title: A companion cell-dominant and developmentally regulated H3K4 demethylase controls flowering time in Arabidopsis via the repression of FLC expression.
abstract: Flowering time relies on the integration of intrinsic developmental cues and environmental signals. FLC and its downstream target FT are key players in the floral transition in Arabidopsis. Here, we characterized the expression pattern and function of JMJ18, a novel JmjC domain-containing histone H3K4 demethylase gene in Arabidopsis. JMJ18 was dominantly expressed in companion cells; its temporal expression pattern was negatively and positively correlated with that of FLC and FT, respectively, during vegetative development. Mutations in JMJ18 resulted in a weak late-flowering phenotype, while JMJ18 overexpressors exhibited an obvious early-flowering phenotype. JMJ18 displayed demethylase activity toward H3K4me3 and H3K4me2, and bound FLC chromatin directly. The levels of H3K4me3 and H3K4me2 in chromatins of FLC clade genes and the expression of FLC clade genes were reduced, whereas FT expression was induced and the protein expression of FT increased in JMJ18 overexpressor lines. The early-flowering phenotype caused by the overexpression of JMJ18 was mainly dependent on the functional FT. Our findings suggest that the companion cell-dominant and developmentally regulated JMJ18 binds directly to the FLC locus, reducing the level of H3K4 methylation in FLC chromatin and repressing the expression of FLC, thereby promoting the expression of FT in companion cells to stimulate flowering.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, China.
authors.forename: Hongchun
authors.initials: H
authors.lastname: Yang
authors.forename: Zhifu
authors.initials: Z
authors.lastname: Han
authors.forename: Ying
authors.initials: Y
authors.lastname: Cao
authors.forename: Di
authors.initials: D
authors.lastname: Fan
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Huixian
authors.initials: H
authors.lastname: Mo
authors.forename: Yi
authors.initials: Y
authors.lastname: Feng
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Zheng
authors.initials: Z
authors.lastname: Wang
authors.forename: Yanling
authors.initials: Y
authors.lastname: Yue
authors.forename: Sujuan
authors.initials: S
authors.lastname: Cui
authors.forename: She
authors.initials: S
authors.lastname: Chen
authors.forename: Jijie
authors.initials: J
authors.lastname: Chai
authors.forename: Ligeng
authors.initials: L
authors.lastname: Ma
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D002843:Chromatin / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D018506:Gene Expression Regulation, Plant; D006657:Histones / Q000235:genetics / Q000378:metabolism; D056484:Jumonji Domain-Containing Histone Demethylases / Q000235:genetics* / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics*; D008745:Methylation; D009154:Mutation; D010641:Phenotype
chemical_list: D029681:Arabidopsis Proteins; D002843:Chromatin; C418902:At5g10140 protein, Arabidopsis; C418905:FT protein, Arabidopsis; D006657:Histones; D026161:MADS Domain Proteins; D056484:Jumonji Domain-Containing Histone Demethylases