Content and Metabolism of Indole-3-acetic Acid (IAA) in Healthy and Rust-Infected Wheat Leaf Segments

Abstract The content of IAA in stem rust-infected susceptible wheat leaves shows a highly pronounced maximum 5-6 days after inoculation, shortly prior to the onset of sporulation. This auxin increase can not only be caused by a reduced degradation of IAA. Considerable amounts of IAA are also found in urediospores and germlings; the IAA is in part released by them into the germination medium. IAA applied exogenously to wheat leaves is channelled into two different degradation pathways: (a) into the peroxidase-catalysed decarboxylation which leads to indole-3-methanol and subsequent products as well as into (b) a non-decarboxylative path which leads to a number of oxindolic compounds. Furthermore, IAA conjugates such as IAAglc and IAAsp are formed. The formation of the products is characteristically dependent upon the concentration of the IAA applied. In rust fungus-infected wheat leaves, all IAA metabolites occur which are known in healthy leaves. The mode of their formation after “feeding” of radioactively-labelled IAA leads to the conclusion that the main part of the IAA in the infected leaves is present in a pool which does not permit a rapid exchange with the IAA taken up. The results lead to the hypothesis that IAA is present, to a major extent, in the structures of the fungus and is probably also produced by it.

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THE PHYSIOLOGY OF HOST–PARASITE RELATIONS: XVIII. DISTRIBUTION OF TRITIUM-LABELLED CYTIDINE, URIDINE, AND LEUCINE IN WHEAT LEAVES INFECTED WITH THE STEM RUST FUNGUS

Canadian Journal of Botany ◽

10.1139/b67-062 ◽

1967 ◽

Vol 45 (5) ◽

pp. 555-563 ◽

Cited By ~ 13

Author(s):

P. K. Bhattacharya ◽

Michael Shaw

Keyword(s):

Stem Rust ◽

Rust Fungus ◽

Host Cells ◽

Fungal Mycelium ◽

Puccinia Graminis ◽

Mesophyll Cells ◽

Wheat Leaves ◽

Host Parasite

Wheat leaves were detached 6 days after inoculation with the stem rust fungus (Puccinia graminis var. tritici Erikss. and Henn.) and fed with tritiated leucine, cytidine, uridine, or thymidine. Mesophyll cells in infected zones incorporated more leucine into protein and more cytidine and uridine into RNA than did cells in adjacent uninfected tissue. Leucine, cytidine, and uridine were also heavily incorporated by fungal mycelium and developing uredospores. Grain counts over host nuclei in the infected zone were two to three-fold of those over nuclei in adjacent uninfected zones. There was no detectable incorporation of thymidinemethyl-3H into either the fungus or the host cells. The results are discussed.

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Metabolism of indole-3-acetic acid and indole-3-methanol in wheat leaf segments

Physiologia Plantarum ◽

10.1111/j.1399-3054.1984.tb06111.x ◽

1984 ◽

Vol 61 (1) ◽

pp. 125-129 ◽

Cited By ~ 19

Author(s):

Beatrix Langenbeck-Schwich ◽

Hans J. Grainbow

Keyword(s):

Acetic Acid ◽

Wheat Leaf ◽

Leaf Segments ◽

Indole 3 Acetic Acid

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Chlorinated Auxins—How Does Arabidopsis Thaliana Deal with Them?

International Journal of Molecular Sciences ◽

10.3390/ijms21072567 ◽

2020 ◽

Vol 21 (7) ◽

pp. 2567 ◽

Cited By ~ 2

Author(s):

Antje Walter ◽

Lorenzo Caputi ◽

Sarah O’Connor ◽

Karl-Heinz van Pée ◽

Jutta Ludwig-Müller

Keyword(s):

