Journal Article

Combined <i>in silico</i>/<i>in vivo</i> analysis of mechanisms providing for root apical meristem self-organization and maintenance

V. V. Mironova, N. A. Omelyanchuk, E. S. Novoselova, A. V. Doroshkov, F. V. Kazantsev, A. V. Kochetov, N. A. Kolchanov, E. Mjolsness and V. A. Likhoshvai

in Annals of Botany

Published on behalf of The Annals of Botany Company

Volume 110, issue 2, pages 349-360
Published in print July 2012 | ISSN: 0305-7364
Published online April 2012 | e-ISSN: 1095-8290 | DOI: http://dx.doi.org/10.1093/aob/mcs069

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  • Ecology and Conservation
  • Evolutionary Biology
  • Plant Sciences and Forestry

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Background and Aims

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.

Key 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.

Keywords: Auxin response; root apical meristem; patterning; reverse fountain; reflected flow; mathematical model; Arabidopsis thaliana

Journal Article.  8556 words.  Illustrated.

Subjects: Ecology and Conservation ; Evolutionary Biology ; Plant Sciences and Forestry

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