title: OsTIR1 and OsAFB2 downregulation via OsmiR393 overexpression leads to more tillers, early flowering and less tolerance to salt and drought in rice.
abstract: The microRNA miR393 has been shown to play a role in plant development and in the stress response by targeting mRNAs that code for the auxin receptors in Arabidopsis. In this study, we verified that two rice auxin receptor gene homologs (OsTIR1 and OsAFB2) could be targeted by OsmiR393 (Os for Oryza sativa). Two new phenotypes (increased tillers and early flowering) and two previously observed phenotypes (reduced tolerance to salt and drought and hyposensitivity to auxin) were observed in the OsmiR393-overexpressing rice plants. The OsmiR393-overexpressing rice demonstrated hyposensitivity to synthetic auxin-analog treatments. These data indicated that the phenotypes of OsmiR393-overexpressing rice may be caused through hyposensitivity to the auxin signal by reduced expression of two auxin receptor genes (OsTIR1 and OsAFB2). The expression of an auxin transporter (OsAUX1) and a tillering inhibitor (OsTB1) were downregulated by overexpression of OsmiR393, which suggested that a gene chain from OsmiR393 to rice tillering may be from OsTIR1 and OsAFB2 to OsAUX1, which affected the transportation of auxin, then to OsTB1, which finally controlled tillering. The positive phenotypes (increased tillers and early flowering) and negative phenotypes (reduced tolerance to salt and hyposensitivity to auxin) of OsmiR393-overexpressing rice present a dilemma for molecular breeding.
authors.affiliation: Key Laboratory of South China Agricultural Plant Genetics and Breeding, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Kuaifei
authors.initials: K
authors.lastname: Xia
authors.forename: Ren
authors.initials: R
authors.lastname: Wang
authors.forename: Xiaojin
authors.initials: X
authors.lastname: Ou
authors.forename: Zhongming
authors.initials: Z
authors.lastname: Fang
authors.forename: Changen
authors.initials: C
authors.lastname: Tian
authors.forename: Jun
authors.initials: J
authors.lastname: Duan
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Wang
authors.forename: Mingyong
authors.initials: M
authors.lastname: Zhang
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics*; D055864:Droughts; D035264:Flowers / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant / Q000235:genetics; D007210:Indoleacetic Acids / Q000378:metabolism; D035683:MicroRNAs / Q000235:genetics* / Q000378:metabolism; D008954:Models, Biological; D009280:Naphthaleneacetic Acids / Q000494:pharmacology; D009928:Organ Specificity / Q000187:drug effects / Q000235:genetics; D012275:Oryza / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D015203:Reproducibility of Results; D012689:Sequence Homology, Nucleic Acid; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D012965:Sodium Chloride / Q000494:pharmacology*; D013997:Time Factors
chemical_list: D007210:Indoleacetic Acids; D035683:MicroRNAs; D009280:Naphthaleneacetic Acids; D010940:Plant Proteins; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C046131:auxin receptor, plant; D015084:2,4-Dichlorophenoxyacetic Acid; C034182:1-naphthaleneacetic acid; D012965:Sodium Chloride