title: Regulation of miR399f transcription by AtMYB2 affects phosphate starvation responses in Arabidopsis.
abstract: Although a role for microRNA399 (miR399) in plant responses to phosphate (Pi) starvation has been indicated, the regulatory mechanism underlying miR399 gene expression is not clear. Here, we report that AtMYB2 functions as a direct transcriptional activator for miR399 in Arabidopsis (Arabidopsis thaliana) Pi starvation signaling. Compared with untransformed control plants, transgenic plants constitutively overexpressing AtMYB2 showed increased miR399f expression and tissue Pi contents under high Pi growth and exhibited elevated expression of a subset of Pi starvation-induced genes. Pi starvation-induced root architectural changes were more exaggerated in AtMYB2-overexpressing transgenic plants compared with the wild type. AtMYB2 directly binds to a MYB-binding site in the miR399f promoter in vitro, as well as in vivo, and stimulates miR399f promoter activity in Arabidopsis protoplasts. Transcription of AtMYB2 itself is induced in response to Pi deficiency, and the tissue expression patterns of miR399f and AtMYB2 are similar. Both genes are expressed mainly in vascular tissues of cotyledons and in roots. Our results suggest that AtMYB2 regulates plant responses to Pi starvation by regulating the expression of the miR399 gene.
authors.affiliation: Division of Applied Life Science-BK21 Program, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 660-701, Korea.
authors.forename: Dongwon
authors.initials: D
authors.lastname: Baek
authors.forename: Min Chul
authors.initials: MC
authors.lastname: Kim
authors.forename: Hyun Jin
authors.initials: HJ
authors.lastname: Chun
authors.forename: Songhwa
authors.initials: S
authors.lastname: Kang
authors.forename: Hyeong Cheol
authors.initials: HC
authors.lastname: Park
authors.forename: Gilok
authors.initials: G
authors.lastname: Shin
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Park
authors.forename: Mingzhe
authors.initials: M
authors.lastname: Shen
authors.forename: Hyewon
authors.initials: H
authors.lastname: Hong
authors.forename: Woe-Yeon
authors.initials: WY
authors.lastname: Kim
authors.forename: Doh Hoon
authors.initials: DH
authors.lastname: Kim
authors.forename: Sang Yeol
authors.initials: SY
authors.lastname: Lee
authors.forename: Ray A
authors.initials: RA
authors.lastname: Bressan
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Bohnert
authors.forename: Dae-Jin
authors.initials: DJ
authors.lastname: Yun
mesh_terms: D016960:Agrobacterium tumefaciens / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D047369:Chromatin Immunoprecipitation; D018548:Cotyledon / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D010710:Phosphates / Q000378:metabolism* / Q000494:pharmacology; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism; D017680:Potassium Compounds / Q000378:metabolism* / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011523:Protoplasts / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D012045:Regulatory Sequences, Nucleic Acid; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: D029681:Arabidopsis Proteins; C104175:MYB2 protein, Arabidopsis; D035683:MicroRNAs; D010710:Phosphates; D017680:Potassium Compounds; D018749:RNA, Plant; D015534:Trans-Activators; C013216:potassium phosphate