BIOMD0000000414
type: SBMLModel
parameter: 149652
name: Band2012_DII-Venus_ReducedModel
reaction: 149639
reaction: 149642
volume units: volume
time units: time
parameter: 149648
is described by: http://identifiers.org/pubmed/22393022
occurs in: http://identifiers.org/taxonomy/3701
parameter: 149651
compartment: 149636
curated: true
area units: area
is: MODEL1203230001
length unit: length
creator:
  ORG:
    orgname: Centre for Plant Integrative Biology, University of Nottingham
  n:
    given: Leah
    family: Band
modified:
  W3 CDTF: Fri May 18 11:30:23 BST 2012
parameter: 149650
substance units: substance
species: 149637
reaction: 149640
created:
  W3 CDTF: Thu Apr 05 15:39:10 BST 2012
notes: This model is from the article: Root gravitropism is regulated by a transient lateral auxin gradient controlled by a tipping-point mechanism. Band LR, Wells DM, Larrieu A, Sun J, Middleton AM, French AP, Brunoud G, Sato EM, Wilson MH, Péret B, Oliva M, Swarup R, Sairanen I, Parry G, Ljung K, Beeckman T, Garibaldi JM, Estelle M, Owen MR, Vissenberg K, Hodgman TC, Pridmore TP, King JR, Vernoux T, Bennett MJ. Proc Natl Acad Sci U S A. 2012 Mar 20;109(12):4668-73 22393022 , Abstract: Gravity profoundly influences plant growth and development. Plants respond to changes in orientation by using gravitropic responses to modify their growth. Cholodny and Went hypothesized over 80 years ago that plants bend in response to a gravity stimulus by generating a lateral gradient of a growth regulator at an organ's apex, later found to be auxin. Auxin regulates root growth by targeting Aux/IAA repressor proteins for degradation. We used an Aux/IAA-based reporter, domain II (DII)-VENUS, in conjunction with a mathematical model to quantify auxin redistribution following a gravity stimulus. Our multidisciplinary approach revealed that auxin is rapidly redistributed to the lower side of the root within minutes of a 90° gravity stimulus. Unexpectedly, auxin asymmetry was rapidly lost as bending root tips reached an angle of 40° to the horizontal. We hypothesize roots use a "tipping point" mechanism that operates to reverse the asymmetric auxin flow at the midpoint of root bending. These mechanistic insights illustrate the scientific value of developing quantitative reporters such as DII-VENUS in conjunction with parameterized mathematical models to provide high-resolution kinetics of hormone redistribution. This model corresponds to the simplified model described in the article. It is assumed that, on the timescale of DII-VENUS degradation, the concentrations of auxin, TIR1/AFB, and their complexes can be approximated by quasi-steady-state expressions. This reduced the full model to a si…
is version of: GO:0090354
creator:
  ORG:
    orgname: EMBL-EBI
  n:
    given: Vijayalakshmi
    family: Chelliah

149652
type: Parameter
constant: true
value: 0.16

149639
type: Reaction
kinetic law: 669978
product: 669966
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is: SBO:0000393
fast: false
reversible: false

669966
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stoichiometry: 1.0
species: 149637

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is: SBO:0000297
initial amount: NaN
in compartment: 149636
has only substance units: false
has part: Q940U6
has part: Q9XFM0
constant: false
boundary condition: false
initial concentration: 1.0

149636
type: Compartment
is version of: GO:0005623
is: SBO:0000290
constant: true
size: 1.0
spatial dimensions: 3.0

149642
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kinetic law: 670026
reactant: 670014
is version of: GO:0030163
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fast: false
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670014
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species: 149637

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type: Parameter
constant: true
value: 0.056

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constant: true
value: 0.52

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constant: true
value: 0.0053

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kinetic law: 670002
reactant: 669990
is version of: GO:0030163
is: SBO:0000179
fast: false
reversible: false

669990
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stoichiometry: 1.0
species: 149637