title: Identification and Characterization ofCYC-Like Genes in Regulation of Ray Floret Development inChrysanthemum morifolium.
abstract: Chrysanthemum morifolium, one of the most economically important ornamental crops worldwide, is well-known for the elaborate and complex inflorescence which is composed of both bilaterally symmetrical ray florets and radially symmetrical disc florets. Despite continuing efforts, the molecular mechanisms underlying regulation of the two flower types are still unclear so far.CYC-like proteins have been shown to control flower symmetry or regulate flower-type identity in several angiosperm plant lineages. In this study, we conducted comparative analysis of theCmCYC2genes in two chrysanthemum cultivars and their F1 progenies with various whorls of ray florets. SixCmCYCgenes were identified and sequenced, all of which were grouped into the CYC2 subclade. All the sixCmCYC2genes were predominantly expressed in reproductive organs, and in particular in the petal of ray florets. Of these genes, the transcription level ofCmCYC2cwas highly up-regulated in ray florets of the double-ray flowered heads. In addition, the result thatCmCYC2cwas highly expressed at key developing stages indicates its role in regulating petal development. Furthermore, overexpression ofCmCYC2cinC. lavandulifolium, one of the original species ofC. morifolium, led to significant increase in flower numbers and petal ligule length of ray florets. BesidesCmCYC2c, the expression ofCmCYC2fwas also significantly up-regulated in transgenic lines, implying a possible role in regulating development of ray florets. Both results of expression patterns and transgenic phenotypes suggest thatCmCYC2cis involved in regulating ray floret identity in the chrysanthemum. This study will be useful for genetic manipulation of flower shape in chrysanthemum and hence promote the process of molecular breeding.
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Di
authors.initials: D
authors.lastname: Huang
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Xiaowei
authors.initials: X
authors.lastname: Li
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Tengxun
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Huitang
authors.initials: H
authors.lastname: Pan
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Tangren
authors.initials: T
authors.lastname: Cheng
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University Beijing, China.
authors.forename: Qixiang
authors.initials: Q
authors.lastname: Zhang
keywords: CYCLOIDEA; Chrysanthemum morifolium; TCP; flower development; flower symmetry; inflorescence