark, respectively, to ensure a proper interplay of ABI4 and HY5 actions during seedling de-etiolation. Our study provides a new molecular mechanism for understanding how chloroplast signals converge with light signals to optimize early plant development.
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Xiumei
authors.initials: X
authors.lastname: Xu
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chi
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Xuwu
authors.initials: X
authors.lastname: Sun
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Peiqiang
authors.initials: P
authors.lastname: Feng
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Hailong
authors.initials: H
authors.lastname: Guo
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Rongcheng
authors.initials: R
authors.lastname: Lin
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Congming
authors.initials: C
authors.lastname: Lu
authors.affiliation: Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, 100081, China.
authors.forename: Haiyang
authors.initials: H
authors.lastname: Wang
authors.affiliation: Plant Molecular Biology (Botany), Department Biology I, Ludwig-Maximilians-University, 82152 Planegg, Germany.
authors.forename: Dario
authors.initials: D
authors.lastname: Leister
authors.affiliation: Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Zhang
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D050976:Basic-Leucine Zipper Transcription Factors / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000502:physiology; D064527:Etiolation; D018506:Gene Expression Regulation, Plant; D008027:Light; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D036226:Seedlings / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases
chemical_list: C470421:ABI4 protein, Arabidopsis; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; C109254:HY5 protein, Arabidopsis; D009687:Nuclear Proteins; D014157:Transcription Factors; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases