Some chemical and physiological properties of 3-indolylpyruvic acid

Bentley, J. A.; Farrar, Kathleen R.; Housley, Stephen N.; Smith, G. F.; Taylor, W. C.

doi:10.1042/bj0640044

Cited by 86 publications

(23 citation statements)

References 7 publications

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“…The administration of other IAA precursors (0.25 mM), such as TAM, IAM, IAN, or TOL, did not enhance the production of IAA. Experiments with IPA remained inconclusive as the precursor proved to be unstable and generated IAA spontaneously (46,47). Interestingly, the incubation with 0.2 mM IAD yielded the largest amount of IAA, 140.39 M. Figure 2 tryptophan.…”

Section: Resultsmentioning

confidence: 99%

Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza

Krause

Henke

Asiimwe

et al. 2015

Appl Environ Microbiol

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bFungus-derived indole-3-acetic acid (IAA), which is involved in development of ectomycorrhiza, affects both partners, i.e., the tree and the fungus. The biosynthesis pathway, excretion from fungal hyphae, the induction of branching in fungal cultures, and enhanced Hartig net formation in mycorrhiza were shown. Gene expression studies, incorporation of labeled compounds into IAA, heterologous expression of a transporter, and bioinformatics were applied to study the effect of IAA on fungal morphogenesis and on ectomycorrhiza. Tricholoma vaccinum produces IAA from tryptophan via indole-3-pyruvate, with the last step of this biosynthetic pathway being catalyzed by an aldehyde dehydrogenase. The gene ald1 was found to be highly expressed in ectomycorrhiza and induced by indole-3-acetaldehyde. The export of IAA from fungal cells is supported by the multidrug and toxic extrusion (MATE) transporter Mte1 found in T. vaccinum. The addition of IAA and its precursors induced elongated cells and hyphal ramification of mycorrhizal fungi; in contrast, in saprobic fungi such as Schizophyllum commune, IAA did not induce morphogenetic changes. Mycorrhiza responded by increasing its Hartig net formation. The IAA of fungal origin acts as a diffusible signal, influencing root colonization and increasing Hartig net formation in ectomycorrhiza. F ungi, mainly basidiomycetes, form a mutually beneficial symbiotic association, commonly known as ectomycorrhiza, with the roots of woody plants (1). After establishing contact with the host, the fungus initially grows around the roots to form a mass of mycelium called the fungal mantle. From there, some hyphae penetrate the roots to grow between cortical cells to form the Hartig net, which acts as a surface for the exchange of nutrients and signals between the two symbiotic partners (1). Variation in host specificity occurs within ectomycorrhizal fungi: some have a broad host range, whereas others form host-specific ectomycorrhiza. In contrast to ectomycorrhizal fungi such as Pisolithus tinctorius and Paxillus involutus, Tricholoma species often show host specificity; their fruiting bodies are found only below compatible host trees. For example, Tricholoma vaccinum fruiting bodies occur only near spruce, which is the compatible host (2). Under laboratory conditions, Tricholoma species form ectomycorrhiza with nonhost trees, but the mycorrhization process in such lowcompatibility interactions requires more time and features spotty Hartig net formation (3). Thus, T. vaccinum, a slow-growing, latestage, and highly host-specific mycorrhizal fungus was chosen for the investigation of fungus-derived phytohormone effects on both partners. These interactions were expected to show the importance of indole-3-acetic acid (IAA) in the establishment and functioning of the symbiosis. We hypothesized that a long period of incubation might be necessary to observe changes in the morphogenetic responses that are not easily visualized with fast-growing, early-stage mycorrhiza. In order to generalize our findin...

