title: ARF2 coordinates with PLETHORAs and PINs to orchestrate ABA-mediated root meristem activity in Arabidopsis .
abstract: Multiple hormones, including abscisic acid (ABA) and auxin, regulate cell division and differentiation of Arabidopsis root meristems. AUXIN RESPONSE FACTOR 2 (ARF2) functions as a negative regulator of ABA responses, as seed germination and primary root growth of arf2 mutants are hypersensitive to ABA. In this study, we found that ABA treatment reduced the expression levels of the PIN-FORMEDs (PIN) auxin efflux carriers, PIN1, PIN3, PIN4, and PIN7, to a greater extent in the root meristems of arf2-101 mutant than in the wild type. Also, arf2-101 pin1 and arf2-101 pin4 double mutants show less ABA-induced inhibition of root meristem activity than the arf2-101 mutants. Furthermore, ARF2 positively mediates the transcripts of transcription factor PLETHORA 1 (PLT1) gene but negatively mediates PLT2 at protein level in root meristems. Using a dexamethasone (DEX)-inducible transgenic line, Pro35S:PLT2-GR, we showed that PLT2 greatly promotes cell division and completely inhibits cell differentiation in root meristems of the arf2-101 mutant once PLT2 is induced by DEX, which can be partially reversed by ABA treatment, suggesting that ABA regulates root meristem activity in both ARF2-dependent and independent pathways. Our results uncover a complex regulatory architecture in which ARF2 coordinates with PLTs and PINs to orchestrate ABA-mediated regulation of root meristem activity in Arabidopsis.
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Sujittra
authors.initials: S
authors.lastname: Promchuea
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Yujuan
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing 100193, China.|National Center for Plant Gene Research, Beijing 100193, China.
authors.forename: Zhizhong
authors.initials: Z
authors.lastname: Gong
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology*; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D012097:Repressor Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: C503421:ARF2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D012097:Repressor Proteins; D049452:Green Fluorescent Proteins; D000040:Abscisic Acid
keywords:  auxin; AUXIN RESPONSE FACTOR; Abscisic acid; Arabidopsis; PIN-FORMED; PLETHORA; root meristem