• Journal of Microbiology
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• v.45 no.1
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• pp.15-20
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• 2007

The majority of soil microorganisms can derive ethylene from L-methionine (L-MET), while some rhizobacteria can hydrolyze 1-aminocyclopropane-1-carboxylate (ACC) due to their ACC-deaminase activity. In this study, three strains having either ACC-deaminase activity (Pseudomonas putida biotype A, $A_7$), or the ability to produce ethylene from L-MET (Acinetobacter calcoaceticus, $M_9$) or both (Pseudomonas fluorescens, $AM_3$) were used for inoculation. The highly ethylene specific bioassay of a classical 'triple' response in pea seedlings was used to investigate the effect of the inoculation with the rhizobacteria in the presence of 10 mM ACC or L-MET. The exogenous application of ACC had a concentration-dependent effect on the etiolated pea seedlings in creating the classical 'triple' response. The inoculation with P. putida diluted the effect of ACC, which was most likely due to its ACC-deaminase activity. Similarly, the application of $Co^{2+}$ reduced the ACC-imposed effect on etiolated pea seedlings. In contrast, the inoculation of A. calcoaceticus or P. fluorescens in the presence of L-MET caused a stronger classical 'triple' response in etiolated pea seedlings; most likely by producing ethylene from L-MET. This is the first study, to our knowledge, reporting on the comparative effect of rhizobacteria capable of utilizing ACC vs L-MET on etiolated pea seedlings.

• 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.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.68-72
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• 1990

Little is known about the regulation of IAA level in plants under low temperature. On exposing 6-day-old etiolated pea(Pisum sativum L. var. Sparkle) seedlings grown at $25^{\circ}$ to $5^{\circ}$ for 3 days, free IAA level decreased from 17.6 to 4.9 ng/g fresh weight(that is, from 68 to 10 pmol/shoot) and total IAA level from 113.2 to 60.8 ng/g FW. The level of free tryptophan, precusor of IAA, also decreased from 583 to 414 nmol/g FW and that of free phenylalanine and tyrosine, products of shikimic acid pathway along with tryptophan, decreased from 3,168 to 2,327 nmol/g FW. Thus low temperature was found to down-regulate the level of endogenous IAA, in part, by reducing tryptophan biosynthesis in etiolated pea shoots.

• Journal of Photoscience
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• v.9 no.2
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• pp.94-97
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• 2002

Light is one of the most important environmental factors that influence plant growth and development. It does not function independently but exerts its role through coordinated interactions with intrinsic developmental programs, such as hormonal regulation. One typical example is hypocotyl growth in which light signals are modulated through growth hormones. However, the underlying molecular mechanisms are largely unknown. We demonstrated that brassinosteroids play an important role in the light signal transduction in etiolated hypocotyl growth. A light-responsive Ras-like G-protein, Pra2 from pea, physically and functionally interacts with a cytochrome P450 that specifically catalyzes C-2 hydroxylation in brassinosteroid biosynthesis. The cytochrome P450 expression, along with Pra2, is induced in the dark and predominantly localized in the rapidly elongating zone of etiolated pea epicotyls. Transgenic plants with a reduced level of Pra2 exhibit a dark-specific dwarfism, which is completely rescued by brassinosteroid application. On the contrary, overexpression of the cytochrome P450 results in enhanced hypocotyl growth even in the light, which phenocopies the etiolated hypocotyl growth. It is therefore envisioned that Pra2 is a molecular switch that mediates the crosstalk between light and brassinosteroids in the etiolation process.

• Korean Journal of Environmental Agriculture
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• v.4 no.1
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• pp.43-51
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• 1985

To identify amino acid conjugates of indole-3-acetic acid(IAA) in plants, 23 amino acid conjugates of IAA were synthesized and characterized by UV and IR spectroscopies, and thinlayer and high performance liquid chromatographies. In etiolated pea(Pisum sativum L. var. Sparkle) shoots, aspartic and glutamic acid conjugates of IAA were tentatively identified as metabolites of endogenous IAA by thin-layer and high performance liquid chromatography, and by alkaline hydrolysis of the conjugates.

