title: Robust expression and association of ZmCCA1 with circadian rhythms in maize.
abstract: In plants, the circadian clock is an endogenous mechanism that controls a wide range of biological processes. To date, as one of the key world crops, little is known about the molecular mechanism and components of the circadian clock in maize (Zea mays). In this study, we characterized the CIRCADIAN CLOCK ASSOCIATED1 gene of maize (ZmCCA1), an ortholog of CCA1 in Arabidopsis thaliana (AtCCA1). Quantitative real-time PCR analysis revealed that ZmCCA1 was expressed in leaves and stem apex meristems in a rhythmic pattern under long day and short day conditions, and its peak gene expression appeared during the morning. ZmCCA1 transcripts accumulated in all tissues evaluated, with higher levels in tassels and ears. Additionally, the expression of another photoperiod gene ZmTOC1 peaked 12 h after dawn on long days and at 10 h after dawn on short days. Subcellular localization analysis revealed that the ZmCCA1 protein is directed to the cell nucleus. Overexpression of ZmCCA1 in Arabidopsis reduced the expression levels of downstream genes, including GIGANTEA (AtGI), CONSTANS (AtCO), and FLOWERING LOCUST (AtFT), and resulted in longer hypocotyls and delayed flowering. Taken together, our data suggest that ZmCCA1 may be a core component of the circadian clock in maize.
authors.affiliation: College of Agronomy, Henan Agricultural University, 95 Wenhua Road, Zhengzhou, China.
authors.forename: Xintao
authors.initials: X
authors.lastname: Wang
authors.forename: Liuji
authors.initials: L
authors.lastname: Wu
authors.forename: Shaofang
authors.initials: S
authors.lastname: Zhang
authors.forename: Liancheng
authors.initials: L
authors.lastname: Wu
authors.forename: Lixia
authors.initials: L
authors.lastname: Ku
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Wei
authors.forename: Lili
authors.initials: L
authors.lastname: Xie
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism; D002940:Circadian Rhythm; D017124:Conserved Sequence; D020224:Expressed Sequence Tags; D035264:Flowers / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008969:Molecular Sequence Data; D017440:Photoperiod; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D011993:Recombinant Fusion Proteins; D020539:Sequence Analysis, Protein; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic; D003313:Zea mays / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D010940:Plant Proteins; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors