• Mycobiology
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• v.47 no.3
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• pp.292-300
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• 2019

IAA biosynthetic pathways in a basidiomycetous yeast, Rhodosporidiobolus fluvialis DMKU-CP293, were investigated. The yeast strain showed tryptophan (Trp)-dependent IAA biosynthesis when grown in tryptophan supplemented mineral salt medium. Gas chromatography-mass spectrometry was used to further identify the pathway intermediates of Trpdependent IAA biosynthesis. The results indicated that the main intermediates produced by R. fluvialis DMKU-CP293 were tryptamine (TAM), indole-3-acetic acid (IAA), and tryptophol (TOL), whereas indole-3-pyruvic acid (IPA) was not found. However, supplementation of IPA to the culture medium resulted in IAA peak detection by high-performance liquid chromatography analysis of the culture supernatant. Key enzymes of three IAA biosynthetic routes, i.e., IPA, IAM and TAM were investigated to clarify the IAA biosynthetic pathways of R. fluvialis DMKU-CP293. Results indicated that the activities of tryptophan aminotransferase, tryptophan 2-monooxygenase, and tryptophan decarboxylase were observed in cell crude extract. Overall results suggested that IAA biosynthetic in this yeast strain mainly occurred via the IPA route. Nevertheless, IAM and TAM pathway might be involved in R. fluvialis DMKU-CP293.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.2
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• pp.115-124
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• 1988

This study was carried out to realize the effect of gibberllic acid$(GA_3)$, 1-naphthaleneacetic acid(NAA) and indole-3-acetic acid(IAA) on the biosynthesis of vitamin C. The relation between carbohydrate metabolism and vitamin C production in soybean sprouts was also investigated. Growth, vitamin C content, protein, galactonolactone dehydrogenase(GLD), ribulose diphosphate carboxylase(RuDpCO) and RNA level in the plastid and cytoplasm were determined. The effects of protein and respiratory inhibitors on the growth and vitamin C production were also examined. The most favourable growth of soybean sprouts was observed at the level of NAA $10^{-8}M,\;IAA10^{-6}M\;and\;GA_3\;10^{-5}M$ in the single treatment, respectively, and also favourable at levels of $GA_3\;10^{-5}M+NAA\;10^{-9}M\;and\;GA_3\;10^{-5}M+IAA\;10^{-9}M$ in the case of mixed treatment. The excellent growth was observed at the level IAA $10^{-6}M$ among all the single and mixed treatments. When the soybean sprouts were treated with NAA $10^{-8}M,\;IAA\;10^{-6}M\;GA_3\;10^{-5}M,\;GA_3\;10^{-8}M+IAA\;10^{-6}M,\;and\;GA_3\;10^{-5}M+IAA\;10^{-9}M$, the maximum growth rate was observed at the level of IAA $10^{-6}M$ and the conten of vitamin C was 24.26mg% which was 1.6 times higher than that of the control. RuDpCO was inhibited by the chloramphenicol at the concentration that did not inhibit the growth but the activities of NADP-GDH, GLD and vitamin C content were not affected. These results showed that the biosynthesis of viamin C had nothing to do with the activity of chloroplastic RNA but with cytoplasm. The highest vitamin C content was found at the the level of IAA $10^{-6}M$, where the GLD activity increased up 1.8 times of the control. The concentration of IAA $10^{-6}M$ promoted the biosynthesis of RNa and protein both in chloroplast and cytoplasm, especially in the cytoplasm. Thus it suggeted that IAA affected vitamin C biosynthesis by regulating RNA level in the cytoplasm. 2,4-Dinitrophenol as an uncoupler of oxidative phosphorylation did not inhibit the vitamin C biosynthesis, however, all of the respiratory inhibitors severely inhibited the growth and vitamin C biosynthesis.

• Journal of Applied Biological Chemistry
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• v.43 no.4
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• pp.269-272
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• 2000

The ginseng growth-promoting bacterium Pseudomonas fluorescens KGPP 207 synthesized indole-3- acetic acid (IAA) from L-tryptophan, indole-3-pyruvic acid (IPyA), and indole-3-acetaldehyde (IAAld), but not from indole-3-acetamide (lAM) and other intermediates of various IAA biosynthetic pathways in the experiment with indole compound supplemented cell suspensions. TLC, HPLC, and GC-MS analyses revealed the presence of IPyA, indole-3-ethanol, indole-3-lactic acid and its methyl ester, IAA and its methyl, and ethyl esters in the culture supernatant of the bacterium. IAAld was detected in the supernatant using sodium bisulfite and TLC. The results indicate that unlike gall-forming bacteria which can synthesize IAA by lAM, the indole-3-pyruvic acid pathway is the route for IAA biosynthesis in this beneficial strain of P. fluorescens.

• Korean Journal of Plant Tissue Culture
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• v.26 no.3
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• pp.171-175
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• 1999

We examined the effects of various basal media and exogenous auxins on the growth and saikosaponin production in hairy root cultures of Bupleurum falcatum. Of the various media tested, 2RCM medium was superior for growth and saikosaponin content, in which saikosaponin a, c, and d was produced, however MS medium was resulted in extremely low level in saikosaponin production. By the treatment of 0.5 mg/L IBA the growth rate was increased by about 60% in 2RCM medium, whereas both IAA and IBA showed a potent inhibition effect in saikosaponin biosynthesis by the treatment of 0.01 mg/L~5mg/L.

• Korean Journal of Organic Agriculture
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• v.14 no.4
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• pp.411-420
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• 2006

Indole-3-acetic acid (IAA) biosynthesis by bacteria occurs widely in rhizospheres. Bacterial species able to synthesize IAAmay be exploited for beneficial interactions in crop management systems. The objective of this study was to determine the response of ivyleaf morningglory (Ipomoea hederacea) seedlings to IAA and to an IAA-producing rhizobacterum, Bradyrhizobium japonicum isolate GD3. IAA solution and isolate GD3 suppression of seedling growth measured as radicle length and biomass depended on IAA concentration. Seedling radicle length was significantly reduced by ca. 29% with more than $1.0{\mu}M$ of IAA solution, compared to the control, 48 h after application. The cell concentration at 50% growth reduction ($GR_{50}$) of the seedling radicle was IAA production by isolate GD3 at $10^{4.82}\;cfu$, the cell concentration for 50% growth reduction ($GR_{50}$) of seedling radicle was 0.24 iM, which was much lower than the IAA solution concentration ($117.48{\mu}M$) required for $GR_{50}$. Therefore, excess IAA production by isolate GD3 may be more detrimental to morningglory radicle growth than standard IAA solution. Results confirmed involvement of IAA in suppressive effects of isolate GD3 on morning-glory seedlings grown in a hydroponic system.

• Journal of Plant Biology
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• v.31 no.3
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• pp.239-247
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• 1988

Spermidine, spermine and IAA promoted an increase in $\beta$-1, 4-endoglucanase activity in hypocotyls of Glycine max. The optimal concentration for the increase of the enzyme activity was 10-6 M for spermidine, 10-8 M for spermine and 10-6 M for IAA. However, IAA had innocuous effect on arginine decarboxylase and ornithine decarboxylase activites, and the content of polyamine. Such cumulative results suggest that the increase in $\beta$-1, 4-endoglucanase activity by IAA is not attributed by the effect on the biosynthesis of polyamine by IAA but spermidine, spermine and IAA induce cell wall loosening and therefore extension growth of cells.

