Indolyl-3-acetic Acid and Ethylene Levels in Ripening Apple Fruits

Indolyl-3-acetic acid (IAA) levels in apple (Malus domesticaBorkh.) fruits were determined fluorimetrically after formationof 2-methylindolo--pyrone in purified extracts. The propertiesof the fluorescent products in apple samples were identicalwith those of authentic IAA. The assays were performed on samplesof cortex with or without peel from the varieties James Grieveand Worcester Pearmain during the last 50—70 d of theirdevelopment on the tree. At the same time the ethylene concentrationin the core cavity of the fruits was measured as a guide tothe progress of ripening. IAA concentration showed a 3—4-foldincrease prior to the rapid rise in ethylene concentration butfell to about its original level as this rise occurred. IAAwas also measured in the seeds of James Grieve apples, whereit rose to a peak concentration and declined before the peakobserved in the fleshy tissue of the fruit. IAA in the seedsincreased markedly after 15 d storage of the fruit harvested136 d after full bloom.     

Bacterial Blister Bark of Apple Trees in Italy

At the beginning of spring 1996, raised, brown areas along the bark of trunk and twigs were observed on young apple trees in Piedmont (northern Italy). In many cases the epidermis flaked off. Longitudinal cracks accompanied by necrosis of the tissues beneath the bark were also observed. In one orchard the disease caused the death of 2500 trees. Biochemical, nutritional and pathogenicity tests, as well as the comparison of whole-cell protein profiles of the isolates with type-strains, indicated that Pseudomonas syringae pv. syringae was the causal agent of the disease. Bacterial blister bark remains a threat for apple cultivation also in Italy, especially in orchards planted in sandy soils.     

Transport of Indole-3-Acetic Acid during Gravitropism in Intact Maize Coleoptiles

We have investigated the transport of tritiated indole-3-acetic acid (IAA) in intact, red light-grown maize (Zea mays) coleoptiles during gravitropic induction and the subsequent development of curvature. This auxin is transported down the length of gravistimulated coleoptiles at a rate comparable to that in normal, upright plants. Transport is initially symmetrical across the coleoptile, but between 30 and 40 minutes after plants are turned horizontal a lateral redistribution of the IAA already present in the transport stream occurs. By 60 minutes after the beginning of the gravitropic stimulus, the ratio of tritiated tracer auxin in the lower half with respect to the upper half is approximately 2:1. The redistribution of growth that causes gravitropic curvature follows the IAA redistribution by 5 or 10 minutes at the minimum in most regions of the coleoptile. Immobilization of tracer auxin from the transport stream during gravitropism was not detectable in the most apical 10 millimeters. Previous reports have shown that in intact, red light-grown maize coleoptiles, endogenous auxin is limiting for growth, the tissue is linearly responsive to linearly increasing concentrations of small amounts of added auxin, and the lag time for the stimulation of straight growth by added IAA is approximately 8 or 9 minutes (TI Baskin, M Iino, PB Green, WR Briggs [1985] Plant Cell Environ 8: 595-603; TI Baskin, WR Briggs, M Iino [1986] Plant Physiol 81: 306-309). We conclude that redistribution of IAA in the transport stream occurs in maize coleoptiles during gravitropism, and is sufficient in degree and timing to be the immediate cause of gravitropic curvature.     

Oxidation of Indole-3-Acetic Acid to Oxindole-3-Acetic Acid by an Enzyme Preparation from Zea mays

Indole-3-acetic acid is oxidized to oxindole-3-acetic acid by Zea mays tissue extracts. Shoot, root, and endosperm tissues have enzyme activities of 1 to 10 picomoles per hour per milligram protein. The enzyme is heat labile, is soluble, and requires oxygen for activity. Cofactors of mixed function oxygenase, peroxidase, and intermolecular dioxygenase are not stimulatory to enzymic activity. A heat-stable, detergent-extractable component from corn enhances enzyme activity 6- to 10-fold. This is the first demonstration of the in vitro enzymic oxidation of indole-3-acetic acid to oxindole-3-acetic acid in higher plants.     

