title: Auxin modulates the transition from the mitotic cycle to the endocycle in Arabidopsis.
abstract: Amplification of genomic DNA by endoreduplication often marks the initiation of cell differentiation in animals and plants. The transition from mitotic cycles to endocycles should be developmentally programmed but how this process is regulated remains largely unknown. We show that the plant growth regulator auxin modulates the switch from mitotic cycles to endocycles in Arabidopsis; high levels of TIR1-AUX/IAA-ARF-dependent auxin signalling are required to repress endocycles, thus maintaining cells in mitotic cycles. By contrast, lower levels of TIR1-AUX/IAA-ARF-dependent auxin signalling trigger an exit from mitotic cycles and an entry into endocycles. Our data further demonstrate that this auxin-mediated modulation of the mitotic-to-endocycle switch is tightly coupled with the developmental transition from cell proliferation to cell differentiation in the Arabidopsis root meristem. The transient reduction of auxin signalling by an auxin antagonist PEO-IAA rapidly downregulates the expression of several core cell cycle genes, and we show that overexpressing one of the genes, CYCLIN A2;3 (CYCA2;3), partially suppresses an early initiation of cell differentiation induced by PEO-IAA. Taken together, these results suggest that auxin-mediated mitotic-to-endocycle transition might be part of the developmental programmes that balance cell proliferation and cell differentiation in the Arabidopsis root meristem.
authors.affiliation: RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa 230-0045, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ishida
authors.forename: Sumiko
authors.initials: S
authors.lastname: Adachi
authors.forename: Mika
authors.initials: M
authors.lastname: Yoshimura
authors.forename: Kohei
authors.initials: K
authors.lastname: Shimizu
authors.forename: Masaaki
authors.initials: M
authors.lastname: Umeda
authors.forename: Keiko
authors.initials: K
authors.lastname: Sugimoto
mesh_terms: D017360:Arabidopsis / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D019925:Cyclin A / Q000235:genetics / Q000502:physiology; D056751:Cyclin A2; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D044783:F-Box Proteins / Q000235:genetics / Q000502:physiology; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D007210:Indoleacetic Acids / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000378:metabolism; D010105:Oxygenases / Q000235:genetics / Q000502:physiology; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism; D018520:Plant Shoots / Q000166:cytology / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000166:cytology / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D011003:Ploidies; D011956:Receptors, Cell Surface / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D018797:Cell Cycle Proteins; D019925:Cyclin A; D056751:Cyclin A2; D004268:DNA-Binding Proteins; D044783:F-Box Proteins; D007210:Indoleacetic Acids; C111371:MONOPTEROS protein, Arabidopsis; D010937:Plant Growth Regulators; D011956:Receptors, Cell Surface; C501405:TIR1 protein, Arabidopsis; D014157:Transcription Factors; C543427:cyclin A2;3 protein, Arabidopsis; D010105:Oxygenases; C422746:YUC protein, Arabidopsis