A deletion in an indole synthase gene is responsible for the DIMBOA-deficient phenotype of bxbx maize

The biosynthesis of DIMBOA, a pesticidal secondary metabolite of maize, branches off the tryptophan pathway. We have previously demonstrated that indole is the last intermediate common to both the tryptophan and hydroxamic acid pathways. The earliest discovered mutant in the DIMBOA pathway, bxbx (benzoxazineless), is deficient in the production of DIMBOA and related compounds. This paper presents evidence that a gene identified by Kramer and Koziel [Kramer, V. C. & Koziel, M. G. (1995) Plant Mol. Biol. 27, 1183–1188] as maize tryptophan synthase α (TSA) is the site of the genetic lesion in the DIMBOA-deficient mutant maize line bxbx. We demonstrate that the TSA gene has sustained a 924-bp deletion in bxbx compared with its counterpart in wild-type maize. We report that the TSA gene maps to the same location as the bxbx mutation, on the short arm of chromosome 4. We present evidence that the very early and very high level of expression of TSA corresponds to the timing and level of DIMBOA biosynthesis but is strikingly different from the expression of the maize tryptophan synthase β (TSB) genes. We show that feeding indole to bxbx seedlings restores their ability to synthesize DIMBOA. We conclude that the maize enzyme initially named tryptophan synthase α in fact is a DIMBOA biosynthetic enzyme, and we propose that it be renamed indole synthase. This work confirms and enlarges upon the findings of Frey et al. [Frey, M. Chomet, P., Glawischniq, E., Stettner, C., Grün, S., Winklmair, A., Eisenreich, W., Bacher, A., Meeley, R. B., Briggs, S. P., Simcox, K. & Gierl, A. (1997) Science 277, 696–699], which appeared while the present paper was in review.

Involvement of the Octadecanoid Pathway and Protein Phosphorylation in Fungal Elicitor-Induced Expression of Terpenoid Indole Alkaloid Biosynthetic Genes in Catharanthus roseus

Two key genes in terpenoid indole alkaloid biosynthesis, Tdc and Str, encoding tryptophan decarboxylase and strictosidine synthase, respectively, are coordinately induced by fungal elicitors in suspension-cultured Catharanthus roseus cells. We have studied the roles of the jasmonate biosynthetic pathway and of protein phosphorylation in signal transduction initiated by a partially purified elicitor from yeast extract. In addition to activating Tdc and Str gene expression, the elicitor also induced the biosynthesis of jasmonic acid. The jasmonate precursor α-linolenic acid or methyl jasmonate (MeJA) itself induced Tdc and Str gene expression when added exogenously . Diethyldithiocarbamic acid, an inhibitor of jasmonate biosynthesis, blocked both the elicitor-induced formation of jasmonic acid and the activation of terpenoid indole alkaloid biosynthetic genes. The protein kinase inhibitor K-252a abolished both elicitor-induced jasmonate biosynthesis and MeJA-induced Tdc and Str gene expression. Analysis of the expression of Str promoter/gusA fusions in transgenic C. roseus cells showed that the elicitor and MeJA act at the transcriptional level. These results demonstrate that the jasmonate biosynthetic pathway is an integral part of the elicitor-triggered signal transduction pathway that results in the coordinate expression of the Tdc and Str genes and that protein kinases act both upstream and downstream of jasmonates.

An in Vitro System from Maize Seedlings for Tryptophan-Independent Indole-3-Acetic Acid Biosynthesis1

The enzymatic synthesis of indole-3-acetic acid (IAA) from indole by an in vitro preparation from maize (Zea mays L.) that does not use tryptophan (Trp) as an intermediate is described. Light-grown seedlings of normal maize and the maize mutant orange pericarp were shown to contain the necessary enzymes to convert [14C]indole to IAA. The reaction was not inhibited by unlabeled Trp and neither [14C]Trp nor [14C]serine substituted for [14C]indole in this in vitro system. The reaction had a pH optimum greater than 8.0, required a reducing environment, and had an oxidation potential near that of ascorbate. The results obtained with this in vitro enzyme preparation provide strong, additional evidence for the presence of a Trp-independent IAA biosynthesis pathway in plants.