Dioxindole-3-Acetic Acid Conjugates Formation from Indole-3-Acetylaspartic Acid in Vicia Seedlings

When indole-3-acetic acid (IAA) is applied to the cotyledonsof broad bean seedlings (Vicia faba L. cv Chukyo), the majormetabolites found in the roots are 3-(O-ß-glucosyl)-2-indoIone-3-acetylaspartic acid (Glc-DIA-Asp) and 3-hydroxy-2-indolone-3-acetylasparticacid (DIA-Asp). In this report, the metabolic pathway from IAAto the two dioxindole-3-acetic acid (DIA) conjugates was investigatedby using [¹⁴C]IAA, [¹⁴C]DIA, [¹⁴C]indole-3-acetylaspartic acid(IAA-Asp), and [¹⁴C]IAA-[³H]Asp. The precursor of DIA-Asp wasfound to be IAA-Asp but not DIA. Incorporation of the doublelabeled IAA-Asp into the DIA conjugates demonstrated that hydrolysisof IAA-Asp was not involved in the formation of the DIA conjugates.DIA-Asp was further metabolized to Glc-DIA-Asp in the cotyledons,while formation of Glc-DIA-Asp in the roots was very low. Glc-DIA-Aspformed in the cotyledons was transported to the roots. (Received April 21, 1986; Accepted September 10, 1986)     

Determination of 1-Methylimidazole-4-Acetic Acid in Brain Tissue from Rat and Mouse

The concentration of the histamine metabolite 1-methylimidazole-4-acetic acid was determined in brain tissue from rat and mouse with a gas chromatographic-mass spectrometric method. Mouse brain contained 1.7-3.2 nmol/g, depending on the strain. The concentration in cerebrum from Sprague-Dawley rats was 1.2 nmol/g, whereas cerebellum contained 0.24 nmol/g. The concentration of tele-methylhistamine in mouse brain was 1.4-2.2 nmol/g. The concentration of 1-methylimidazole-4-acetic acid in rat brain after death did not change significantly during 2 h at room temperature.     

Levels of Indole-3-Acetic Acid in Lemna gibba G-3 and in a Large Lemna Mutant Regenerated from Tissue Culture

Large changes in indole-3-acetic acid (IAA) levels occur during growth of Lemna gibba G-3 in sterile culture. The levels of IAA were measured in plants during a 45 day growth cycle using HPLC and isotope dilution analysis followed by selected ion current monitoring GC-MS analysis with ¹³C₆-IAA as the internal standard. Even though the rate of plant growth remained constant over the entire growth period, IAA levels ranged from a high of 222 to a low of 6 nanograms per gram fresh weight. A Lemna mutant (jsR₁) which has a giant phenotype was obtained by regeneration from primary callus cultures. Microspectrofluorometry of diamidino-2-phenylindole stained cells showed that jsR₁ has the same amount of DNA per nucleus as the parent line (PL). All jsR₁ cell types measured are about 1.5 times larger than in PL. The endogenous levels of IAA per gram fresh weight were higher in jsR₁ at several stages of the plant culture cycle as compared to PL. This difference ranged from 1.2 to over 100 times as much. While PL showed only one high peak at day 9, jsR₁ had IAA levels of 480 and 680 nanograms per gram fresh weight at days 9 and 45, respectively. Throughout the midculture stage of the growth cycle (20-28 days) both jsR₁ and PL had IAA levels in the range of 9 to 14 nanograms per gram fresh weight. In contrast to PL, at day 45, jsR₁ had no detectable ester or amide conjugates of IAA. These changes in IAA levels were determined in sterile plant cultures and thus cannot be attributed to bacterial or fungal activity.     

Metabolism of Indole-3-Acetic Acid: III. Identification of Metabolites Isolated from Crown Gall Callus Tissue

The metabolism of labeled indole-3-acetic acid (IAA-2-¹⁴C) was investigated in Parthenocissus tricuspidata crown gall callus tissue. After 48 hours incubation, 85 to 90% of the supplied IAA was taken up by the tissue, and of that taken up, about 45% was conjugated with five amino acids. The conjugates found were aspartic and glutamic acid (minor ones) as well as glycine, alanine, and valine (major ones). The last four are being reported for the first time as metabolites of IAA. These conjugates were identified through their chromatographic properties, hydrolysis products, and their mass spectra. The possible significance of these amino acid conjugates is discussed.     