Arabidopsis Thaliana ◽

Acetic Acid ◽

Model Organism ◽

Wild Type ◽

In Planta ◽

Bacteria And Fungi ◽

Tryptophan Derivatives ◽

Indole 3 Acetic Acid ◽

Iaa Conjugates

Plant hormones have various functions in plants and play crucial roles in all developmental and differentiation stages. Auxins constitute one of the most important groups with the major representative indole-3-acetic acid (IAA). A halogenated derivate of IAA, 4-chloro-indole-3-acetic acid (4-Cl-IAA), has previously been identified in Pisum sativum and other legumes. While the enzymes responsible for the halogenation of compounds in bacteria and fungi are well studied, the metabolic pathways leading to the production of 4-Cl-IAA in plants, especially the halogenating reaction, are still unknown. Therefore, bacterial flavin-dependent tryptophan-halogenase genes were transformed into the model organism Arabidopsis thaliana. The type of chlorinated indole derivatives that could be expected was determined by incubating wild type A. thaliana with different Cl-tryptophan derivatives. We showed that, in addition to chlorinated IAA, chlorinated IAA conjugates were synthesized. Concomitantly, we found that an auxin conjugate synthetase (GH3.3 protein) from A. thaliana was able to convert chlorinated IAAs to amino acid conjugates in vitro. In addition, we showed that the production of halogenated tryptophan (Trp), indole-3-acetonitrile (IAN) and IAA is possible in transgenic A. thaliana in planta with the help of the bacterial halogenating enzymes. Furthermore, it was investigated if there is an effect (i) of exogenously applied Cl-IAA and Cl-Trp and (ii) of endogenously chlorinated substances on the growth phenotype of the plants.

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The physiology of host–parasite relations. XIX. Further observations on nucleoprotein changes in wheat leaf nuclei during rust infection

Canadian Journal of Botany ◽

10.1139/b68-003 ◽

1968 ◽

Vol 46 (1) ◽

pp. 11-16 ◽

Cited By ~ 10

Author(s):

P. K. Bhattacharya ◽

Michael Shaw ◽

J. M. Naylor

Keyword(s):

Stem Rust ◽

Rust Fungus ◽

Puccinia Graminis ◽

Mesophyll Cells ◽

Rust Infection ◽

Puccinia Graminis Tritici ◽

Wheat Leaf ◽

Host Parasite

Cytophotometric measurements of DNA (Feulgen) and protein-bound lysine and arginine (fluorodinitrobenzene-Sakaguchi) were made on nuclei in mesophyll cells of infected and uninfected leaves of Little Club wheat at intervals of 2 to 4 days up to 13 days after inoculation with uredospores of race 15B of the stem rust fungus (Puccinia graminis tritici Erikss. and Henn.). No change in host DNA was found within 6 days after inoculation, but there were marked decreases in protein-bound lysine and arginine as early as 2 days after inoculation. The DNA/lysine and DNA/arginine ratios were higher in rust-affected host nuclei, but infection did not alter the ratio of protein-bound lysine to arginine. In another series of measurements it was shown that rust infection caused striking increases in the volume and the RNA and protein contents of host nucleoli. These changes persisted even in advanced infections.All the results are consistent with our earlier observations and indicate that profound changes in nuclear metabolism are induced by infection with the rust fungus.

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Indole-3-methanol-β-D-glucoside and indole-3-carboxylic acid-β-D-glucoside are products of indole-3-acetic acid degradation in wheat leaf segments

Phytochemistry ◽

10.1016/s0031-9422(00)84487-8 ◽

1986 ◽

Vol 25 (11) ◽

pp. 2451-2455 ◽

Cited By ~ 15

Author(s):

Gertrud Wiese ◽

Hans J. Grambow

Keyword(s):

Acetic Acid ◽

Carboxylic Acid ◽

Acid Degradation ◽

Wheat Leaf ◽

Leaf Segments ◽

Indole 3 Acetic Acid

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The Effect of Stem Rust Infection on the Soluble Proteins of Wheat Leaves

Australian Journal of Biological Sciences ◽

10.1071/bi9660895 ◽

1966 ◽

Vol 19 (5) ◽

pp. 895 ◽

Cited By ~ 14

Author(s):

CW Wrigley ◽

HL Webster

Keyword(s):

