title: Crosstalk between cold response and flowering in Arabidopsis is mediated through the flowering-time gene SOC1 and its upstream negative regulator FLC.
abstract: The appropriate timing of flowering is pivotal for reproductive success in plants; thus, it is not surprising that flowering is regulated by complex genetic networks that are fine-tuned by endogenous signals and environmental cues. The Arabidopsis thaliana flowering-time gene SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1) encodes a MADS box transcription factor and is one of the key floral activators integrating multiple floral inductive pathways, namely, long-day, vernalization, autonomous, and gibberellin-dependent pathways. To elucidate the downstream targets of SOC1, microarray analyses were performed. The analysis revealed that the soc1-2 knockout mutant has increased, and an SOC1 overexpression line has decreased, expression of cold response genes such as CBFs (for CRT/DRE binding factors) and COR (for cold regulated) genes, suggesting that SOC1 negatively regulates the expression of the cold response genes. By contrast, overexpression of cold-inducible CBFs caused late flowering through increased expression of FLOWERING LOCUS C (FLC), an upstream negative regulator of SOC1. Our results demonstrate the presence of a feedback loop between cold response and flowering-time regulation; this loop delays flowering through the increase of FLC when a cold spell is transient as in fall or early spring but suppresses the cold response when floral induction occurs through the repression of cold-inducible genes by SOC1.
authors.affiliation: National Research Laboratory of Plant Developmental Genetics, School of Biological Sciences, Seoul National University, Seoul 151-742, Korea.
authors.forename: Eunjoo
authors.initials: E
authors.lastname: Seo
authors.forename: Horim
authors.initials: H
authors.lastname: Lee
authors.forename: Jin
authors.initials: J
authors.lastname: Jeon
authors.forename: Hanna
authors.initials: H
authors.lastname: Park
authors.forename: Jungmook
authors.initials: J
authors.lastname: Kim
authors.forename: Yoo-Sun
authors.initials: YS
authors.lastname: Noh
authors.forename: Ilha
authors.initials: I
authors.lastname: Lee
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D047369:Chromatin Immunoprecipitation; D003080:Cold Temperature; D035264:Flowers / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis
chemical_list: C419046:AGL20 protein, Arabidopsis; D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; D026161:MADS Domain Proteins