Polar Transport of Indole-3-Acetic Acid in Relation to Rooting in Carnation Cuttings: Influence of Cold Storage Duration and Cultivar

The influence of cold storage of cuttings on the transport and metabolism of indole-3-acetic acid (IAA) and the rooting were studied in two carnation (Dianthus caryophyllus L.) cultivars (Oriana and Elsy), which are known to exhibit very distinct rooting characteristics. The percentage of rooting at 11 d after planting increased with the storage period particularly in Oriana, but the values in Elsy were higher than in Oriana. Auxin transport was measured by applying ³H-IAA to stem sections. Irrespective of the section localization, the oldest node (node) or the basal internode (base), the transport increased as the storage period increased from 2 to 12 weeks in Oriana and from 2 to 8 weeks in Elsy cuttings. The auxin transport rate was higher in bases than in nodes and also in Elsy than in Oriana at a given storage period. IAA oxidation and hydrolyzation of IAA conjugates (determined by extracting the sections with acetonitrile and NaOH once the basipetal IAA movement ceased after a 24 h transport period) showed a negative, highly significant correlation with the amount of IAA transported. Although the rooting percentage and IAA transport were higher in Elsy than in Oriana, the differences in rooting between the cultivars could not be explained solely by differences in IAA transport.     

Measurement of the Rates of Oxindole-3-Acetic Acid Turnover, and Indole-3-Acetic Acid Oxidation in Zea mays Seedlings

Nonhcbcl, H. M. 1986. Measurement of the rates of oxindole-3-aceticacid turnover and indole-3-acetic acid oxidation in Zea maysseedlings.—J. exp. Bat. 37: 1691–1697. Oxindole-3-acetic acid is the pnncipal catabolite of indole-3-aceticacid in Zea mays seedlings. In this paper measurements of theturnover of oxindole-3-acetic acid are presented and used tocalculate the rate of indole-3-acetic acid oxidation. [³H]Oxindolc-3-acetic acid was applied to the endosperm of Zeamays seedlings and allowed to equilibrate for 24 h before thestart of the experiment. The subsequent decrease in its specificactivity was used to calculate the turnover rate. The averagehalf-life of oxindole-3-acetic acid in the shoots was foundto be 30 h while that in the kernels had an average half-lifeof 35 h. Using previously published values of the pool sizesof oxindole-3-acetic acid in shoots and kernels from seedlingsof the same age and variety, and grown under the same conditions,the rate of indole-3-acetic acid oxidation was calculated tobe I-I pmol plant^–1 h^–1 in the shoots and 7·1pmol plant^–1 h^–1 in the kernels. Key words: Oxindole-3-acetic acid, indole-3-acetic acid, turnover, Zea mays     

