• Korean Journal of Environmental Agriculture
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• v.28 no.4
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• pp.447-452
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• 2009

A bacterium, which was named to be Bacillus cereus A-139, secreting auxin was isolated from the east coast sand dunes in Korea. The secretion of auxin was confirmed by HPLC. When cultured in LB broth, Bacillus cereus A-139 produced $16.12\;{\mu}$g/mL auxin after 8 days in LB broth. Bacillus cereus A-139 produced $49\;{\mu}$g/mL auxin and $162.6\;{\mu}$g/mL by the addition of 2% tryptone and 0.1% tryptophan, respectively. The root growth of Arabidopsis thaliana was retarded by Bacillus cereus A-139 culture broth up to 57% but the formation of lateral roots was increased up to almost twice after 4 days incubation. Also the formation of lateral roots of mung bean was increased up to 57% after 10 days incubation.

• Journal of Plant Biology
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• v.32 no.4
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• pp.265-274
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• 1989

The effect of Ca2+ on auxin-induced ehtylene production in etiolated mungbean (Vigna radiata W.) hypocotyls was studied. Auxin-induced ethylene production by mungbean seedlings which had been germinated in the presence of 5-10mM Ca2+ (High Ca2+ ; HC) is greater than that by seedlings which had been germinated in distilled water (Low Ca2+ ; LC). The effect of Ca2+ on auxin-induced ethylene production was greatly increased after 12hr of incubation period. The stimulation of auxin-induced ethylene production by Ca2+ was specific, since divalent cations, such as Mg2+ and Mn2+ did not enhance auxin-induced ethylene production. Calcium also promoted ethylene evoluation induced by methionine and 1-Aminocyclopropane-1-carboxylic acid(ACC). The effect of Ca2+ on auxin-induced ethylene production was not caused by increase in free IAA or ACC contents of hypocotyl tissue. Dimethyl sulfoxide and Triton X-100, that disrupts the emembranes, inhibited ethylene production to a greater extent in LC segments than in HC segments. Addition of Ca2+ to the incubation medium for LC segments resulted in enchancement of ethylene production probalby because the membrane integrity is supported under these conditions. Comparison of activity of Ethylene Forming Enzyme(EFE) in LC and HC hypocotyl segments indicated that the enzyme activity of HC was about 2 times higher than that of L.C. It is suggested that Ca2+ increases the activity of plasma membrane-bound EFE through its stabilizing effect onn the membrane, which in turn brings about promotion of ethylene production.

• Journal of Plant Biology
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• v.34 no.4
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• pp.325-330
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• 1991

The ability of several auxin analogs to induce ethylene production was tested in the corn coleoptile. The synthetic auxins 1-naphthaleneacetic acid (1-NAA) and 2, 4-dichlorophenoxyacetic acid (2, 4-D) had strong stimulatory effects on ethylene induction surpassing that of IAA. Both 2-naphthalaneacetic acid (2-NAA) and 2, 6-dichlorophenoxy acetic acid (2, 6-D), structural analogs of these auxins, respectively, were found to be inactive. Treatment with NPA, a strong inhibitor of polar auxin transport, led to drastic increase in IAA-induced ethylene production while it has bo effect on ethylene production induced by 1-NAA. A positive correlative existed between intracellular auxin level and ethylene production.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.180-188
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• 2019

Auxin plays a crucial regulatory role in plant growth and development processes. Three major classes of auxin-responsive transcription factors controlled by the Auxin/indole-3-acetic acid (Aux/IAA), Gretchen Hagen 3 (GH3), and small auxin up RNA (SAUR) genes regulate auxin signaling. Aux/IAA, in particular, encodes short-lived nuclear proteins that accumulate rapidly in response to auxin signaling. In this study, we isolated a PagAux/IAA1 gene from poplar (Populus alba ${\times}$ P. glandulosa) and investigated its expression characteristics. The PagAux/IAA1 cDNA codes for putative 200 amino acids polypeptide containing four conserved domains and two nuclear localization signals (NLSs). Utilizing Southern blot analysis, we confirmed that a single copy of the PagAux/IAA1 gene was present in the poplar genome. The expression of this gene is specific to leaves and flowers of the poplar. PagAux/IAA1 expressed in the early exponential growth phase of cell-cultured in suspension. PagAux/IAA1 expression level reduced in drought and salt stress conditions, and the presence of plant hormones such as abscisic acid. However, expression enhanced in cold stress, cambial cell division, and presence of plant hormones such as gibberellic acid and jasmonic acid. Thus, these results suggest that PagAux/IAA1 participates in cold stress response as well as developmental processes in the poplar.

• Microbiology and Biotechnology Letters
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• v.34 no.2
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• pp.94-100
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• 2006

To isolate a bacterium that produces plant growth promoting hormone, a total of 29 bacteria were obtained from the soil in Gyeongsan, Korea. Among these, 14 strains were selected by their positive reaction on Salkowski to produce auxin. All of these were then tested for their property to produce siderophore using CAS (chrome azurol S) blue agar, and one was chosen for its ability to produce both, auxin and siderophore. This strain, denoted, AHl8, showed 1.5 times higher adventitious root induction rates than controls, using mung-beans. The strain also showed efficient biocontrol properties towards Fusarium-wilt of tomatoes in artificial pot assays. The strain was identified as Bacillus subtilis by 16s rDNA comparison and Biolog analyses. Growth and media conditions for Bacillus subtilis AH1 8 to highly produce siderophore were also investigated.

