IAA biosynthesis by the ectomycorrhizal fungus Hebeloma hiemale as affected by different precursors

1989 ◽  
Vol 67 (8) ◽  
pp. 2235-2239 ◽  
Author(s):  
G. Gay ◽  
R. Rouillon ◽  
J. Bernillon ◽  
J. Favre-Bonvin
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Shikimic Acid ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Ectomycorrhizal Fungus ◽  
Limiting Factors ◽  
Symbiotic Association ◽  
Indole 3 Acetic Acid

The effect of different precursors, aromatic amino acids, or intermediates of the shikimate pathway (pathway for aromatic amino acids biosynthesis), on indole-3-acetic acid (IAA) synthesis by the ectomycorrhizal fungus Hebeloma hiemale was studied. This fungus did not release detectable amounts of IAA when cultivated on a medium containing no precursor or supplemented with 1 mM phenylalanine, 1 mM tyrosine or 1 mM shikimic acid. IAA accumulation in culture filtrates was low (0.5 μmol per flask) when the medium was supplemented with 1 mM anthranilic acid. The fungus released 1.6 μmol of IAA when cultivated on a medium containing 1 mM indole and 6.9 μmol in the presence of 1 mM tryptophan. These results were confirmed by studying the ability of crude enzyme extracts to convert these precursors to IAA. Specific IAA synthesizing activity was of the same order when indole or tryptophan were used as precursors. The comparison of in vivo and in vitro activity of IAA synthesizing enzymes demonstrated that a need for tryptophan concentrations higher than 0.1 mM to obtain detectable IAA synthesis is due to the low ratio of tryptophan breakdown into IAA. The inability of H. hiemale to synthesize IAA in the absence of precursors or in the presence of shikimic acid may be ascribed to a very poor endogenous tryptophan accumulation in the hyphae due to feed back inhibition of the anthranilate synthetase by tryptophan. These results indicate that precursor availability in root exudates is probably one of the main limiting factors for IAA release by ectomycorrhizal fungi under symbiotic association. Key words: ectomycorrhizal fungus, Hebeloma, indole-3-acetic acid, tryptophan, indole, shikimate pathway.

scholarly journals Ruminal bioshynthesis of aromatic amino acids from arylacetic acids, glucose, shikimic acid and phenol

1974 ◽  
Vol 31 (3) ◽  
pp. 357-365 ◽  
Author(s):  
S. Kristensen
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Phenylacetic Acid ◽  
Shikimic Acid ◽  
Aromatic Amino Acids ◽  
Hydroxyphenylacetic Acid ◽  
Arylacetic Acids ◽  
First Time ◽  
Indole 3 Acetic Acid

1. Ruminal metabolism of labelled phenylacetic acid, 4-hydroxyphenylacetic acid, indole-3-acetic acid, glucose, shikimic acid, phenol, and serine was studied in vitro by short-term incubation with special reference to incorporation rates into aromatic amino acids.2. Earlier reports on reductive carboxylation of phenylacetic acid and indole-3-acetic acid in the rumen were confirmed and the formation of tyrosine from 4-hydroxyphenylacetic acid was demonstrated for the first time.3. The amount of phenylalanine synthesized from phenylacetic acid was estimated to be 2 mg/1 rumen contents per 24 h, whereas the amount synthesized from glucose might be eight times as great, depending on diet.4. Shikimic acid was a poor precursor of the aromatic amino acids, presumably owing to its slow entry into rumen bacteria.5. A slow conversion of phenol into tyrosine was observed.

Effect of the ectomycorrhizal fungus Hebeloma hiemale on adventitious root formation in derooted Pinus halepensis shoot hypocotyls

1990 ◽  
Vol 68 (6) ◽  
pp. 1265-1270 ◽  
Author(s):  
Gilles Gay
Keyword(s):  
Acetic Acid ◽  
Ectomycorrhizal Fungi ◽  
Culture Filtrate ◽  
Root Formation ◽  
Pinus Halepensis ◽  
Hormonal Treatment ◽  
Adventitious Root Formation ◽  
Ectomycorrhizal Fungus ◽  
Indole 3 Acetic Acid

