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Hormonal crosstalk for root development: a combined experimental and modeling perspective.

Liu J, Rowe J, Lindsey K - Front Plant Sci (2014)

Bottom Line: Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in developmental biology.Although a localized auxin concentration maximum in the root tip is important for root development, auxin concentration cannot change independently of multiple interacting hormones and genes.Moreover, we discuss that experimental evidence showing that, in root development, hormones and the associated regulatory and target genes form a network, in which relevant genes regulate hormone activities and hormones regulate gene expression.

View Article: PubMed Central - PubMed

Affiliation: The Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, The Biophysical Sciences Institute, Durham University Durham, UK.

ABSTRACT
Plants are sessile organisms and therefore they must adapt their growth and architecture to a changing environment. Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in developmental biology. Although a localized auxin concentration maximum in the root tip is important for root development, auxin concentration cannot change independently of multiple interacting hormones and genes. In this review, we discuss the experimental evidence showing that the POLARIS peptide of Arabidopsis plays an important role in hormonal crosstalk and root growth, and review the crosstalk between auxin and other hormones for root growth with and without osmotic stress. Moreover, we discuss that experimental evidence showing that, in root development, hormones and the associated regulatory and target genes form a network, in which relevant genes regulate hormone activities and hormones regulate gene expression. We further discuss how it is increasingly evident that mathematical modeling is a valuable tool for studying hormonal crosstalk. Therefore, a combined experimental and modeling study on hormonal crosstalk is important for elucidating the complexity of root development.

No MeSH data available.


Related in: MedlinePlus

A hormonal crosstalk network of auxin, ethylene and cytokinin for root development, showing that change in one signaling component leads to change in other signaling components in the network (modified with permission from Liu et al., 2013). The reaction rates are: v1, total auxin influx from all neighboring; v2, auxin biosynthesis rate in the cell; v3, total auxin efflux from the cell; v4, rate for conversion of the inactive form of the auxin receptor, Ra, to its active form, Ra*; v5, rate for conversion of the active form of the auxin receptor, Ra*, to its inactive form, Ra; v6, transcription rate of the POLARIS (PLS)gene; v7, decay rate of PLS mRNA; v8, translation rate of the PLS protein; v9, decay rate of PLS protein; v10, rate for conversion of the inactive form of the ethylene receptor, Re, to its active form by PLS protein (PLSp), Re*; v11, rate for conversion of the active form of ethylene receptor, Re*, to its inactive form, Re; v12, ethylene biosynthesis rate; v13, rate for removal of ethylene; v14, rate for conversion of the inactive form of the CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) protein, CTR1, to its active form, CTR1*; v15, rate for conversion of the active form of CTR1 protein, CTR1*, to its inactive form, CTR1; v16, rate for activation of the ethylene signaling response; v17, rate for removal of the unknown ethylene signaling component, X; v18, rate for cytokinin biosynthesis; v19, rate for removal of cytokinin; v20, transcription rate of the PIN gene; v21, rare for the decay of PIN mRNA; v22, translation rate of PIN protein; v23, rate for decay of PIN protein in cytosol; v24, rate for transport of PIN protein from cytosol to plasma membrane; v25, rate for internalization of PIN protein. When exogenous hormones are applied: v26, rate for uptake of IAA when exogenous IAA is applied; v27, rate for uptake of ACC when exogenous ACC is applied; v28, rate for uptake of cytokinin when exogenous cytokinin is applied.
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Figure 2: A hormonal crosstalk network of auxin, ethylene and cytokinin for root development, showing that change in one signaling component leads to change in other signaling components in the network (modified with permission from Liu et al., 2013). The reaction rates are: v1, total auxin influx from all neighboring; v2, auxin biosynthesis rate in the cell; v3, total auxin efflux from the cell; v4, rate for conversion of the inactive form of the auxin receptor, Ra, to its active form, Ra*; v5, rate for conversion of the active form of the auxin receptor, Ra*, to its inactive form, Ra; v6, transcription rate of the POLARIS (PLS)gene; v7, decay rate of PLS mRNA; v8, translation rate of the PLS protein; v9, decay rate of PLS protein; v10, rate for conversion of the inactive form of the ethylene receptor, Re, to its active form by PLS protein (PLSp), Re*; v11, rate for conversion of the active form of ethylene receptor, Re*, to its inactive form, Re; v12, ethylene biosynthesis rate; v13, rate for removal of ethylene; v14, rate for conversion of the inactive form of the CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) protein, CTR1, to its active form, CTR1*; v15, rate for conversion of the active form of CTR1 protein, CTR1*, to its inactive form, CTR1; v16, rate for activation of the ethylene signaling response; v17, rate for removal of the unknown ethylene signaling component, X; v18, rate for cytokinin biosynthesis; v19, rate for removal of cytokinin; v20, transcription rate of the PIN gene; v21, rare for the decay of PIN mRNA; v22, translation rate of PIN protein; v23, rate for decay of PIN protein in cytosol; v24, rate for transport of PIN protein from cytosol to plasma membrane; v25, rate for internalization of PIN protein. When exogenous hormones are applied: v26, rate for uptake of IAA when exogenous IAA is applied; v27, rate for uptake of ACC when exogenous ACC is applied; v28, rate for uptake of cytokinin when exogenous cytokinin is applied.

Mentions: By combining the experimental data relating to the PLS gene with a variety of other experimental data in the literature, we have revealed that PLS, PIN1/PIN2, and three hormones (auxin, ethylene and cytokinin) form an interacting network (Figure 2), in which expression of PLS and PIN1/PIN2 levels regulate auxin, ethylene and cytokinin responses, which in turn regulate expression of PLS and PIN1/PIN2 (Liu et al., 2013). In addition, changing the concentration of, or response to a given hormone may also change the concentrations of/responses to other hormones. Therefore, functions of hormones and the associated genes in root development must be analyzed as an integrative system, as exemplified in Figure 2.


Hormonal crosstalk for root development: a combined experimental and modeling perspective.

Liu J, Rowe J, Lindsey K - Front Plant Sci (2014)

A hormonal crosstalk network of auxin, ethylene and cytokinin for root development, showing that change in one signaling component leads to change in other signaling components in the network (modified with permission from Liu et al., 2013). The reaction rates are: v1, total auxin influx from all neighboring; v2, auxin biosynthesis rate in the cell; v3, total auxin efflux from the cell; v4, rate for conversion of the inactive form of the auxin receptor, Ra, to its active form, Ra*; v5, rate for conversion of the active form of the auxin receptor, Ra*, to its inactive form, Ra; v6, transcription rate of the POLARIS (PLS)gene; v7, decay rate of PLS mRNA; v8, translation rate of the PLS protein; v9, decay rate of PLS protein; v10, rate for conversion of the inactive form of the ethylene receptor, Re, to its active form by PLS protein (PLSp), Re*; v11, rate for conversion of the active form of ethylene receptor, Re*, to its inactive form, Re; v12, ethylene biosynthesis rate; v13, rate for removal of ethylene; v14, rate for conversion of the inactive form of the CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) protein, CTR1, to its active form, CTR1*; v15, rate for conversion of the active form of CTR1 protein, CTR1*, to its inactive form, CTR1; v16, rate for activation of the ethylene signaling response; v17, rate for removal of the unknown ethylene signaling component, X; v18, rate for cytokinin biosynthesis; v19, rate for removal of cytokinin; v20, transcription rate of the PIN gene; v21, rare for the decay of PIN mRNA; v22, translation rate of PIN protein; v23, rate for decay of PIN protein in cytosol; v24, rate for transport of PIN protein from cytosol to plasma membrane; v25, rate for internalization of PIN protein. When exogenous hormones are applied: v26, rate for uptake of IAA when exogenous IAA is applied; v27, rate for uptake of ACC when exogenous ACC is applied; v28, rate for uptake of cytokinin when exogenous cytokinin is applied.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3975122&req=5