• Journal of Photoscience
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• v.4 no.3
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• pp.141-145
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• 1997

Polymerase chain reaction(PCR) was conducted with a pea cDNA library using two primers synthesized from homology analysis of amino acid sequences for animal and plant cytosolic FBPases. A PCR product with 650 bp long was cloned into pGEM-T vector and sequenced. The deduced amino acid sequence of the cDNA fragment was 98, 91, and 85% homologous with those of cytosolic FBPases from spinach, sugarbeet, and sugarcane, respectively. It was 51% homologous with amino acid sequence of FBPase from pea chloroplasts. Northern blot analysis was proceeded with the cDNA clone resulting that 1.2 kb transcript was highly expressed in light-grown pea leaves but almost not expressed in dark-grown etiolated pea seedlings. When peas grown in the light for 10 days were transferred to darkness, the transcript was gradually decreased with dark treatment, indicating that the expression of the enzyme was induced by continuous white light but suppressed by dark treatment. Pea cytosolic FBPase was highly expressed in leaves with trace amounts in stems. but almost not expressed in roots.

• BMB Reports
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• v.32 no.4
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• pp.393-398
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• 1999

Acetolactate synthase (ALS) catalyzes the first reaction common to the biosynthesis of L-valine, L-leucine, and L-isoleucine. ALS is the target site of several classes of herbicides, including the sulfonylureas, the imidazolinones, and the triazolopyrimidines. Two forms of ALS (ALS I and ALS II) which have different affinity for Heparin have been separated from etiolated pea seedlings. The substrate saturation curves of both ALS I and ALS II were hyperbolic in contrast to previous reports. The two forms of ALS showed significant differences in their physical and kinetic properties. The values of $K_m$ for ALS I and ALS II were 9.0 mM and 4.8 mM, respectively. The pI values for ALS I and ALS II were determined to be 5.3 and 5.75 by isoelectric focusing, respectively. The native molecular weights for ALS I and ALS II obtained by nondenaturing gel electrophoresis and activity staining were 124 and 244 kDa, respectively. They also exhibited different sensitivity to feedback inhibition by end-product amino acids and inhibition by Cadre, an imidazolinone herbicide.

• Proceedings of the Korean Society of Potoscience Conference
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• spring
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• pp.33-33
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• 2000

• Journal of Plant Biology
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• v.38 no.4
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• pp.343-348
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• 1995

Treatment of Pisum sativum tissue with the protein kinase inhibitor staurosphorine resulted in impairment of 3H-indoleacetic acid transport in etiolated stem segments. The transport inhibitiion was accompanied by an increase in net uptake of labeled auxin in the tissue. The magnitude of auxin accumulation in tissue treated with the phytotropin N-1-naphthylphthalaic acid (NPA) which specifically blocks the efflux of auxin in the plasma membrane was reduced by the protein kinase inhibitor, suggesting that inhibition of protein phosphorylation could lead to hindrance of the auxin-exporting function of NPA receptors. The flavonoid genistein which is also known to inhibit protein kinase likewise reduced NPA-induced auxin accumulation. However, the flavonoid did not bring about auxin accumulation by itself, nor did it inhibit auxin transport. In view of the finding that the flavonoid also competes with NPA for a common binding site, a mechanism for the flavonoid effect on the NPA action will be proposed.

• Applied Biological Chemistry
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• v.32 no.2
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• pp.162-169
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• 1989

Tryptophan, indole-3-acetaldehyde, indole-3-acetic acid(IAA), and indole-3-aldehyde were identified as endogenous IAA analogues in etiolated pea(Pisum sativum L. var. 'Sparkle') shoots, which suggests a metabolic sequence(s) of tryptophan${\rightarrow}$(?)${\rightarrow}$indole-3-acetaldehyde${\rightarrow}$IAA${\rightarrow}$indole-3-aldehyde occurring in pea plants. IAA-rhamnose and IAA-glucose were tentatively confirmed as IAA conjugates.