Metabolism of Indole-3-Acetic Acid in Arabidopsis

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.The plant hormone IAA is an important signal molecule in the regulation of plant development. Its central role as a growth regulator makes it necessary for the plant to have mechanisms that strictly control its concentration. The hormone is believed to be active primarily as the free acid, and endogenous levels are controlled in vivo by processes such as synthesis, oxidation, and conjugation. IAA has been shown to form conjugates with sugars, amino acids, and small peptides. Conjugates are believed to be involved in IAA transport, in the storage of IAA for subsequent use, in the homeostatic control of the pool of the free hormone, and as a first step in the catabolic pathways (Cohen and Bandurski, 1978; Nowacki and Bandurski, 1980; Tuominen et al., 1994; Östin et al., 1995; Normanly, 1997). It is generally accepted that in some species conjugated IAA is the major source of free IAA during the initial stages of seed germination (Ueda and Bandurski, 1969; Sandberg et al., 1987; Bialek and Cohen, 1989), and there is also evidence that in some plants (but not all; see Bialek et al., 1992), the young seedling is entirely dependent on the release of free IAA from conjugated pools until the plant itself is capable of de novo synthesis (Epstein et al., 1980; Sandberg et al., 1987).The function of conjugated IAA during vegetative growth is somewhat less clear. It has been shown that conjugated IAA constitutes as much as 90% of the total IAA in the plant during vegetative growth (Normanly, 1997). However, the role of the IAA conjugates at this stage of the plant''s life cycle remains unknown. Analysis of endogenous IAA conjugates in vegetative tissues has revealed the presence of a variety of different compounds, including indole-3-acetyl-inositol, indole-3-acetyl-Ala, IAAsp, and IAGlu (Anderson and Sandberg, 1982; Cohen and Baldi, 1983; Chisnell, 1984; Cohen and Ernstsen, 1991; Östin et al., 1992). Studies of vegetative tissues have indicated that IAAsp, one of the major conjugates in many plants, is the first intermediate in an irreversible deactivation pathway (Tsurumi and Wada, 1986; Tuominen et al., 1994; Östin, 1995). Another mechanism that is believed to be involved in the homeostatic control of the IAA pool is catabolism by direct oxidation of IAA to OxIAA, which has been shown to occur in several plant species (Reinecke and Bandurski, 1983; Ernstsen et al., 1987).One area in the study of IAA metabolism in which our knowledge is increasing is the analysis of the homeostatic controls of IAA levels in plants. It has been possible, for instance, to increase the levels of IAA in transgenic plants expressing iaaM and iaaH genes from Agrobacterium tumefaciens. Analysis of these transgenic plants has indicated that plants have several pathways that can compensate for the increased production of IAA (Klee et al., 1987; Sitbon, 1992). It is expected that future studies using now-available genes will provide further insight into IAA metabolism. For example, a gene in maize encoding IAA-Glc synthetase has been identified, and several genes (including ILR1, which may be involved in hydrolysis of the indole-3-acetyl-Leu conjugate) have been cloned from Arabidopsis (Szerszen et al., 1994; Bartel and Fink, 1995). Furthermore, Chou et al. (1996) identified a gene that hydrolyzes the conjugate IAAsp to free IAA in the bacterium Enterobacter aggloremans.Because of its small genome size, rapid life cycle, and the ease of obtaining mutants, Arabidopsis is increasingly used as a genetic model system to investigate various aspects of plant growth and development. IAA signal transduction is also being investigated intensively in Arabidopsis in many laboratories (Leyser, 1997). Mutants with altered responses to externally added auxins or IAA conjugates have been identified in Arabidopsis. The identified mutants are either signal transduction mutants such as axr1-4 (Lincoln et al., 1990), or have mutations in genes involved in auxin uptake or transport, such as aux1 and pin1 (Okada et al., 1991; Bennett et al., 1996). A few mutants that are unable to regulate IAA levels or are unable to hydrolyze IAA conjugates, sur1-2 and ilr1, respectively, have also been identified (Bartel and Fink, 1995; Boerjan et al., 1995). To our knowledge, no mutant that is auxotrophic for IAA has been identified to date, which may reflect the redundancy in IAA biosynthetic pathways or the lethality of such mutants.In spite of the work reported thus far, many aspects of the metabolism of IAA in Arabidopsis require further investigation, because few details of the processes involved in IAA regulation are known. This lack of knowledge puts severe constraints on genetic analysis of IAA metabolism in Arabidopsis. For example, it is essential to have prior knowledge of IAA metabolism to devise novel and relevant screens with which to identify mutants of IAA metabolism. We have sought to address this issue by identifying the metabolic pathways involved in catabolism and conjugation under conditions that minimally perturb physiological processes. In this investigation we studied the conjugation and catabolic pattern of IAA by supplying relatively low levels of labeled IAA and identifying the catabolites and conjugates by MS. Different feeding systems were tested to optimize the application of IAA and to avoid irregularities in metabolism attributable to culturing, feeding conditions, or microbial activity. It is well documented that IAA metabolism is altered according to the amount of exogenous auxin applied; therefore, we placed special emphasis on distinguishing between catabolic routes that occur at near-physiological concentrations and those that occur at the high auxin concentrations commonly used in mutant screens.     

