title: Arabidopsis LEAFY COTYLEDON1 Mediates Postembryonic Development via Interacting with PHYTOCHROME-INTERACTING FACTOR4.
abstract: Plants undergo postembryonic growth during the developmental transition from germinating seeds to seedlings. Recent studies suggest LEAFY COTYLEDON1 (LEC1), initially identified as a central regulator in embryogenesis and seed maturation in Arabidopsis thaliana, plays a distinct role in postembryonic development. However, the mechanism by which LEC1 regulates nonembryonic development still remains elusive. In this study, we observed etiolation-related phenotypes in early seedlings of lec1 mutants and inducible LEC1 overexpression transgenic lines. Consistent with this, LEC1 promotes the expression of hypocotyl elongation-related genes in a darkness-dependent manner in spite of the comparable LEC1 transcript levels in the light- and dark-grown seedlings. Furthermore, we show that LEC1 interacts with PHYTOCHROME-INTERACTING FACTOR4 (PIF4), a major transcription modulator in postgermination development, to interdependently regulate hypocotyl elongation-related genes via direct binding to G-box element in the dark. Moreover, loss of LEC1 function suppresses the elongated hypocotyl phenotype of PIF-overaccumulating plants; conversely, inducible overexpression of LEC1 does not rescue the short hypocotyl in pif4 mutants. Our findings reveal that LEC1 acts as a coactivator of PIFs in transcriptional regulation during postembryonic growth, providing a possible mechanism by which plants fine-tune morphological development for their survival during the transition from the embryonic phase to seedling establishment.
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Mingkun
authors.initials: M
authors.lastname: Huang
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yilong
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Xu
authors.identifier: http://orcid.org/0000-0003-1970-0608
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China.
authors.forename: Yuge
authors.initials: Y
authors.lastname: Li
authors.affiliation: Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China houxl@scib.ac.cn.
authors.forename: Xingliang
authors.identifier: http://orcid.org/0000-0002-3964-2372
authors.initials: X
authors.lastname: Hou
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D022762:CCAAT-Enhancer-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D017343:Genes, Plant; D018546:Hypocotyl / Q000254:growth & development; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D011485:Protein Binding; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D022762:CCAAT-Enhancer-Binding Proteins; C113191:LEC1 protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis