Unrevealed structural requirements for auxin-like molecules by theoretical and experimental evidences

Structure–activity profiles for the phytohormone auxin have been collected for over 70 years, and a number of synthetic auxins are used in agriculture. Auxin classification schemes and binding models followed from understanding auxin structures. However, all of the data came from whole plant bioassays, meaning the output was the integral of many different processes. The discovery of Transport Inhibitor-Response 1 (TIR1) and the Auxin F-Box (AFB) proteins as sites of auxin perception and the role of auxin as molecular glue in the assembly of co-receptor complexes has allowed the development of a definitive quantitative structure–activity relationship for TIR1 and AFB5. Factorial analysis of binding activities offered two uncorrelated factors associated with binding efficiency and binding selectivity. The six maximum-likelihood estimators of Efficiency are changes in the overlap matrixes, inferring that Efficiency is related to the volume of the electronic system. Using the subset of compounds that bound strongly, chemometric analyses based on quantum chemical calculations and similarity and self-similarity indices yielded three classes of Specificity that relate to differential binding. Specificity may not be defined by any one specific atom or position and is influenced by coulomb matrixes, suggesting that it is driven by electrostatic forces. These analyses give the first receptor-specific classification of auxins and indicate that AFB5 is the preferred site for a number of auxinic herbicides by allowing interactions with analogues having van der Waals surfaces larger than that of indole-3-acetic acid. The quality factors are also examined in terms of long-standing models for the mechanism of auxin binding.

show abstract

“…The most recent work also accepted that the system needed to account for more than one family of receptors. 12,27 …”

Section: Resultsmentioning

confidence: 99%

Defining Binding Efficiency and Specificity of Auxins for SCF^TIR1/AFB-Aux/IAA Co-receptor Complex Formation

et al. 2013

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, the chemical space, which encompasses the term "auxin," is actually not easily achieved, since many compounds were found to exhibit an auxin-like activity in several different bioassays (Ferro et al, 2007). Our compar- ative analysis of auxin activity for IAA, IAAld, and IEt (Fig.…”

Section: Iaald Shows Auxin-like Activity In Arabidopsismentioning

confidence: 99%

Trichoderma virens, a Plant Beneficial Fungus, Enhances Biomass Production and Promotes Lateral Root Growth through an Auxin-Dependent Mechanism in Arabidopsis

et al. 2009

View full text Add to dashboard Cite

Trichoderma species belong to a class of free-living fungi beneficial to plants that are common in the rhizosphere. We investigated the role of auxin in regulating the growth and development of Arabidopsis (Arabidopsis thaliana) seedlings in response to inoculation with Trichoderma virens and Trichoderma atroviride by developing a plant-fungus interaction system. Wild-type Arabidopsis seedlings inoculated with either T. virens or T. atroviride showed characteristic auxin-related phenotypes, including increased biomass production and stimulated lateral root development. Mutations in genes involved in auxin transport or signaling, AUX1, BIG, EIR1, and AXR1, were found to reduce the growth-promoting and root developmental effects of T. virens inoculation. When grown under axenic conditions, T. virens produced the auxin-related compounds indole-3-acetic acid, indole-3-acetaldehyde, and indole-3-ethanol. A comparative analysis of all three indolic compounds provided detailed information about the structure-activity relationship based on their efficacy at modulating root system architecture, activation of auxin-regulated gene expression, and rescue of the root hair-defective phenotype of the rhd6 auxin response Arabidopsis mutant. Our results highlight the important role of auxin signaling for plant growth promotion by T. virens.

show abstract

“…Its analogues have already been patented as herbicides (Takematsu et al, 1986). Additionally, this core structure is present in auxin-like molecules (Ferro et al, 2007). Interestingly, the order of plant growth inhibitory effects of 5 and 11 correlated with plant growth activity of hydro-1-naphthoic acid derivatives that 6-methyl-l,2,3,4-tetrahydro-l-naphthoic acid (minimum concentration causing a 10% elongation: 0.08 mM) and 6-methyl-3,4-dihydro-1-naphthoic acid (minimum concentration causing a 10% elongation: 0.5 mM) evaluated using the pea straight-growth test (Fujita et al, 1967) (Table 1).…”

Section: Plant Growth Inhibitory Activity Of Rinsate Constituentsmentioning

confidence: 99%

Phytotoxicity of constituents of glandular trichomes and the leaf surface of camphorweed, Heterotheca subaxillaris

Morimoto

Cantrell²,

Libous-Bailey³

et al. 2009

Phytochemistry

View full text Add to dashboard Cite

Unrevealed structural requirements for auxin-like molecules by theoretical and experimental evidences

Cited by 19 publications

References 60 publications

Defining Binding Efficiency and Specificity of Auxins for SCF^TIR1/AFB-Aux/IAA Co-receptor Complex Formation

Defining Binding Efficiency and Specificity of Auxins for SCF^TIR1/AFB-Aux/IAA Co-receptor Complex Formation

Trichoderma virens, a Plant Beneficial Fungus, Enhances Biomass Production and Promotes Lateral Root Growth through an Auxin-Dependent Mechanism in Arabidopsis

Phytotoxicity of constituents of glandular trichomes and the leaf surface of camphorweed, Heterotheca subaxillaris

Contact Info

Product

Resources

About

Unrevealed structural requirements for auxin-like molecules by theoretical and experimental evidences

Cited by 19 publications

References 60 publications

Defining Binding Efficiency and Specificity of Auxins for SCFTIR1/AFB-Aux/IAA Co-receptor Complex Formation

Defining Binding Efficiency and Specificity of Auxins for SCFTIR1/AFB-Aux/IAA Co-receptor Complex Formation

Trichoderma virens, a Plant Beneficial Fungus, Enhances Biomass Production and Promotes Lateral Root Growth through an Auxin-Dependent Mechanism in Arabidopsis

Phytotoxicity of constituents of glandular trichomes and the leaf surface of camphorweed, Heterotheca subaxillaris

Contact Info

Product

Resources

About

Defining Binding Efficiency and Specificity of Auxins for SCF^TIR1/AFB-Aux/IAA Co-receptor Complex Formation

Defining Binding Efficiency and Specificity of Auxins for SCF^TIR1/AFB-Aux/IAA Co-receptor Complex Formation