Stem Rust ◽

Electrophoretic Pattern ◽

Soluble Proteins ◽

Wheat Varieties ◽

Disk Electrophoresis ◽

Rust Infection ◽

Electrophoretic Patterns ◽

Wheat Leaf ◽

Wheat Leaves

The soluble proteins of wheat leaf and of stem rust uredospores were resolved into about 28 and 34 components, respectively, by disk electrophoresis. The funguscontaining and the fungus-free areas of infected wheat leaves were examined. The electrophoretic pattern of an extract of the lesions was markedly different from the pattern of an extract of uninfected leaves. Comparison with the pattern of an extract of uredospores suggested that some of these differences were due to contamination with fungal proteins. For susceptible varieties, extracts of the extralesion areas of infected leaves showed different electrophoretic patterns from extracts of uninfected leaves. This was not so for resistant wheat varieties.

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Daylength affects both free and conjugated indole-3-acetic acid levels in leaves and flowering in Doritis pulcherrima (orchid)

Canadian Journal of Plant Science ◽

10.4141/p03-162 ◽

2004 ◽

Vol 84 (3) ◽

pp. 881-883

Author(s):

Chiung-Kuei Huang, Wen-Shaw Chen ◽

Yun-An Chen

Keyword(s):

Acetic Acid ◽

Key Words ◽

Floral Initiation ◽

Short Day ◽

Long Day ◽

Photoperiodic Treatment ◽

High Level ◽

Indole 3 Acetic Acid ◽

Iaa Conjugates

Total indole-3-acetic acid (IAA) levels (free IAA plus IAA conjugates) in Doritis pulcherrima (Doritis pulcherrima Lindley, cv. S 84-335-2) leaves were threefold lower in plants exposed to 30 d of short-day (SD) conditions than in plants exposed to 30 d of long-day (LD) conditions. Free IAA levels were also significantly lower in SD-treated leaves than those in 0 day of photoperiodic treatment and 30 d of LD. Results indicate that plants exposed to 30 d of SD contained significantly higher levels of ester-IAA and reduced amide-IAA concentrations compared to those grown under LD conditions. A high level of ester-IAA and a reduction of amide-IAA in leaves may be related to increased SD floral initiation ability in D. pulcherrima. Key words: Doritis pulcherrima, floral initiation, indole-3-acetic acid, photoperiod

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Metabolism of alicyclic acids and phenylpropanoids by uredospores of wheat stem rust and wheat leaf rust

Canadian Journal of Botany ◽

10.1139/b70-157 ◽

1970 ◽

Vol 48 (6) ◽

pp. 1085-1091

Author(s):

A. O. Jackson ◽

D. J. Samborski ◽

R. Rohringer

Keyword(s):

Leaf Rust ◽

Phenolic Acids ◽

Stem Rust ◽

Phenylalanine Ammonia Lyase ◽

Wheat Leaf Rust ◽

Shikimate Dehydrogenase ◽

Wheat Stem Rust ◽

Germination Medium ◽

Tyrosine Ammonia Lyase ◽

Wheat Leaf

Uredospores of wheat leaf rust did not take up or metabolize exogenous supplies of quinate-U-14C, shikimate-U-14C, p-coumarate-α-14C, or ferulate-α-14C. Caffeate-α-14C was converted to an unidentified ether-insoluble component which was recovered from the germination medium.Phenylalanine-U-14C and tyrosine-U-14C were readily taken up by uredospores of both rusts and were recovered from the solvent-soluble and insoluble fractions. No evidence for phenylalanine/tyrosine interconversion was obtained. Radioactivity was not incorporated into glycosides or free and bound esters of phenolic acids when phenylalanine-U-14C or tyrosine-U-14C were used as precursors. Radioactivity was not detected in free phenolic acids when uredospores were fed phenylalanine-U-14C. When tyrosine-U-14C was the precursor, radioactive p-coumarate was detected in the germination medium kept at 20 °C, and radioactive p-coumarate and caffeate were both recovered from the germination medium kept at 30 °C.Extracts of uredospores of wheat stem rust and wheat leaf rust contained shikimate dehydrogenase and tyrosine ammonia-lyase. Quinate dehydrogenase and phenylalanine ammonia-lyase were not detected.

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