• Journal of Plant Biotechnology
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• v.40 no.3
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• pp.125-134
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• 2013

Lipid droplets called plastoglobules are present in all plastid types. In chloroplasts, they are surrounded by the outer lipid monolayer from and connected to thylakoid membrane. The plastoglobule core contains the neutral lipids, which includes prenylquinones, triacylglycerols, and carotenoids. During stress and various developmental stages such as senescence, the size and number of plastoglobules increase due to the accumulation of lipids. Plastoglobules proteome revealed the presence of metabolic enzymes as well as structural proteins, plastoglobulins/fibrillins. Among the metabolic enzymes, the tocopherol cyclase, VTE1 and the NADPH quinine dehydrogenase, NDC1 have demonstrated that these participate in isoprenoid lipid metabolic pathways at the plastoglobule, notably in the metabolism of prenylquinones (tocopherol, plastoquinol and phylloquinone).

• Journal of Life Science
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• v.23 no.1
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• pp.1-7
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• 2013

Understanding salt tolerance mechanisms is important for the increase of crop yields, and so, several screening approaches were developed to identify plant genes which are involved in salt tolerance of plants. Here, we transformed the Arabidopsis cDNA library into a salt-sensitive calcineurin (CaN)-deficient ($cnb{\Delta}$) yeast mutant and isolated the colonies which can suppress salt-sensitive phenotype of $cnb{\Delta}$ mutant. Through this functional complementation screen, a total of 34 colonies functionally suppressed the salt-sensitive phenotype of $cnb{\Delta}$ yeast cells, and sequencing analysis revealed that these are 9 genes, including CaS, AtSUMO1 and AtHB-12. Among these genes, the ectopic expression of CaS gene increased salt tolerance in yeast, and CaS transcript was up-regulated under high salinity conditions. CaS-antisense transgenic plants showed reduced root elongation under 100 mM NaCl treatment compared to the wild type plant, which survived under 150 mM NaCl treatment, whereas CaS-antisense transgenic plant leaves turned yellow under 150 mM NaCl treatment. These results indicate that the expression of CaS gene is important for stress tolerance in yeast and plants.

• Journal of Life Science
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• v.17 no.1 s.81
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• pp.1-5
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• 2007

The Precesses for leaf development in dicotyledonous plants are surprisingly complex, while the mechanism of controlling and coordinating them is poorly understood. To characterize the fundamental features of the leaf development of Arabidopsis, we first attempted to isolate mutants that alter leaf morphology. Here, leaf morphological mutant of Arabidopsis, lanceolatal (lan1) which has small and narrow leaves have isolated and characterized. To clarify the function of LAN1 in organ development, we characterized lan1-7 mutant using an anatomical and genetic approach. The lan1-7 mutant had reduced size of foliage leaves and reduced dimensions of stems. A reduction both in cell size and in cell number was evident at the cellular level in the lan1 mutant, revealing that LAN1 gene appears to affect cell division at an earlier stage and cell elongation throughout the development of leaf primordia. from the analysis of heterogeneous plant with lan1 mutation and 35S-AG transgenic plant, AG gene is revealed to regulate leaf morphology under the control of 35S promoter. Thus, MADS-box gene was revealed to have some relationship to that of LAN1 gene at certain stage in leaf development processes.

• Journal of Life Science
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• v.28 no.10
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• pp.1132-1139
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• 2018

The stability of diverse cellular proteins in eukaryotes is regulated via ubiquitination. Moreover, E3 ligase plays a crucial role in determining substrate specificity and transfers ubiquitins into the substrates during the ubiquitination process. As a type of multi-subunit E3 ligase, cullin4 (CUL4)-based E3 ligase (CRL4) complex is involved in a variety of cellular processes, such as hormonal and stress responses in plants. In spite of several reports on the versatile roles of CRL4 in various signalings in Arabidopsis, CRL4's function in rice has been poorly known. To learn about CRL4-mediated cellular processes in rice in more detail, OsCUL4 that exhibits the highest homology with Arabidopsis CUL4 was isolated, and its expression patterns in various tissues and in response to plant hormones and abiotic stresses were monitored. Exogenous application of ABA or cytokinin increased the transcript levels of the OsCUL4 gene. Moreover, OsCUL4 was significantly upregulated in response to drought and salt stresses. These findings imply that OsCUL4 may be functionally related to ABA- and/or cytokinin-mediated cellular responses. OsCUL4 directly interacted with OsDDB1, an adaptor protein of CRL4, indicating that OsCUL4 can act as a scaffold protein of CRL4. An expression study on the OsCUL4 gene from this report could be used as a starting point to elucidate cellular responses in which a CRL4-mediated ubiquitination process is involved in rice.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.127-132
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• 1999

