title: MicroRNA396-Targeted SHORT VEGETATIVE PHASE Is Required to Repress Flowering and Is Related to the Development of Abnormal Flower Symptoms by the Phyllody Symptoms1 Effector.
abstract: Leafy flowers are the major symptoms of peanut witches' broom (PnWB) phytoplasma infection in Catharanthus roseus. The orthologs of the phyllody symptoms1 (PHYL1) effector of PnWB from other species of phytoplasma can trigger the proteasomal degradation of several MADS box transcription factors, resulting in leafy flower formation. In contrast, the flowering negative regulator gene SHORT VEGETATIVE PHASE (SVP) was up-regulated in PnWB-infected C. roseus plants, but most microRNA (miRNA) genes had repressed expression. Coincidentally, transgenic Arabidopsis (Arabidopsis thaliana) plants expressing the PHYL1 gene of PnWB (PHYL1 plants), which show leafy flower phenotypes, up-regulate SVP of Arabidopsis (AtSVP) but repress a putative regulatory miRNA of AtSVP, miR396. However, the mechanism by which PHYL1 regulates AtSVP and miR396 is unknown, and the evidence of miR396-mediated AtSVP degradation is lacking. Here, we show that miR396 triggers AtSVP messenger RNA (mRNA) decay using genetic approaches, a reporter assay, and high-throughput degradome profiles. Genetic evidence indicates that PHYL1 plants and atmir396a-1 mutants have higher AtSVP accumulation, whereas the transgenic plants overexpressing MIR396 display lower AtSVP expression. The reporter assay indicated that target-site mutation results in decreasing the miR396-mediated repression efficiency. Moreover, degradome profiles revealed that miR396 triggers AtSVP mRNA decay rather than miRNA-mediated cleavage, implying that AtSVP caused miR396-mediated translation inhibition. We hypothesize that PHYL1 directly or indirectly interferes with miR396-mediated AtSVP mRNA decay and synergizes with other effects (e.g. MADS box transcription factor degradation), resulting in abnormal flower formation. We anticipate our findings to be a starting point for studying the posttranscriptional regulation of PHYL1 effectors in symptom development.
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Chiao-Yin
authors.initials: CY
authors.lastname: Yang
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Yu-Hsin
authors.initials: YH
authors.lastname: Huang
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Chan-Pin
authors.identifier: http://orcid.org/0000-0002-9951-687X
authors.initials: CP
authors.lastname: Lin
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Yen-Yu
authors.initials: YY
authors.lastname: Lin
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Hao-Chun
authors.initials: HC
authors.lastname: Hsu
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Chun-Neng
authors.initials: CN
authors.lastname: Wang
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Li-Yu Daisy
authors.initials: LY
authors.lastname: Liu
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.).
authors.forename: Bing-Nan
authors.initials: BN
authors.lastname: Shen
authors.affiliation: Institute of Biotechnology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L., B.-N.S., S.-S.L.), Genome and Systems Biology Degree Program (S.-S.L.), Department of Plant Pathology and Microbiology (C.-Y.Y., Y.-H.H., C.-P.L., Y.-Y.L.), Institute of Ecology and Evolutionary Biology, Department of Life Science (H.-C.H., C.-N.W.), and Department of Agronomy (L.-Y.D.L.), National Taiwan University, Taipei 106, Taiwan; andAgricultural Biotechnology Research Center, Academia Sinica, Taipei 115, Taiwan (S.-S.L.) linss01@ntu.edu.tw.
authors.forename: Shih-Shun
authors.identifier: http://orcid.org/0000-0002-7295-5004
authors.initials: SS
authors.lastname: Lin
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D029681:Arabidopsis Proteins / Q000235:genetics*; D001483:Base Sequence; D030008:Catharanthus / Q000235:genetics / Q000382:microbiology; D035264:Flowers / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D035683:MicroRNAs / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D045582:Phytoplasma / Q000502:physiology; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D030821:Plants, Genetically Modified; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014157:Transcription Factors / Q000235:genetics*
chemical_list: D029681:Arabidopsis Proteins; C572930:MIRN396 microRNA, Arabidopsis; D035683:MicroRNAs; C407549:SVP protein, Arabidopsis; D014157:Transcription Factors