Tryptophan-independent auxin biosynthesis contributes to early embryogenesis in
            <i>Arabidopsis</i>

Wang, Bing; Chu, Jinfang; Yu, Tianying; Xu, Qian; Sun, Xiaohong; Jia, Yuping; Xiong, Guosheng; Wang, Guodong; Wang, Yonghong; Li, Jiayang

doi:10.1073/pnas.1503998112

Cited by 180 publications

(128 citation statements)

References 36 publications

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“…Using this newly developed IDP model in combination with physics-based simulations (with solvent), Wang et al recently described the unbound ensembles of the α-MoRE (residues 484-504) located within the intrinsically disordered C-terminal domain of the measles virus (MeV) nucleoprotein (N TAIL ) and deciphered the mechanism by which the α-MoRE recognizes the X domain (XD) of the MeV phosphoprotein. 73 Among experimental techniques providing quantitative information, SAXS and single-molecule approaches, which allow the observation of transient intermediates, have enabled a better understanding of the behavior of IDPs. In particular, SAXS studies, combined with ensemble optimization methods (EOM), have led to low-resolution description of IDPs as realistic conformational ensembles (see ref.…”

Section: Further Quantitative Techniques For Characterizing Structuramentioning

confidence: 99%

“…42 Although conformational selection requires that the IDP populates at least partly the bound state in the free form, which therefore presages the final bound conformation, 194,195 it is important to emphasize that the pre-existence of folded structures in IDPs does not necessarily imply a conformational selection mechanism. 73,210,211 To further complicate the scenario, many IDPs show a high degree of adaptability with respect to the partner (Fig. 16), i.e.…”

Section: Variability Of Binding Modes Attainable By Disordered Proteimentioning

confidence: 99%

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Introducing Protein Intrinsic Disorder

et al. 2014

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Section: Further Quantitative Techniques For Characterizing Structuramentioning

confidence: 99%

Section: Variability Of Binding Modes Attainable By Disordered Proteimentioning

confidence: 99%

Introducing Protein Intrinsic Disorder

et al. 2014

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“…2A; McSteen, 2010;Normanly, 2010;Mashiguchi et al, 2011;Won et al, 2011;Ljung, 2013;Wang et al, 2015): a Trp-dependent route including (1) the indole-3-acetaldoxime (IAOx) pathway, (2) the IAM pathway, (3) the indole-3-pyruvic acid (IPyA) pathway, and (4) the tryptamine (TAM) pathway, as well as a Trp-independent route branching either from indole-3-glycerol phosphate or indole has also been suggested (Wright et al, 1991). Because the scientific community has lacked a strong set of biochemical markers enabling rigorous mapping of the IAA biosynthesis flux network, little is known about the importance of individual pathways as a function of environmental stress.…”

Section: Compensatory Growth Is Associated With Distinct Shifts In Aumentioning

confidence: 99%

Dynamic Precision Phenotyping Reveals Mechanism of Crop Tolerance to Root Herbivory

et al. 2016

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The western corn rootworm (WCR; Diabrotica virgifera virgifera LeConte) is a major pest of maize (Zea mays) that is well adapted to most crop management strategies. Breeding for tolerance is a promising alternative to combat WCR but is currently constrained by a lack of physiological understanding and phenotyping tools. We developed dynamic precision phenotyping approaches using 11 C with positron emission tomography, root autoradiography, and radiometabolite flux analysis to understand maize tolerance to WCR. Our results reveal that WCR attack induces specific patterns of lateral root growth that are associated with a shift in auxin biosynthesis from indole-3-pyruvic acid to indole-3-acetonitrile. WCR attack also increases transport of newly synthesized amino acids to the roots, including the accumulation of Gln. Finally, the regrowth zones of WCR-attacked roots show an increase in Gln turnover, which strongly correlates with the induction of indole-3-acetonitrile-dependent auxin biosynthesis. In summary, our findings identify local changes in the auxin biosynthesis flux network as a promising marker for induced WCR tolerance.

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“…Indole or indole-3-glycerol phosphate, precursors of Trp, have been proposed as the branch point to Trp-I IAA biosynthesis (Ouyang et al 2000) and recent work suggests that a cytosolic tryptophan synthase a-subunit called indole synthase (INS) participates in Trp-I IAA synthesis in embryogenesis in Arabidopsis (Wang et al 2015). Indirect evidence comes from analysis of the Arabidopsis alf3-1 mutant, which produces lateral roots that arrest growth and die after the initial stages of lateral root formation (Celenza et al 1995).…”

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Auxin and Tryptophan Homeostasis Are Facilitated by the ISS1/VAS1 Aromatic Aminotransferase in Arabidopsis

et al. 2015

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Indole-3-acetic acid (IAA) plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophanindependent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 (Indole Severe Sensitive) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1, but not WT, uses primarily Trp-I IAA synthesis when grown on indole-supplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutant's increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways.KEYWORDS Arabidopsis thaliana; auxin; ISS1/VAS1; phenylpropanoids; tryptophan metabolism I N plants, the aromatic amino acids tryptophan (Trp), tyrosine (Tyr), and phenylalanine (Phe) are used for the synthesis of proteins and as precursors to a variety of specialized metabolites. While most secondary metabolites help protect the plant against abiotic and biotic stress (Tzin and Galili 2010), some such as Trp-derived indole-3-acetic acid (IAA) are essential growth regulators (Woodward and Bartel 2005). IAA, the primary auxin in plants, functions in establishing cell polarity during embryogenesis (Weijers et al. 2005;Kleine-Vehn et al. 2008), determination of leaf patterning (Bainbridge et al. 2008), and initiation of lateral roots and shoots (Celenza et al. 1995;Peret et al. 2009).There are two general routes proposed for IAA biosynthesis in plants: from a Trp-dependent (Trp-D) pathway or through an indolic precursor of Trp in a Trp-independent (Trp-I) pathway (Woodward and Bartel 2005;Tivendale et al. 2014) (Figure 1). Within the Trp-D IAA biosynthetic pathway, there are three established pathways in plants that lead to IAA production: (i) the indole-3-pyruvic acid (IPA) pathway (ii) the indole-3-acetaldoxime (IAOx) pathway, and (iii) the indole-3-acetamide (IAM) pathway (Figure 1) (Ljung 2013;Zhao 2014).In the IPA pathway, the TAA1 family of Trp aminotransferases converts Trp into IPA (Stepanova et al. 2008;Tao et al. 2008;Yamada et al. 2009;Zhou et al. 2011) followed by the direct conversion to IAA by t...

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Tryptophan-independent auxin biosynthesis contributes to early embryogenesis in Arabidopsis

Cited by 180 publications

References 36 publications

Introducing Protein Intrinsic Disorder

Introducing Protein Intrinsic Disorder

Dynamic Precision Phenotyping Reveals Mechanism of Crop Tolerance to Root Herbivory

Auxin and Tryptophan Homeostasis Are Facilitated by the ISS1/VAS1 Aromatic Aminotransferase in Arabidopsis

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