title: Whole-Transcriptome Analysis of Differentially Expressed Genes in the Vegetative Buds, Floral Buds and Buds of Chrysanthemum morifolium.
abstract: BACKGROUND
  Chrysanthemum morifolium is an important floral crop that is cultivated worldwide. However, due to a lack of genomic resources, very little information is available concerning the molecular mechanisms of flower development in chrysanthemum.
  
  
  RESULTS
  The transcriptomes of chrysanthemum vegetative buds, floral buds and buds were sequenced using Illumina paired-end sequencing technology. A total of 15.4 Gb of reads were assembled into 91,367 unigenes with an average length of 739 bp. A total of 43,137 unigenes showed similarity to known proteins in the Swissprot or NCBI non-redundant protein databases. Additionally, 25,424, 24,321 and 13,704 unigenes were assigned to 56 gene ontology (GO) categories, 25 EuKaryotic Orthologous Groups (KOG) categories, and 285 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, respectively. A total of 1,876 differentially expressed genes (DEGs) (1,516 up-regulated, 360 down-regulated) were identified between vegetative buds and floral buds, and 3,300 DEGs (1,277 up-regulated, 1,706 down-regulated) were identified between floral buds and buds. Many genes encoding important transcription factors (e.g., AP2, MYB, MYC, WRKY, NAC and CRT) as well as proteins involved in carbohydrate metabolism, protein kinase activity, plant hormone signal transduction, and the defense responses, among others, were considerably up-regulated in floral buds. Genes involved in the photoperiod pathway and flower organ determination were also identified. These genes represent important candidate genes for molecular cloning and functional analysis to study flowering regulation in chrysanthemum.
  
  
  CONCLUSIONS
  This comparative transcriptome analysis revealed significant differences in gene expression and signaling pathway components between the vegetative buds, floral buds and buds of Chrysanthemum morifolium. A wide range of genes was implicated in regulating the phase transition from vegetative to reproductive growth. These results should aid researchers in the study of flower-time regulation, breeding and molecular biology in chrysanthemum.
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Liu
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Dongliang
authors.initials: D
authors.lastname: Du
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Huitang
authors.initials: H
authors.lastname: Pan
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Tangren
authors.initials: T
authors.lastname: Cheng
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.affiliation: Beijing Key Laboratory of Ornamental Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and rural ecological environment, College of Landscape Architecture, Beijing Forestry University, Beijing, 100083, China.
authors.forename: Qixiang
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D031202:Chrysanthemum / Q000235:genetics* / Q000254:growth & development; D035264:Flowers / Q000235:genetics / Q000254:growth & development; D020869:Gene Expression Profiling / Q000379:methods*; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D058977:Molecular Sequence Annotation