• Korean Journal of Plant Tissue Culture
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• v.26 no.1
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• pp.27-30
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• 1999

The most effective cytokinin for shoot multiplication in vitro of Prunus persica cv. Baekmijosaeng, Okubo, and Yumyeong was 2.0 mg/L BA. As the result of combinational treatment of BA and auxin sources (IAA, IBA and NAA), 2.0 mg/L BA with 1.0 mg/L IAA was the most effective for shoot multiplication of cv. Baekmijosaeng. The most effective auxin source for rooting was IAA and the concentration was 5.0 mg/L and 3.0 mg/L for cv. Baekmijosaeng and Okubo, respectively.

• BMB Reports
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• v.28 no.6
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• pp.552-555
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• 1995

Treatment of microsomal vesicles isolated from etiolated Pisum sativum L cv. Alaska epicotyl tissue with agents inhibiting protein dephosphorylation, namely NaF and/or ATP, resulted in increased binding of the phytotropin NPA to the putative auxin efflux carriers localized on the plasma membrane. The phytotropin effect was especially conspicuous if the vesicles were simultaneously treated with Triton X-100. Kinetic analysis of the binding indicated the existance of two distinct sites for NPA, each having different affinities. Increased binding of the phytotropin to the membrane where protein dephosphorylation was inhibited was attributable to the increased ligand affinity of both sites. Treatment of tissue segments with flubride was found to enhance in vivo auxin transport. Implications of covalent modification of the auxin efflux carrier complex for the regulation of membrane transport of auxin molecules are discussed.

• Journal of Plant Biology
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• v.19 no.2
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• pp.41-44
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• 1976

Ethylene was found to reverse the direction of gravity-induced lateral auxin transport and to cause an accumulation of auxin in the physically upper sides of horizontally placed pea shoots. The pea shoot displayed a slightly positive (downward) geotropic curvature in the presence of applied ethylene. Golgi bodies were found to be distributed preferentially in the bottom halves of cells as against the top halves following geotropic stimulation, and this pattern of intracellular distribution of dictyosomes was also reversed by ethylene treatment. Intracellular displacement of amyloplsts as a result fo geotropic induction was not reversed by the action of ethylene. In view of a positive correlation between the direction of auxin movement and the displacement patern of dictyosomes, it is suggested that the Golgi bodies are involved in the perception of gravity and/or subsequent redistribution of auxin or differential elongation in geotropism.

• Plant Biotechnology Reports
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• v.3 no.4
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• pp.293-299
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• 2009

Auxin-binding protein 57 ($ABP_{57}$), a soluble auxin-binding protein, acts as a receptor to activate plasma membrane (PM) $H^+-ATPase$. Here, we report the cloning of abp57 and the biochemical characterization of its protein expressed in E. coli. The analysis of internal amino acid sequences of $ABP_{57}$ purified from rice shoots enabled us to search for the corresponding gene in protein DB of NCBI. Further BLAST analysis showed that rice has four abp57-like genes and maize has at least one homolog. Interestingly, Arabidopsis seems to have no homolog. Recombinant $ABP_{57}$ expressed in E. coli caused the activation of PM $H^+-ATPase$ regardless of the existence of IAA. Scatchard analysis showed that the recombinant protein has relatively low affinity to IAA as compared to natural $ABP_{57}$. These results collectively support the notion that the cloned gene is responsible for $ABP_{57}$.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.171-177
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• 2022

The precise homeostatic regulation of local auxin accumulation in xylem precursors of cambium stem cell tissues is one of the most important mechanisms for plant vascular patterning and radial secondary growth. Walls are thin (WAT1), a novel intracellular auxin transporter, contributes directly to the auxin accumulation maxima in xylem precursors. According to recent research, the auxin signaling activated pathway-related gene network was significantly enriched during the secondary growth of Panax ginseng storage roots. These imply that during P. ginseng root secondary growth, specific signaling mechanisms for local auxin maxima in the vascular cambial cells are probably triggered. This study identified four WAT1-like genes, PgWAT1-1/-2 and PgWAT2-1/-2, in the P. ginseng genome. Their expression levels were greatly increased in nitratetreated storage roots stimulated for secondary root growth. PgWAT1-1 and PgWAT2-1 were similar to WAT1 from Arabidopsis and tomato plants in terms of their subcellular localization at a tonoplast and predicted transmembrane topology. We discovered that overexpression of PgWAT1-1 and PgWAT2-1 was sufficient to compensate for the secondary growth defects observed in slwat1-copi loss of function tomato mutants. This critical information from the PgWAT1-1 and PgWAT2-1 genes can potentially be used in future P. ginseng genetic engineering and breeding for increased crop yield.