title: Flower development of Phalaenopsis orchid involves functionally divergent SEPALLATA-like genes.
abstract: The Phalaenopsis orchid produces complex flowers that are commercially valuable, which has promoted the study of its flower development. E-class MADS-box genes, SEPALLATA (SEP), combined with B-, C- and D-class MADS-box genes, are involved in various aspects of plant development, such as floral meristem determination, organ identity, fruit maturation, seed formation and plant architecture. Four SEP-like genes were cloned from Phalaenopsis orchid, and the duplicated PeSEPs were grouped into PeSEP1/3 and PeSEP2/4. All PeSEPs were expressed in all floral organs. PeSEP2 expression was detectable in vegetative tissues. The study of protein-protein interactions suggested that PeSEPs may form higher order complexes with the B-, C-, D-class and AGAMOUS LIKE6-related MADS-box proteins to determine floral organ identity. The tepal became a leaf-like organ when PeSEP3 was silenced by virus-induced silencing, with alterations in epidermis identity and contents of anthocyanin and chlorophyll. Silencing of PeSEP2 had minor effects on the floral phenotype. Silencing of the E-class genes PeSEP2 and PeSEP3 resulted in the downregulation of B-class PeMADS2-6 genes, which indicates an association of PeSEP functions and B-class gene expression. These findings reveal the important roles of PeSEP in Phalaenopsis floral organ formation throughout the developmental process by the formation of various multiple protein complexes.
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.
authors.forename: Zhao-Jun
authors.initials: ZJ
authors.lastname: Pan
authors.affiliation: Institute of Tropical Plant Sciences, National Cheng Kung University, Tainan, 701, Taiwan.
authors.forename: You-Yi
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.
authors.forename: Jian-Syun
authors.initials: JS
authors.lastname: Du
authors.affiliation: Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, 106, Taiwan.
authors.forename: Yun-Yu
authors.initials: YY
authors.lastname: Chen
authors.affiliation: Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 115, Taiwan.
authors.forename: Mei-Chu
authors.initials: MC
authors.lastname: Chung
authors.affiliation: Institute of Tropical Plant Sciences, National Cheng Kung University, Tainan, 701, Taiwan.|Orchid Research Center, National Cheng Kung University, Tainan, 701, Taiwan.
authors.forename: Wen-Chieh
authors.initials: WC
authors.lastname: Tsai
authors.affiliation: Institute of Ecology and Evolutionary Biology, National Taiwan University, Taipei, 106, Taiwan.
authors.forename: Chun-Neng
authors.initials: CN
authors.lastname: Wang
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, 701, Taiwan.|Orchid Research Center, National Cheng Kung University, Tainan, 701, Taiwan.
authors.forename: Hong-Hwa
authors.initials: HH
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D048430:Cell Shape / Q000235:genetics; D003001:Cloning, Molecular; D035264:Flowers / Q000235:genetics* / Q000254:growth & development* / Q000648:ultrastructure; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D053263:Gene Regulatory Networks; D020868:Gene Silencing; D017343:Genes, Plant; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D029595:Orchidaceae / Q000235:genetics* / Q000254:growth & development*; D009928:Organ Specificity / Q000235:genetics; D038081:Organogenesis / Q000235:genetics; D010641:Phenotype; D010802:Phylogeny; D019441:Plant Epidermis / Q000166:cytology / Q000648:ultrastructure; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic / Q000235:genetics; D011485:Protein Binding
chemical_list: D026161:MADS Domain Proteins; D010940:Plant Proteins
keywords: Phalaenopsis; SEPALLATA; complex formation; divergence; flower development; orchid