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Modelling and experimental analysis of hormonal crosstalk in Arabidopsis.

Liu J, Mehdi S, Topping J, Tarkowski P, Lindsey K - Mol. Syst. Biol. (2010)

Bottom Line: Modelling correctly predicts experimental results for the effect of the pls gene mutation on endogenous cytokinin concentration.Modelling further reveals that a bell-shaped dose-response relationship between endogenous auxin and root length is established via PLS.This combined modelling and experimental analysis provides new insights into the integration of hormonal signals in plants.

View Article: PubMed Central - PubMed

Affiliation: The Integrative Cell Biology Laboratory and The Biophysical Sciences Institute, School of Biological and Biomedical Sciences, Durham University, Durham, UK. junli.liu@durham.ac.uk

ABSTRACT
An important question in plant biology is how genes influence the crosstalk between hormones to regulate growth. In this study, we model POLARIS (PLS) gene function and crosstalk between auxin, ethylene and cytokinin in Arabidopsis. Experimental evidence suggests that PLS acts on or close to the ethylene receptor ETR1, and a mathematical model describing possible PLS-ethylene pathway interactions is developed, and used to make quantitative predictions about PLS-hormone interactions. Modelling correctly predicts experimental results for the effect of the pls gene mutation on endogenous cytokinin concentration. Modelling also reveals a role for PLS in auxin biosynthesis in addition to a role in auxin transport. The model reproduces available mutants, and with new experimental data provides new insights into how PLS regulates auxin concentration, by controlling the relative contribution of auxin transport and biosynthesis and by integrating auxin, ethylene and cytokinin signalling. Modelling further reveals that a bell-shaped dose-response relationship between endogenous auxin and root length is established via PLS. This combined modelling and experimental analysis provides new insights into the integration of hormonal signals in plants.

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Related in: MedlinePlus

Prediction of response of unknown molecule, X, to exogenous ACC (A) and auxin (B) shows response of X to exogenous ACC and auxin follows opposite trends.
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f8: Prediction of response of unknown molecule, X, to exogenous ACC (A) and auxin (B) shows response of X to exogenous ACC and auxin follows opposite trends.

Mentions: Although some components have been identified recently (Stepanova et al, 2008), the molecular basis for the interaction between the ethylene signalling response and the auxin response is not fully elucidated. A molecule or molecules, X, can be designated in the model as a module mediating the interaction. The model provides the opportunity to examine how the unknown molecule(s) X behave when exogenous auxin and ethylene concentrations change. Figure 8 shows that, when the exogenous ethylene concentration increases, the concentration of X initially increases rapidly, then approaches a constant value. However, when the exogenous auxin concentration increases, X initially decreases rapidly and then approaches a constant value. The trend analysis for X may be of use for searching for the candidate molecules that interact downstream of ethylene signalling to positively regulate the auxin response.


Modelling and experimental analysis of hormonal crosstalk in Arabidopsis.

Liu J, Mehdi S, Topping J, Tarkowski P, Lindsey K - Mol. Syst. Biol. (2010)

Prediction of response of unknown molecule, X, to exogenous ACC (A) and auxin (B) shows response of X to exogenous ACC and auxin follows opposite trends.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2913391&req=5

f8: Prediction of response of unknown molecule, X, to exogenous ACC (A) and auxin (B) shows response of X to exogenous ACC and auxin follows opposite trends.
Mentions: Although some components have been identified recently (Stepanova et al, 2008), the molecular basis for the interaction between the ethylene signalling response and the auxin response is not fully elucidated. A molecule or molecules, X, can be designated in the model as a module mediating the interaction. The model provides the opportunity to examine how the unknown molecule(s) X behave when exogenous auxin and ethylene concentrations change. Figure 8 shows that, when the exogenous ethylene concentration increases, the concentration of X initially increases rapidly, then approaches a constant value. However, when the exogenous auxin concentration increases, X initially decreases rapidly and then approaches a constant value. The trend analysis for X may be of use for searching for the candidate molecules that interact downstream of ethylene signalling to positively regulate the auxin response.

Bottom Line: Modelling correctly predicts experimental results for the effect of the pls gene mutation on endogenous cytokinin concentration.Modelling further reveals that a bell-shaped dose-response relationship between endogenous auxin and root length is established via PLS.This combined modelling and experimental analysis provides new insights into the integration of hormonal signals in plants.

View Article: PubMed Central - PubMed

Affiliation: The Integrative Cell Biology Laboratory and The Biophysical Sciences Institute, School of Biological and Biomedical Sciences, Durham University, Durham, UK. junli.liu@durham.ac.uk

ABSTRACT
An important question in plant biology is how genes influence the crosstalk between hormones to regulate growth. In this study, we model POLARIS (PLS) gene function and crosstalk between auxin, ethylene and cytokinin in Arabidopsis. Experimental evidence suggests that PLS acts on or close to the ethylene receptor ETR1, and a mathematical model describing possible PLS-ethylene pathway interactions is developed, and used to make quantitative predictions about PLS-hormone interactions. Modelling correctly predicts experimental results for the effect of the pls gene mutation on endogenous cytokinin concentration. Modelling also reveals a role for PLS in auxin biosynthesis in addition to a role in auxin transport. The model reproduces available mutants, and with new experimental data provides new insights into how PLS regulates auxin concentration, by controlling the relative contribution of auxin transport and biosynthesis and by integrating auxin, ethylene and cytokinin signalling. Modelling further reveals that a bell-shaped dose-response relationship between endogenous auxin and root length is established via PLS. This combined modelling and experimental analysis provides new insights into the integration of hormonal signals in plants.

Show MeSH
Related in: MedlinePlus