The effect of the ectomycorrhizal fungus Hebeloma hiemale and of its culture filtrate on in vitro rooting of Pinus halepensis derooted shoot hypocotyls was studied in an attempt to determine if ectomycorrhizal fungi could enhance adventitious root formation in gymnosperms. Pinus halepensis hypocotyls did not root in the absence of hormonal treatment, whereas the rooting percentage was 87.3% in the presence of 5 μM indole-3-acetic acid (IAA). In the presence of tryptophan, which is a precursor of IAA, H. hiemale strongly enhanced rooting of hypocotyls cultivated in the absence of any hormonal treatment. In the presence of 0.1 mM tryptophan, the rooting percentage of the inoculated hypocotyls was 96.6%, whereas it was only 7.6% in the absence of the fungus. Hebeloma hiemale culture filtrate obtained in the absence of tryptophan did not contain IAA and did not stimulate rooting of the hypocotyls. In contrast, a culture filtrate obtained in the presence of tryptophan contained IAA; an ethyl acetate extract from this filtrate allowed 100% rooting. Different fractions were isolated by preparative thin-layer chromatography from the IAA-containing filtrate and studied for their effect on rooting. It was demonstrated that IAA was responsible for the rhizogenic activity of H. hiemale. These results suggest that ectomycorrhizal fungi which rapidly metabolize exogenously supplied tryptophan to IAA could be a suitable tool to enhance in vitro rooting of micropropagated gymnosperms. Key words: ectomycorrhizal fungus, indole-3-acetic acid, rooting, shoot hypocotyl, Hebeloma hiemale, Pinus halepensis.

The Shikimate Pathway: Biosynthesis of Phenolic Products from Shikimic Acid

2016 ◽  
Author(s):  
Gary W. Morrow
Keyword(s):  
Amino Acids ◽  
Secondary Metabolites ◽  
Shikimic Acid ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Essential Amino Acids ◽  
Bimolecular Reaction ◽  
Pentose Phosphate ◽  
Chemotherapy Agent ◽  
Acid Pathway

Like other amino acids, the aromatic amino acids phenylalanine, tyrosine, and tryptophan are vitally important for protein synthesis in all organisms. However, while animals can synthesize tyrosine via oxidation of phenylalanine, they can synthesize neither phenylalanine itself nor tryptophan and so these essential amino acids must be obtained in the diet, usually from plant material. Though many other investigators made significant contributions in this area over the years, it was Bernhard Davis in the early 1950s whose use of mutant stains of Escherichia coli led to a full understanding of the so-called shikimic acid pathway that is used by plants and also by some microorganisms for the biosynthesis of these essential amino acids. The pathway is almost completely devoted to their synthesis for protein production in bacteria, while in plants the pathway extends their use to the construction of a wide array of secondary metabolites, many of which are valuable medicinal agents. These secondary metabolites range from simple and familiar compounds such as vanillin (vanilla flavor and fragrance) and eugenol (oil of clove, a useful dental anesthetic) to more complex structures such as pinoresinol, a common plant biochemical, and podophyllotoxin, a powerful cancer chemotherapy agent. Earlier in Chapter 3, we encountered two important intermediates, erythrose-4-phosphate and phosphoenolpyruvate (PEP), each of which was derived from a different pathway utilized in carbohydrate metabolism. Erythrose-4-P was an intermediate in one of the steps of the pentose phosphate pathway while hydrolysis of PEP to pyruvic acid was the final step in glycolysis. These two simple intermediates provide the seven carbon atoms required for construction of shikimic acid itself. The two are linked to one another via a sequence of enzyme-mediated aldol-type reactions, the first being a bimolecular reaction and the second an intramolecular variant that ultimately leads to a cyclic precursor of shikimic acid known as 3-dehydroquinic acid as shown in Fig. 6.3. Subsequent dehydration of 3-dehydroquinic acid leads to 3-dehydroshikimic acid which then leads directly to shikimic acid via NADPH reduction.

scholarly journals The ectopic expression of Arabidopsis glucosyltransferase UGT74D1 affects leaf positioning through modulating indole-3-acetic acid homeostasis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shanghui Jin ◽  
Bingkai Hou ◽  
Guizhi Zhang
Keyword(s):  
Acetic Acid ◽  
Ectopic Expression ◽  
Leaf Angle ◽  
Kinase Substrate ◽  
Auxin Distribution ◽  
Leaf Tissues ◽  
Photosynthesis Efficiency ◽  
Indole 3 Acetic Acid

