title: Histone acetylation accompanied with promoter sequences displaying differential expression profiles of B-class MADS-box genes for phalaenopsis floral morphogenesis.
abstract: Five B-class MADS-box genes, including four APETALA3 (AP3)-like PeMADS2∼5 and one PISTILLATA (PI)-like PeMADS6, specify the spectacular flower morphology in orchids. The PI-like PeMADS6 ubiquitously expresses in all floral organs. The four AP3-like genes, resulted from two duplication events, express ubiquitously at floral primordia and early floral organ stages, but show distinct expression profiles at late floral organ primordia and floral bud stages. Here, we isolated the upstream sequences of PeMADS2∼6 and studied the regulatory mechanism for their distinct gene expression. Phylogenetic footprinting analysis of the 1.3-kb upstream sequences of AP3-like PeMADS2∼5 showed that their promoter regions have sufficiently diverged and contributed to their subfunctionalization. The amplified promoter sequences of PeMADS2∼6 could drive beta-glucuronidase (GUS) gene expression in all floral organs, similar to their expression at the floral primordia stage. The promoter sequence of PeMADS4, exclusively expressed in lip and column, showed a 1.6∼3-fold higher expression in lip/column than in sepal/petal. Furthermore, we noted a 4.9-fold increase in histone acetylation (H3K9K14ac) in the translation start region of PeMADS4 in lip as compared in petal. All these results suggest that the regulation via the upstream sequences and increased H3K9K14ac level may act synergistically to display distinct expression profiles of the AP3-like genes at late floral organ primordia stage for Phalaenopsis floral morphogenesis.
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Chia-Chi
authors.initials: CC
authors.lastname: Hsu
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Pei-Shan
authors.initials: PS
authors.lastname: Wu
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Tien-Chih
authors.initials: TC
authors.lastname: Chen
authors.affiliation: Institute of Plant Biology, National Taiwan University, Taipei, Taiwan.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Yu
authors.affiliation: Institute of Tropic Plant Sciences, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Wen-Chieh
authors.initials: WC
authors.lastname: Tsai
authors.affiliation: Institute of Plant Biology, National Taiwan University, Taipei, Taiwan.
authors.forename: Keqiang
authors.initials: K
authors.lastname: Wu
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Wen-Luan
authors.initials: WL
authors.lastname: Wu
authors.affiliation: Orchid Research Center, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Wen-Huei
authors.initials: WH
authors.lastname: Chen
authors.affiliation: Department of Life Sciences, National Cheng Kung University, Tainan, Taiwan; Orchid Research Center, National Cheng Kung University, Tainan, Taiwan.
authors.forename: Hong-Hwa
authors.initials: HH
authors.lastname: Chen
mesh_terms: D000107:Acetylation; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017124:Conserved Sequence; D019175:DNA Methylation; D035264:Flowers / Q000235:genetics / Q000254:growth & development*; D020869:Gene Expression Profiling; D005966:Glucuronidase / Q000235:genetics; D006657:Histones / Q000378:metabolism*; D007438:Introns / Q000235:genetics; D026161:MADS Domain Proteins / Q000235:genetics*; D009024:Morphogenesis; D059372:Nucleotide Motifs; D029595:Orchidaceae / Q000235:genetics* / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics*
chemical_list: D006657:Histones; D026161:MADS Domain Proteins; D010940:Plant Proteins; D005966:Glucuronidase