title: Combined in silico/in vivo analysis of mechanisms providing for root apical meristem self-organization and maintenance.
abstract: OBJECTIVE
  The root apical meristem (RAM) is the plant stem cell niche which provides for the formation and continuous development of the root. Auxin is the main regulator of RAM functioning, and auxin maxima coincide with the sites of RAM initiation and maintenance. Auxin gradients are formed due to local auxin biosynthesis and polar auxin transport. The PIN family of auxin transporters plays a critical role in polar auxin transport, and two mechanisms of auxin maximum formation in the RAM based on PIN-mediated auxin transport have been proposed to date: the reverse fountain and the reflected flow mechanisms.
  
  
  METHODS
  The two mechanisms are combined here in in silico studies of auxin distribution in intact roots and roots cut into two pieces in the proximal meristem region. In parallel, corresponding experiments were performed in vivo using DR5::GFP Arabidopsis plants.
  
  
  RESULTS
  The reverse fountain and the reflected flow mechanism naturally cooperate for RAM patterning and maintenance in intact root. Regeneration of the RAM in decapitated roots is provided by the reflected flow mechanism. In the excised root tips local auxin biosynthesis either alone or in cooperation with the reverse fountain enables RAM maintenance.
  
  
  CONCLUSIONS
  The efficiency of a dual-mechanism model in guiding biological experiments on RAM regeneration and maintenance is demonstrated. The model also allows estimation of the concentrations of auxin and PINs in root cells during development and under various treatments. The dual-mechanism model proposed here can be a powerful tool for the study of several different aspects of auxin function in root.
authors.affiliation: Institute of Cytology and Genetics, SB RAS, Novosibirsk, Russia. kviki@bionet.nsc.ru
authors.forename: V V
authors.initials: VV
authors.lastname: Mironova
authors.forename: N A
authors.initials: NA
authors.lastname: Omelyanchuk
authors.forename: E S
authors.initials: ES
authors.lastname: Novoselova
authors.forename: A V
authors.initials: AV
authors.lastname: Doroshkov
authors.forename: F V
authors.initials: FV
authors.lastname: Kazantsev
authors.forename: A V
authors.initials: AV
authors.lastname: Kochetov
authors.forename: N A
authors.initials: NA
authors.lastname: Kolchanov
authors.forename: E
authors.initials: E
authors.lastname: Mjolsness
authors.forename: V A
authors.initials: VA
authors.lastname: Likhoshvai
mesh_terms: D017360:Arabidopsis / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D001692:Biological Transport; D003198:Computer Simulation; D007210:Indoleacetic Acids / Q000378:metabolism*; D018519:Meristem / Q000166:cytology / Q000254:growth & development* / Q000378:metabolism*; D008954:Models, Biological
chemical_list: D007210:Indoleacetic Acids