title: A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity.
abstract: Boron is an essential micronutrient for plants and is taken up in the form of boric acid (BA). Despite this, a high BA concentration is toxic for the plants, inhibiting root growth and is thus a significant problem in semi-arid areas in the world. In this work, we report the molecular basis for the inhibition of root growth caused by boron. We show that application of BA reduces the size of root meristems, correlating with the inhibition of root growth. The decrease in meristem size is caused by a reduction of cell division. Mitotic cell number significantly decreases and the expression level of key core cell cycle regulators is modulated. The modulation of the cell cycle does not appear to act through cytokinin and auxin signalling. A global expression analysis reveals that boron toxicity induces the expression of genes related with abscisic acid (ABA) signalling, ABA response and cell wall modifications, and represses genes that code for water transporters. These results suggest that boron toxicity produces a reduction of water and BA uptake, triggering a hydric stress response that produces root growth inhibition.
authors: Departamento Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors: Felipe
authors: F
authors: Aquea
authors: Fernan
authors: F
authors: Federici
authors: Cristian
authors: C
authors: Moscoso
authors: Andrea
authors: A
authors: Vega
authors: Pastor
authors: P
authors: Jullian
authors: Jim
authors: J
authors: Haseloff
authors: Patricio
authors: P
authors: Arce-Johnson
mesh_terms: D000040:Abscisic Acid / Q000235:genetics; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics; D001692:Biological Transport; D001888:Boric Acids / Q000378:metabolism / Q000494:pharmacology*; D001895:Boron / Q000633:toxicity*; D002473:Cell Wall / Q000378:metabolism; D003681:Dehydration; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000235:genetics*; D018519:Meristem / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D008938:Mitosis; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010937:Plant Growth Regulators / Q000235:genetics; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development / Q000502:physiology; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013312:Stress, Physiological / Q000502:physiology; D014867:Water / Q000502:physiology
chemical_list: D029681:Arabidopsis Proteins; D001888:Boric Acids; D010937:Plant Growth Regulators; D014867:Water; D000040:Abscisic Acid; D001895:Boron; C032688:boric acid