title: Arabidopsis homolog of trithorax1 (ATX1) is required for cell production, patterning, and morphogenesis in root development.
abstract: Arabidopsis homolog of trithorax1 (ATX1/SDG27), a known regulator of flower development, encodes a H3K4histone methyltransferase that maintains a number of genes in an active state. In this study, the role of ATX1 in root development was evaluated. The loss-of-function mutant atx1-1 was impaired in primary root growth. The data suggest that ATX1 controls root growth by regulating cell cycle duration, cell production, and the transition from cell proliferation in the root apical meristem (RAM) to cell elongation. In atx1-1, the quiescent centre (QC) cells were irregular in shape and more expanded than those of the wild type. This feature, together with the atypical distribution of T-divisions, the presence of oblique divisions, and the abnormal cell patterning in the RAM, suggests a lack of coordination between cell division and cell growth in the mutant. The expression domain of QC-specific markers was expanded both in the primary RAM and in the developing lateral root primordia of atx1-1 plants. These abnormalities were independent of auxin-response gradients. ATX1 was also found to be required for lateral root initiation, morphogenesis, and emergence. The time from lateral root initiation to emergence was significantly extended in the atx1-1 mutant. Overall, these data suggest that ATX1 is involved in the timing of root development, stem cell niche maintenance, and cell patterning during primary and lateral root development. Thus, ATX1 emerges as an important player in root system architecture.
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 510-3, 62250 Cuernavaca, Morelos, México.
authors.forename: Selene
authors.initials: S
authors.lastname: Napsucialy-Mendivil
authors.affiliation: Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados, Unidad Irapuato, Irapuato, Gto., CP 36821, México.
authors.forename: Raúl
authors.initials: R
authors.lastname: Alvarez-Venegas
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 510-3, 62250 Cuernavaca, Morelos, México.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Shishkova
authors.affiliation: Departamento de Biología Molecular de Plantas, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Apartado Postal 510-3, 62250 Cuernavaca, Morelos, México jdubrov@ibt.unam.mx.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Dubrovsky
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D019521:Body Patterning / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D011495:Histone-Lysine N-Methyltransferase; D007210:Indoleacetic Acids / Q000494:pharmacology; D018519:Meristem / Q000187:drug effects / Q000378:metabolism; D009154:Mutation; D018517:Plant Roots / Q000166:cytology* / Q000187:drug effects / Q000254:growth & development*; D055153:Stem Cell Niche / Q000187:drug effects; D013997:Time Factors; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D007210:Indoleacetic Acids; D014157:Transcription Factors; C504056:At2g31650 protein, Arabidopsis; D011495:Histone-Lysine N-Methyltransferase
keywords: Arabidopsis; lateral root development; patterning; root apical meristem; root development; root morphogenesis; root system.