AbstractLeaf angle is an important agronomic trait affecting photosynthesis efficiency and crop yield. Although the mechanisms involved in the leaf angle control are intensively studied in monocots, factors contribute to the leaf angle in dicots are largely unknown. In this article, we explored the physiological roles of an Arabidopsis glucosyltransferase, UGT74D1, which have been proved to be indole-3-acetic acid (IAA) glucosyltransferase in vitro. We found that UGT74D1 possessed the enzymatic activity toward IAA glucosylation in vivo and its expression was induced by auxins. The ectopically expressed UGT74D1 obviously reduced the leaf angle with an altered IAA level, auxin distribution and cell size in leaf tissues. The expression of several key genes involved in the leaf shaping and leaf positioning, including PHYTOCHROME KINASE SUBSTRATE (PKS) genes and TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) genes, were dramatically changed by ectopic expression of UGT74D1. In addition, clear transcription changes of YUCCA genes and other auxin related genes can be observed in overexpression lines. Taken together, our data indicate that glucosyltransferase UGT74D1 could affect leaf positioning through modulating auxin homeostasis and regulating transcription of PKS and TCP genes, suggesting a potential new role of UGT74D1 in regulation of leaf angle in dicot Arabidopsis.

scholarly journals Effects of Variations in Hormonal Treatments Upon In vitro Regeneration Potential in Embryo Explants of Arenga pinnata

2021 ◽  
Vol 17 (5) ◽  
pp. 495-503
Author(s):  
Shamsiah Abdullah ◽  
Siti Nurain Roslan
Keyword(s):  
Acetic Acid ◽  
In Vitro Regeneration ◽  
Hormonal Treatment ◽  
Height Increment ◽  
Regeneration Potential ◽  
In Vitro Method ◽  
Indole 3 Acetic Acid ◽  
Hormonal Treatments

One of the challenges related to propagation of Arenga pinnata is its lengthy period of seed dormancy. In this study, in vitro regeneration was carried out to determine the effect of hormonal treatment on the embryo explant of Arenga pinnata. Embryos were surface sterilized and cultured into different media supplemented with various hormones concentrations and combinations. Each treatment contained of Kinetin (KN) hormone (1.0, 2.0, and 3.0 mg/l) and in combination with indole-3-acetic acid (IAA) of 0.1, 0.2, 0.3 mg/l. The height of plumule and length of radical was observed and recorded. Treatment 8 (3 mg/ml KN + 0.1 mg/ml IAA) showed 59.09% in plumule height increment while treatment 4 (1 mg/ml KN + 0.3 mg/ml IAA) showed the highest radical increments with 93.62%. The knowledge gained in this study consequently helps us to better understand the role of KN and IAA in the in vitro regeneration protocol. Since in vitro method able to produce higher number of in vitro seedlings at one time, it is important to establish the in vitro regeneration protocol for this plant.

scholarly journals Adaptation of bacteria to glyphosate: a microevolutionary perspective of the enzyme 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase

2020 ◽  
Author(s):  
Miia J. Rainio ◽  
Suvi Ruuskanen ◽  
Marjo Helander ◽  
Kari Saikkonen ◽  
Irma Saloniemi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Active Site ◽  
Shikimate Pathway ◽  
Aromatic Amino Acids ◽  
Ecosystem Functions ◽  
Epsp Synthase

ABSTRACTGlyphosate is the leading herbicide worldwide, but it also affects prokaryotes because it targets the central enzyme (EPSPS) of the shikimate pathway in the synthesis of the three essential aromatic amino acids in autotrophs. Our results reveal that bacteria easily become resistant to glyphosate through changes in the EPSPS active site. This indicates the importance of examining how glyphosate affects microbe-mediated ecosystem functions and human microbiomes.

Characterization of the indole-3-acetic acid (IAA) biosynthetic pathway in an epiphytic strain of Erwinia herbicola and IAA production in vitro

1996 ◽  
Vol 42 (6) ◽  
pp. 586-592 ◽  
Author(s):  
M. Brandi ◽  
E. M. Clark ◽  
S. E. Lindow
Keyword(s):  
Acetic Acid ◽  
Pseudomonas Syringae ◽  
Pyruvic Acid ◽  
Enzyme Assays ◽  
Erwinia Herbicola ◽  
Iaa Production ◽  
Acid Pathway ◽  
Culture Supernatants ◽  
Indole 3 Acetic Acid