• Journal of Plant Biology
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• v.35 no.4
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• pp.371-383
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• 1992

The effects of IAA $(10^{-3}M)\;an;GA_3\;(2{\times}10^{-8}\;M)$ on the biosynthesis of phospholipids and their fatty acid compositions in chloroplast isolated from Chlorella ellipsidea were analyzed. Growth ratio and the levels of total lipids and phospholipids in whole cell system and chloroplast treated with phytohormones were higher than those of control, and when treated with GAl. phosphatidylcholine content was predominantly higher than that of control. It was showed that in whole cell system the fatty acid utilized for biosynthesis of phopholipids was 27.43% for palmitic acid in control, while that was 20.25% for linolenic acid in treatment with 1M. In treatment with $GA_3$, 23.17% for linolenic acid was used in phospholipid formation. The major fatty acid in the chloroplst system was analyzed to be 35.67% for palmitic acid in control and in treatment with 1M, 24.91% for linolenic acid was used in phospholipid formation, while in treatment with $GA_3$, major fatty acid of phospholipids was 22.80% for linoleic acid.c acid.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.1
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• pp.7-13
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• 2004

Mung beans (Vigna radiata L.) were used to investigate the roles of strontium in hypocolyl elongation under IAA regime during the germination. After imbibition in a medium with or without IAA, $Sr^{2+}$ stimulated IAA oxidation. Three to five fold increasing in IAA oxidase activity seems to be direct evidence of growth inhibition through $Sr^{2+}$. Furthermore, the accumulation of spermidinc and spermine by $Sr^{2+}$ in the range of 1 to 10 mM was observed. Spermidine levels were 2 to 3 fold higher than in control seedling grown without strontium. The increase in polyamine levels was observed on a g fresh weight basis. In conclusion, it was demonstrated that the inhibitory action of $Sr^{2+}$ is closely related with the IAA oxidation and polyamine biosynthesis.

• Korean Journal of Microbiology
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• v.19 no.2
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• pp.52-62
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• 1981

In order to interpret the effect of IAA on the phosphate metabolism and biosynthesis of organic compounds, Saccharomyces uvarum were cultured in the media treated with various concnetration of IAA $(10^{-3}M,\;10^{-5}M,\;10^{-7}M)$. Sampling at the beginning and intervals of culture, yeast cells fractionated were traced the contents of inorganic phosphate and organic compounds of various fractions. 1. Growth of Saccharomyces uvarum were enhanced by IAA $(10^{-3}M,\;10^{-5}M)$ and phosphate contents in DNA and RNA fractions treated with IAA were accelerated 2.3 times and 2 times in comparison with those of control. 2. Amounts of poly-P"A" and poly-p"B" were increased but poly-P"C" decreased during the culture. Therefore, it is considered that poly-P"C" play on most important role as a phosphate pool. 3. It is suggested that because phosphate contents in DNA, protein and lipid fractions increased, inorganic phosphates required phosphates required RNA were transferred from phosphates in cytoplasm, because these increased slowly during the culture. 4. Alkali-labile protein were accelerated by IAA and alkali stable protein only were inhibiction were enhanced by IAA while, ethanol : ether soluble fraction was induced by $10^{-7}M$ IAA in comparison with those control.X> IAA in comparison with those control.

• Applied Biological Chemistry
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• v.33 no.2
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• pp.125-128
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• 1990

Previous work has shown that the levels of free and total IAA and tryptophan decrease on exposing etiolated pea (Pisum sativum L. var. Sparkle) seedlings grown at $25^{\circ}C$ to $5^{\circ}C$ for 3 days, suggesting that low temperature down-regulates the level of endogenous IAA, in part, by reducing tryptophan biosynthesis. To understand, in this study, the effect of low temperature on the regulation of IAA degradation system in etiolated pea seedlings, enzyme levels of IAA degradation system and hydrogen peroxide content were analyzed during and after chilling($5^{\circ}C$) 6-day-old pea seedlings grown at $25^{\circ}C$. The levels of IAA oxidase and peroxidase increased during chilling and gradually restored to the level of control on termination of chilling. Catalase levels decreased upon chilling and increased to the level of control on termination of chilling. $H_2O_2$ was accumulated during chilling up to the level of $5.5\;{\mu}mol/g$ fresh weight while at $25^{\circ}C$ maintained a relatively constant $H_2O_2$ level of $4\;{\mu}mol/g$ FW. All together, it appears that low temperature, in part, by increasing enzyme levels of IAA degradation system and accumulating $H_2O_2$, down-regulates endogenous level of IAA in etiolated pea shoots.