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Section: Resultsmentioning

confidence: 99%

Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza

Krause

Henke

Asiimwe

et al. 2015

Appl Environ Microbiol

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“…IPA is an enzymatic reaction product of TAA1 in vitro. IPA is a relatively unstable IAA precursor and nonenzymatically converted to IAA in aqueous solution (35). To avoid the degradation of IPA during the purification, we immediately derivatized IPA with dinitrophenyl hydrazine (DNPH) to a stable hydrazone derivative (DNPH-IPA) in the crude extracts (Fig.…”

Section: Resultsmentioning

confidence: 99%

The main auxin biosynthesis pathway in Arabidopsis

Mashiguchi

Tanaka

Sakai

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

847

720

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The phytohormone auxin plays critical roles in the regulation of plant growth and development. Indole-3-acetic acid (IAA) has been recognized as the major auxin for more than 70 y. Although several pathways have been proposed, how auxin is synthesized in plants is still unclear. Previous genetic and enzymatic studies demonstrated that both TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA) and YUCCA (YUC) flavin monooxygenase-like proteins are required for biosynthesis of IAA during plant development, but these enzymes were placed in two independent pathways. In this article, we demonstrate that the TAA family produces indole-3-pyruvic acid (IPA) and the YUC family functions in the conversion of IPA to IAA in Arabidopsis (Arabidopsis thaliana) by a quantification method of IPA using liquid chromatography-electrospray ionization-tandem MS. We further show that YUC protein expressed in Escherichia coli directly converts IPA to IAA. Indole-3-acetaldehyde is probably not a precursor of IAA in the IPA pathway. Our results indicate that YUC proteins catalyze a rate-limiting step of the IPA pathway, which is the main IAA biosynthesis pathway in Arabidopsis.plant hormone | metabolism

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“…5). It is well-known that IPA is very labile in aqueous solutions and that IPA is easily converted to IAA in vitro nonenzymatically (19). It will be necessary to redo the IAA analysis in the yuc mutants by removing IPA first.…”

Section: Discussionmentioning

confidence: 99%

Conversion of tryptophan to indole-3-acetic acid by TRYPTOPHAN AMINOTRANSFERASES OF ARABIDOPSIS and YUCCAs in Arabidopsis

Won

Shen

Mashiguchi³

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

577

554

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Auxin is an essential hormone, but its biosynthetic routes in plants have not been fully defined. In this paper, we show that the TRYPTOPHAN AMINOTRANSFERASE OF ARABIDOPSIS (TAA) family of amino transferases converts tryptophan to indole-3-pyruvate (IPA) and that the YUCCA (YUC) family of flavin monooxygenases participates in converting IPA to indole-3-acetic acid, the main auxin in plants. Both the YUCs and the TAAs have been shown to play essential roles in auxin biosynthesis, but it has been suggested that they participate in two independent pathways. Here, we show that all of the taa mutant phenotypes, including defects in shade avoidance, root resistance to ethylene and N-1-naphthylphthalamic acid (NPA), are phenocopied by inactivating YUC genes. On the other hand, we show that the taa mutants in several known auxin mutant backgrounds, including pid and npy1, mimic all of the well-characterized developmental defects caused by combining yuc mutants with the auxin mutants. Furthermore, we show that overexpression of YUC1 partially suppresses the shade avoidance defects of taa1 and the sterile phenotypes of the weak but not the strong taa mutants. In addition, we discovered that the auxin overproduction phenotypes of YUC overexpression lines are dependent on active TAA genes. Our genetic data show that YUC and TAA work in the same pathway and that YUC is downstream of TAA. The yuc mutants accumulate IPA, and the taa mutants are partially IPA-deficient, indicating that TAAs are responsible for converting tryptophan to IPA, whereas YUCs play an important role in converting IPA to indole-3-acetic acid.

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Some chemical and physiological properties of 3-indolylpyruvic acid

Cited by 86 publications

References 7 publications

Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza

Biosynthesis and Secretion of Indole-3-Acetic Acid and Its Morphological Effects on Tricholoma vaccinum-Spruce Ectomycorrhiza

The main auxin biosynthesis pathway in Arabidopsis

Conversion of tryptophan to indole-3-acetic acid by TRYPTOPHAN AMINOTRANSFERASES OF ARABIDOPSIS and YUCCAs in Arabidopsis

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