title: Overexpression of Arabidopsis miR157b induces bushy architecture and delayed phase transition in Torenia fournieri.
abstract: miR156/157 is a small RNA molecule that is highly conserved among various plant species. Overexpression of miR156/157 has been reported to induce bushy architecture and delayed phase transition in several plant species. To investigate the effect of miR157 overexpression in a horticultural plant, and to explore the applicability of miRNA to molecular breeding, we introduced Arabidopsis                 MIR157b (AtMIR157b) into torenia (Torenia fournieri). The resulting 35S:AtMIR157b plants showed a high degree of branching along with small leaves, which resembled miR156/157-overexpressing plants of other species. We also isolated torenia SBP-box genes with target miR156/157 sequences and confirmed that their expression was selectively downregulated in 35S:AtMIR157b plants. The reduced accumulation of mRNA was probably due to sequence specificity. Moreover, expression of torenia homologs of the SBP-box protein-regulated genes TfLFY and TfMIR172 was also reduced by AtmiR157 overexpression. These findings suggest that the molecular mechanisms of miR156/157 regulation are conserved between Arabidopsis and torenia. The bushy architecture and small leaves of 35S:AtMIR157b torenia plants could be applied in molecular breeding of various horticultural plants as well as for increasing biomass and crop production.
authors.affiliation: National Institute of Floricultural Science, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8519, Japan. mshikata@affrc.go.jp
authors.forename: Masahito
authors.initials: M
authors.lastname: Shikata
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Yamaguchi
authors.forename: Katsutomo
authors.initials: K
authors.lastname: Sasaki
authors.forename: Norihiro
authors.initials: N
authors.lastname: Ohtsubo
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015870:Gene Expression; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics*; D019684:Magnoliopsida / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; C583246:MIRN157 microRNA, Arabidopsis; D035683:MicroRNAs; D010940:Plant Proteins; D012333:RNA, Messenger; D018749:RNA, Plant; D014157:Transcription Factors