The Stimulatory Effect of Indole-3-Acetic Acid on the Uptake of Amino-Acids by Tissue 1Helianthus annuus

Indole-3-acetic acid was observed to bring about a prompt andmarked increase in the amount of ¹⁴C accumulated by segmentsof sunflower hypocotyl from solutions of labelled glutamic acid,glycine, and lysine. The curve relating magnitude of effectto indole-3-acetic acid concentration followed the comparablecurves for water uptake and extension growth. The accumulation of ¹⁴C was related to the external concentrationof glutamic acid by a curve which departed only slightly fromlinearity. The percentage increase in ¹⁴C accumulation broughtabout by auxin did not decline to any appreciable extent withincreasing external concentration of glutamic acid. Under nitrogen the amount of ¹⁴C taken up from solutions oflabelled glutamic acid in 1·75 hour was cut down by approximatelyone-third, and the auxin effect was abolished. The Q₁₀ for ¹⁴Caccumulation between 16° C. and 26° C. was 1·2in the absence of indole-3-acetic acid, and was 1·3 inits presence. When net water uptake was eliminated by the addition of mannitolto the external solution, ¹⁴C accumulation in auxin-free mediawas not depressed. The percentage increase in ¹⁴C accumulationbrought about by auxin, however, was markedly reduced. The fate of the ¹⁴C accumulated was investigated by means ofchromatography on resin columns and on filter paper. About 30–40percent, of the ¹⁴C was in the form of glutamic acid after approximatelya hours' treatment. No marked difference in the level of glutamicacid was observed between auxin-treated and control segments.The effect of auxin was more evident on the amounts of otherradioactive derivatives, as yet unidentified. It was observed that, not only was the amount of CO₂ evolvedin respiration higher in the presence of indole-3-acetic acid,but that this CO₂ was richer in ¹⁴C, i.e. in auxin-treated tissueglutamic acid formed a larger proportion of the substrate respired. The possible implications of these observations are discussed.It is pointed out that indole-3-acetic acid may have achievedits effect by stimulating a transfer process, by lessening adiffusion resistance, or by promoting a process or processeswhich, by removing free amino-acids within the cell, maintainan inward diffusion gradient.     

Tryptophan Biosynthesis from Indole-3-Acetic Acid by Anaerobic Bacteria from the Rumen

Microbes in ruminal contents incorporated (14)C into cells when they were incubated in vitro in the presence of [(14)C]carboxyl-labeled indole-3-acetic acid (IAA). Most of the cellular (14)C was found to be in tryptophan from the protein fractions of the cells. Pure cultures of several important ruminal species did not incorporate labeled IAA, but all four strains of Ruminococcus albus tested utilized IAA for tryptophan synthesis. R. albus did not incorporate (14)C into tryptophan during growth in medium containing either labeled serine or labeled shikimic acid. The mechanism of tryptophan biosynthesis from IAA is not known but appears to be different from any described biosynthetic pathway. We propose that a reductive carboxylation, perhaps involving a low-potential electron donor such as ferredoxin, is involved.     

Regulation of Auxin Homeostasis and Gradients in Arabidopsis Roots through the Formation of the Indole-3-Acetic Acid Catabolite 2-Oxindole-3-Acetic Acid

The native auxin, indole-3-acetic acid (IAA), is a major regulator of plant growth and development. Its nonuniform distribution between cells and tissues underlies the spatiotemporal coordination of many developmental events and responses to environmental stimuli. The regulation of auxin gradients and the formation of auxin maxima/minima most likely involve the regulation of both metabolic and transport processes. In this article, we have demonstrated that 2-oxindole-3-acetic acid (oxIAA) is a major primary IAA catabolite formed in Arabidopsis thaliana root tissues. OxIAA had little biological activity and was formed rapidly and irreversibly in response to increases in auxin levels. We further showed that there is cell type–specific regulation of oxIAA levels in the Arabidopsis root apex. We propose that oxIAA is an important element in the regulation of output from auxin gradients and, therefore, in the regulation of auxin homeostasis and response mechanisms.     

