[BITprogram] Today's 12:30 talk: "Auxin regulation of root patterning", Victoria Mironova

fletcher fletcher at ics.uci.edu
Thu Oct 1 10:09:03 PDT 2009

12:30pm Thursday October 1, Bren Hall 3011

Informal seminar of the ICS Center for Computational Morphodynamics:

"Auxin regulation of root patterning"

Victoria Mironova
Institute for Cytology and Genetics (ICG), Novosibirsk

Abstract: In many plants and plant tissues, the growth hormone auxin 
plays a critical role in patterning and morphogenesis. For example, 
auxin distribution along the central root axis of many plants has a 
maximum in the root apical meristem, where it regulates stem cell niche 
maintenance.  Additional auxin maxima occur in the basal meristem and at 
the shoot-root junction, where they trigger lateral and adventitious 
root initiation, respectively. We simulated auxin's activation and 
inhibition of its own active transport at low and high auxin levels, 
respectively, taking into account the known auxin regulation of 
transcription and degradation of PIN family auxin carriers.  Simulations 
showed that these regulatory interactions are sufficient for 
self-organization of the auxin distribution pattern along the central 
root axis. Additional maxima of auxin concentration in proximal root 
regions appeared in response to steadily increasing auxin flow from the 
growing shoot. The model predicts that the prevalence of lateral or 
adventitious roots in plant species, corresponding to two main types of 
plant root architecture (taproot or fibrous), may be based on different 
efficiencies with which auxin inhibits its own transport. The model was 
extended with rules for cell dynamics so that cell divisions were also 
governed by auxin along with another morphogen Y which combines the 
actions of cytokinin and ethylene on cell divisions in the root. The 
positional information specified by the gradients of two morphogens 
makes it possible to differentiate cell types, and explains root 
patterning along its central axis.

Joint work with Nadezda Omelyanchuk and other members of ICG Novosibirsk 
(Russia), and with members of UCI's Institute for Genomics and 
Bioinformatics (IGB) and Center for Complex Biological Systems (CCBS).

This is the first seminar of the new Center for Computational 
of the Donald Bren School of Information and Computer Sciences.

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