Figure 2: A hormonal crosstalk network of auxin, ethylene and cytokinin for root development, showing that change in one signaling component leads to change in other signaling components in the network (modified with permission from Liu et al., 2013). The reaction rates are: v1, total auxin influx from all neighboring; v2, auxin biosynthesis rate in the cell; v3, total auxin efflux from the cell; v4, rate for conversion of the inactive form of the auxin receptor, Ra, to its active form, Ra*; v5, rate for conversion of the active form of the auxin receptor, Ra*, to its inactive form, Ra; v6, transcription rate of the POLARIS (PLS)gene; v7, decay rate of PLS mRNA; v8, translation rate of the PLS protein; v9, decay rate of PLS protein; v10, rate for conversion of the inactive form of the ethylene receptor, Re, to its active form by PLS protein (PLSp), Re*; v11, rate for conversion of the active form of ethylene receptor, Re*, to its inactive form, Re; v12, ethylene biosynthesis rate; v13, rate for removal of ethylene; v14, rate for conversion of the inactive form of the CONSTITUTIVE TRIPLE RESPONSE 1 (CTR1) protein, CTR1, to its active form, CTR1*; v15, rate for conversion of the active form of CTR1 protein, CTR1*, to its inactive form, CTR1; v16, rate for activation of the ethylene signaling response; v17, rate for removal of the unknown ethylene signaling component, X; v18, rate for cytokinin biosynthesis; v19, rate for removal of cytokinin; v20, transcription rate of the PIN gene; v21, rare for the decay of PIN mRNA; v22, translation rate of PIN protein; v23, rate for decay of PIN protein in cytosol; v24, rate for transport of PIN protein from cytosol to plasma membrane; v25, rate for internalization of PIN protein. When exogenous hormones are applied: v26, rate for uptake of IAA when exogenous IAA is applied; v27, rate for uptake of ACC when exogenous ACC is applied; v28, rate for uptake of cytokinin when exogenous cytokinin is applied.
Mentions: By combining the experimental data relating to the PLS gene with a variety of other experimental data in the literature, we have revealed that PLS, PIN1/PIN2, and three hormones (auxin, ethylene and cytokinin) form an interacting network (Figure 2), in which expression of PLS and PIN1/PIN2 levels regulate auxin, ethylene and cytokinin responses, which in turn regulate expression of PLS and PIN1/PIN2 (Liu et al., 2013). In addition, changing the concentration of, or response to a given hormone may also change the concentrations of/responses to other hormones. Therefore, functions of hormones and the associated genes in root development must be analyzed as an integrative system, as exemplified in Figure 2.

Bottom Line: Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in developmental biology.Although a localized auxin concentration maximum in the root tip is important for root development, auxin concentration cannot change independently of multiple interacting hormones and genes.Moreover, we discuss that experimental evidence showing that, in root development, hormones and the associated regulatory and target genes form a network, in which relevant genes regulate hormone activities and hormones regulate gene expression.

View Article: PubMed Central - PubMed

Affiliation: The Integrative Cell Biology Laboratory, School of Biological and Biomedical Sciences, The Biophysical Sciences Institute, Durham University Durham, UK.

ABSTRACT
Plants are sessile organisms and therefore they must adapt their growth and architecture to a changing environment. Understanding how hormones and genes interact to coordinate plant growth in a changing environment is a major challenge in developmental biology. Although a localized auxin concentration maximum in the root tip is important for root development, auxin concentration cannot change independently of multiple interacting hormones and genes. In this review, we discuss the experimental evidence showing that the POLARIS peptide of Arabidopsis plays an important role in hormonal crosstalk and root growth, and review the crosstalk between auxin and other hormones for root growth with and without osmotic stress. Moreover, we discuss that experimental evidence showing that, in root development, hormones and the associated regulatory and target genes form a network, in which relevant genes regulate hormone activities and hormones regulate gene expression. We further discuss how it is increasingly evident that mathematical modeling is a valuable tool for studying hormonal crosstalk. Therefore, a combined experimental and modeling study on hormonal crosstalk is important for elucidating the complexity of root development.

No MeSH data available.


Related in: MedlinePlus