Influence of 5-Methyltryptophan-Resistant Bradyrhizobium japonicum on Soybean Root Nodule Indole-3-Acetic Acid Content

Bradyrhizobium japonicum mutants resistant to 5-methyltryptophan were isolated. Some of these mutants were found to accumulate indole-3-acetic acid (IAA) and tryptophan in culture. In greenhouse studies, nodules from control plants inoculated with wild-type bradyrhizobia contained 0.04, 0.10, and 0.58 μg of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules⁻¹, respectively. Nodules from plants inoculated with 5-methyltryptophan-resistant bradyrhizobia contained 0.94, 1.30, and 10.6 μg of free, ester-linked, and peptidyl IAA g (fresh weight) of nodules⁻¹, respectively. This manyfold increase in nodule IAA content indicates that the Bradyrhizobium inoculum can have a considerable influence on the endogenous IAA level of the nodule. Further, these data imply that much of the IAA that accumulated in the high-IAA-containing nodules was of bacterial rather than plant origin. These high-IAA-producing 5-methyltryptophan-resistant bacteria were poor symbiotic nitrogen fixers. Plants inoculated with these bacteria had a lower nodule mass and fixed less nitrogen per gram of nodule than did plants inoculated with wild-type bacteria.     

Metabolism of Indole-3-Acetic Acid: II. Oxindole Pathway in Parthenocissus tricuspidata Crown-Gall Tissue Cultures

An indoleacetic acid oxidase preparation from an acetone powder of Parthenocissus tricuspidata crown-gall tissue has been examined. An intermediate in the reaction is 3-hydroxymethyloxindole and nonenzymic conversion of it to 3-methyleneoxindole was observed. Neither reaction mixtures nor 3-methyleneoxindole have any auxin-like activity in Avena or wheat coleoptile bioassays. In vivo studies show that although 53% decarboxylation of indoleacetic acid was observed in 48 hours, only a small amount of 3-methyloxindole could be recovered from the medium. The other decarboxylated products remain to be identified but are not 3-hydroxymethyloxindole or 3-methyleneoxindole.     

Changes in the Content of Indole-3-Acetic Acid and Cytokinins in Spruce, Fir and Oak Trees after Herbicide Treatment

Treatment of spruce, fir and oak trees with herbicides, which may be one of the forest damage inducing agents, caused pronounced changes in the contents and distribution of indole-3-acetic acid (IAA) and cytokinins (CKs) one year after treatment, i.e. at the time of the first microscopically visible damage in treated trees. In Picea pungens IAA content increased in the terminal buds by about 105 % and in the apical buds of the first order branches by 220 %. The same was true for young sprouts of Abies nordmanniana, while in leaves of oak trees IAA content was decreased by 15 % after glyphosate treatment and by 30 % after 2,4-dichlorophenoxyacetic acid (2,4-D) treatment. Another striking feature was a significantly decreased content of IAA in the lower parts of roots in Picea pungens (50 % of the control), which is accompanied by an increase in IAA content in the middle part of the roots (130 %). On the other hand, the IAA content of both sprouts and roots of A. nordmanniana was significantly increased after herbicide treatment.In P. pungens, the content of free cytokinins (sum of zeatin, zeatin riboside, isopentenyladenine and isopentenyladenosine) decreased due to herbicide treatment. The strongest decrease was seen in roots, especially in their upper and middle parts (the average reduction of cytokinin content in roots was 63 %). In the above-ground organs the reduction was seen namely for isopentenyladenine and isopentenyladenosine, while the abundance of zeatin riboside was, on the other hand, higher in treated plants. In Quercus robur leaves, the total content of cytokinins also decreased, namely after glyphosate treatment. In consequence of these changes, CK/IAA ratio decreased pronouncedly in all organs of herbicide-treated trees, with the exception of oak leaves treated by 2,4-D.     

Identification of Indole-3-Acetic Acid in the Basidiomycete Schizophyllum commune

Indole-3-acetic acid (IAA) was detected in the ether extracts of culture filtrates of indigotin-producing strains of the basidiomycete Schizophyllum commune. Several solvents, known to give distinctly different R_F values for IAA, and 3 location reagents gave identical results with synthetic IAA and IAA found in the extract. Confirmation was obtained by the Avena straight growth test, split pea test, and ultraviolet absorption spectrum.