Metabolism of Indole-3-Acetic Acid in Arabidopsis1

The metabolism of indole-3-acetic acid (IAA) was investigated in 14-d-old Arabidopsis plants grown in liquid culture. After ruling out metabolites formed as an effect of nonsterile conditions, high-level feeding, and spontaneous interconversions, a simple metabolic pattern emerged. Oxindole-3-acetic acid (OxIAA), OxIAA conjugated to a hexose moiety via the carboxyl group, and the conjugates indole-3-acetyl aspartic acid (IAAsp) and indole-3-acetyl glutamate (IAGlu) were identified by mass spectrometry as primary products of IAA fed to the plants. Refeeding experiments demonstrated that none of these conjugates could be hydrolyzed back to IAA to any measurable extent at this developmental stage. IAAsp was further oxidized, especially when high levels of IAA were fed into the system, yielding OxIAAsp and OH-IAAsp. This contrasted with the metabolic fate of IAGlu, since that conjugate was not further metabolized. At IAA concentrations below 0.5 μm, most of the supplied IAA was metabolized via the OxIAA pathway, whereas only a minor portion was conjugated. However, increasing the IAA concentrations to 5 μm drastically altered the metabolic pattern, with marked induction of conjugation to IAAsp and IAGlu. This investigation used concentrations for feeding experiments that were near endogenous levels, showing that the metabolic pathways controlling the IAA pool size in Arabidopsis are limited and, therefore, make good targets for mutant screens provided that precautions are taken to avoid inducing artificial metabolism.

Indole-3-Acetic Acid Controls Cambial Growth in Scots Pine by Positional Signaling1

The vascular cambium produces secondary xylem and phloem in plants and is responsible for wood formation in forest trees. In this study we used a microscale mass-spectrometry technique coupled with cryosectioning to visualize the radial concentration gradient of endogenous indole-3-acetic acid (IAA) across the cambial meristem and the differentiating derivatives in Scots pine (Pinus sylvestris L.) trees that had different rates of cambial growth. This approach allowed us to investigate the relationship between growth rate and the concentration of endogenous IAA in the dividing cells. We also tested the hypothesis that IAA is a positional signal in xylem development (C. Uggla, T. Moritz, G. Sandberg, B. Sundberg [1996] Proc Natl Acad Sci USA 93: 9282–9286). This idea postulates that the width of the radial concentration gradient of IAA regulates the radial number of dividing cells in the cambial meristem, which is an important component for determining cambial growth rate. The relationship between IAA concentration in the dividing cells and growth rate was poor, although the highest IAA concentration was observed in the fastest-growing cambia. The radial width of the IAA concentration gradient showed a strong correlation with cambial growth rate. The results indicate that IAA gives positional information in plants.

De origine et indole arabicae librorum V.T. historicorum interpretationis libri duo.

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D. Lud. Gottfred. Kleinii ... Interpres clinicus, sive De morborum indole, exitu in sanitatem, metaschematismo, successionibus, evento funesto, dijudicationes, praesagitiones medicae, pagellae in memoriae subsidium medicis junioribus, ad infirmos ingressuris, fideliter communicatae /

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Observationum Felicis Plateri ... libri tres totidem praxeos eius tractatibus, indole & methodo respondentes, atque affectuum corporis & animi plurimorum tum historias fide ac sedulo observatas, tum curationes feliciter praestitas, graphice enarrantes ; Tertia nunc vice typis mandati, ac praeter medicamentorum anakephalaiosin, & indicem rerum fructuosissimum, secunda editione, adjecta; ab innumeris mendis, in prioribus duabus, praetermissis, repurgati. Nova insuper, Fel. Plateri, Fel. ex Fr. nep. selectiorum observationum Mantissa, locupletati /

Contiene con port. y paginación propias: Felicis Plateri ... Observationum selectiorum ... Mantissa ...

D. Lud. Gottfr. Kleinii ... Interpres clinicus sive De morborum indole, exitu in sanitatem, Metaschematismo, successionibus, eventu funesto dijudicationes, praesagitiones medicae : pagellae in memoriae subsidium medicis junioribus ad infirmos ingressuris, fideliter communicatae comitatur opusculum /

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D. Lud. Gotfr. Kleinii ... Interpres clinicus sive De morborum indole, exitu in sanitatem, Metaschematismo, successionibus, eventu funesto diiudicationes, praesagitiones medicae, pagellae in memoriae subsidium medicis iunioribus ad infirmos ingressuris, fideliter communicatae comitatur opusculum /

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Interpres clinicus D. Lud. Gotfr. Kleinii ... sive dijudicationes, et praesagitiones medicae de morborum indole ... /

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Iohannis Linder ... De venenis in genere & in specie exercitatio : videlicet, eorum natura & in corpus agendi modo atque eadem, pro morbi acuti vel chronici ex iisdem oborientis indole , curandi : & in esculentis, potulentisque indagandi ratione juxta veterum quorundam & recentiorum dogmata ad solidorum & fluidorum corporis organici leges mechanicas deducta & explicata.

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Compendio de la vida y hechos de Joseph Balsamo llamado el conde calliostro : que se ha sacado del proceso formado contra él en Roma el año de 1790, y que puede servir de regla para conocer la indole de la secta de los francsmasones /

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Petri Tamburini Brixiani ... De fontibus sacrae theologiae deq. constitutione et indole ecclesiae christianae, eiusque regimine : volumen II, De Verbo Dei ...

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Haereticus Araneus, ex cuius natura et indole vniuersa haereseos oeconomia et technae liquidò lepidéque demonstrantur /

ICCU,