title: A putative CCAAT-binding transcription factor is a regulator of flowering timing in Arabidopsis.
abstract: Flowering at the appropriate time of year is essential for successful reproduction in plants. We found that HAP3b in Arabidopsis (Arabidopsis thaliana), a putative CCAAT-binding transcription factor gene, is involved in controlling flowering time. Overexpression of HAP3b promotes early flowering while hap3b, a null mutant of HAP3b, is delayed in flowering under a long-day photoperiod. Under short-day conditions, however, hap3b did not show a delayed flowering compared to wild type based on the leaf number, suggesting that HAP3b may normally be involved in the photoperiod-regulated flowering pathway. Mutant hap3b plants showed earlier flowering upon gibberellic acid or vernalization treatment, which means that HAP3b is not involved in flowering promoted by gibberellin or vernalization. Further transcript profiling and gene expression analysis suggests that HAP3b can promote flowering by enhancing expression of key flowering time genes such as FLOWERING LOCUS T and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1. Our results provide strong evidence supporting a role of HAP3b in regulating flowering in plants grown under long-day conditions.
authors.affiliation: Department of Plants, Soils, and Climate, Utah State University, Logan, UT 84322, USA.
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Cai
authors.forename: Jenny
authors.initials: J
authors.lastname: Ballif
authors.forename: Saori
authors.initials: S
authors.lastname: Endo
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Davis
authors.forename: Mingxiang
authors.initials: M
authors.lastname: Liang
authors.forename: Dong
authors.initials: D
authors.lastname: Chen
authors.forename: Daryll
authors.initials: D
authors.lastname: DeWald
authors.forename: Joel
authors.initials: J
authors.lastname: Kreps
authors.forename: Tong
authors.initials: T
authors.lastname: Zhu
authors.forename: Yajun
authors.initials: Y
authors.lastname: Wu
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology*; D023081:CCAAT-Binding Factor / Q000502:physiology*; D035264:Flowers / Q000502:physiology*; D020869:Gene Expression Profiling; D005875:Gibberellins / Q000502:physiology; D016254:Mutagenesis, Insertional; D020411:Oligonucleotide Array Sequence Analysis; D017440:Photoperiod; D013997:Time Factors
chemical_list: D029681:Arabidopsis Proteins; D023081:CCAAT-Binding Factor; D005875:Gibberellins; C525376:HAP3b protein, Arabidopsis; C007842:gibberellic acid