An epiphytic strain of Erwinia herbicola (strain 299R) synthesized indole-3-acetic acid (IAA) from indole-3-pyruvic acid and indole-3-acetaldehyde, but not from indole-3-acetamide and other intermediates of various IAA biosynthetic pathways in enzyme assays. TLC, HPLC, and GC–MS analyses revealed the presence of indole-3-pyruvic acid, indole-3-ethanol, and IAA in culture supernatants of strain 299R. Indole-3-acetaldehyde was detected in enzyme assays. Furthermore, strain 299R genomic DNA shared no homology with the iaaM and iaaH genes from Pseudomonas syringae pv. savastanoi, even in Southern hybridizations performed under low-stringency conditions. These observations strongly suggest that unlike gall-forming bacteria which can synthesize IAA by indole-3-acetamide, the indole-3-pyruvic acid pathway is the primary route for IAA biosynthesis in this plant-associated strain. IAA synthesis in tryptophan-supplemented cultures of strain 299R was over 10-fold higher under nitrogen-limiting conditions, indicating a possible role for IAA production by bacterial epiphytes in the acquisition of nutrients during growth in their natural habitat.Key words: indole-3-acetic acid, Erwinia, tryptophan, indole-3-pyruvic acid, nitrogen.

Hydrogen Peroxide Might Bleach Natural Dentin by Oxidizing Phosphoprotein

2018 ◽  
Vol 97 (12) ◽  
pp. 1339-1345 ◽  
Author(s):  
T. Jiang ◽  
Y.R. Guo ◽  
X.W. Feng ◽  
Y. Sa ◽  
X. Yang ◽  
...  
Keyword(s):  
Amino Acids ◽  
Hydrogen Peroxide ◽  
Acetic Acid ◽  
Aromatic Amino Acids ◽  
Disodium Salt ◽  
Tooth Bleaching ◽  
Distilled Water ◽  
Fluorescent Properties ◽  
Fluorescent Intensity ◽  
Tooth Color

Recent studies suggested that bleaching agents may whiten teeth by oxidizing the fluorescent materials, which are the proteins located in the organic-inorganic interface. Therefore, we postulated that fluorescence of dentin came from dentin phosphoprotein (DPP) and that bleaching agents might bleach dentin by oxidizing DPP. Fifty-six specimens were randomly divided into 4 groups and exposed to distilled water, hydrogen peroxide (HP), ethylenediamine tetraacetic acid disodium salt (EDTA), and acetic acid for 24 h. After measuring the organic and inorganic components, fluorescence, and color characteristics of dentin before and after exposure, we found that when DPP was removed from dentin by EDTA, fluorescent intensity declined proportionally with the reduction in Raman relative intensity, and dentin was whitened considerably, with an Δ E value 6 times higher than that of the distilled water group. On the contrary, due to the incapability of acetic acid to dissolve DPP during decalcification, fluorescent intensity values and tooth color remained nearly unchanged after exposure to acetic acid. Dentin exposed to neutral HP showed no obvious morphologic and organic/inorganic component changes except for the destruction of DPP. Similarly, dramatically decreased fluorescent intensity and lightened color were found in the HP group. Moreover, DPP solution of the HP group exhibited decreased ultraviolet absorbance, especially between 250 and 300 nm, which arose from aromatic amino acids. The results indicated that DPP was responsible for the fluorescent properties of dentin and that HP might bleach dentin by the oxidization of aromatic amino acids in DPP. These findings are of great significance in promoting our further understanding of the mechanism of tooth bleaching and the fluorescent property of normal dentin.

scholarly journals In vitro callus induction of gerbera from leaf explant

2020 ◽  
Vol 8 (1) ◽  
pp. 1
Author(s):  
Sadia Afrin Jui ◽  
Md. Mijanur Rahman Rajib ◽  
M. Mofazzal Hossain ◽  
Sharmila Rani Mallik ◽  
Iffat Jahan Nur ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Growth Regulators ◽  
Callus Induction ◽  
Leaf Explants ◽  
Leaf Explant ◽  
Naphthalene Acetic Acid ◽  
Dichlorophenoxyacetic Acid ◽  
Ms Medium ◽  
Indole 3 Acetic Acid

The experiment was designed to evaluate the effect of growth regulators on leaf explant of Gerbera for callus induction. Various kinds of plant growth regulators such as 6-Benzylaminopurine (BAP), α-Naphthalene acetic acid (NAA), 2, 4-Dichlorophenoxyacetic acid (2, 4-D), Indole-3-acetic acid (IAA) were used to initiate cultures. These were added to Murashige and Skoog medium in different combinations and concentrations. Leaf explants cultured on MS medium supplemented with BAP+ 2, 4-D+ IAA in T4 treatment & BAP+ 2,4-D in T5 treatment showed the best results for callus induction. On the other hand callus was induced early in the combination of BA+ 2,4-D + IAA hormone in T5, T9 & T8 treatment respectively. The rate of callus induction was very low in BA + NAA combinations but it was much earlier.   

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