Protoplasts were isolated from the leaf mesophyll tissue of in vitro 4-weeks-old Arabidopsis thaliana and cultured in MS liquid medium supplemented with 2.0 mg/L NAA, 0.5 mg/L BAP and 9% mannitol in the dark at $25^{\circ}C$. When protoplast-derived microcolonies were dehydrated, the frequency of callus induction enhanced approximately 7-fold higher compared with non-dehydrated microcolonies in CP medium. Fifty callus lines were selected from dehydrated microcolonies. Shoots were efficiently initiated from the green spots of the selected shoot forming calli cultured on MS regeneration medium supplemented with 0.05 mg/L IAA, 7.0 mg/L 2-iP and 30 g/L sucrose under continous illumination for 4 weeks. Shoot regeneration frequencies (calli regenerating at least one shoot) were 3.5%~56%. Histological observations of shoot forming callus revealed that tracheary elements initiated from inner compact cells, and that meristemoids developed to shoot primordia and shoots. Roots were induced from these regenerating shoots on MS medium without phytohormones. These regenerants were successfully transplanted into potting soil. Morphological characterization of 50 protoplast-derived plants showed that the frequency of normal type was 78%.

• Korean Journal of Plant Tissue Culture
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• v.25 no.3
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• pp.195-200
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• 1998

Callus induction from leaf and stem explants of Arabidopsis thaliana was successfully obtained when leaf explants were cultured on MS medium containing 2.0 mg/L 2,4-D in the dark and also, when stem explants were cultured on CP medium containing 0.5 mg/L 2,4-D and 0.1 mg/L BAP. Explant-derived sliced calli were suspension-subcultured every week in CP liquid medium with 0.5 mg/L 2,4-D and 0.1 mg/L BAP in the dark, and shoot-forming cell clusters of nodular, pale yellow and knobby type were selected after 7-8 weeks of culture. Shoots were initiated from the green spots of the selected shoot forming calli cultured on MS regeneration medium containing 0.05 mg/L IAA, 7.0 mg/L 2-iP and 30 g/L sucrose under continous illumination for four weeks. Shoot regeneration frequency (calli regenerating at least one shoot) was more than 50%. For plant regeneration, excised shoots were trnasferred to hormone free medium for root initiation after 4 weeks of culture. The regenerants were bolting after 2 weeks of culture and formed in vitro flowering buds within bracts after 4 weeks of culture.

• Journal of Life Science
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• v.33 no.1
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• pp.34-42
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• 2023

In a signal transduction network, from the perception of stress signals to stress-responsive gene ex- pression, binding of various transcription factors to cis-acting elements in stress-responsive promoters coordinate the adaptation of plants to abiotic stresses. Among the AP2/ERF transcription factor family genes, group VII ERF genes, such as RAP2.12, RAP2.2, RAP2.3, AtERF73/HRE1, and AtERF71/ HRE2, are known to be involved in the response to hypoxia stress in Arabidopsis. In this study, we dissected the HRE1 promoter to identify hypoxia-responsive region(s). The 1,000 bp upstream promoter region of HRE1 showed increased promoter activity in Arabidopsis protoplasts and transgenic plants under hypoxia conditions. Analysis of the promoter deletion series of HRE1, including 1,000 bp, 800 bp, 600 bp, 400 bp, 200 bp, 100 bp, and 50 bp upstream promoter regions, using firefly luciferase and GUS as reporter genes indicated that the -200 to -100 region of the HRE1 promoter is responsible for the transcriptional activation of HRE1 in response to hypoxia. In addition, we identified two putative hypoxia-responsive cis-acting elements, the ERF-binding site and DOF-binding site, in the -200 to -100 region of the HRE1 promoter, suggesting that the expression of HRE1 might be regulated via the ERF transcription factor(s) and/or DOF transcription factor(s). Collectively, our results suggest that HRE1 contains hypoxia-responsive cis-acting elements in the -200 to -100 region of its promoter.

• Journal of Environmental Science International
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• v.15 no.2
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• pp.157-162
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• 2006

This experiment was carried out to investigate the effects of mercury and arsenic on the growth of Arabidopsis thaliana when treated with three different concentrations. When treated with mercury, there was no noticeable difference in the growth of the plant between the group treated with $0.5\;{\mu}g/L$ (the effluent standard established by the Ministry of Environment) and the group treated with the concentration 100 times higher. They both showed almost the same level of growth as that of the normal plant. But the group of the concentration 10 times higher showed significantly $10\%$ more growth compared with the normal plant. When treated with arsenic, the three different groups all showed a little more growth compared with the normal plant. Interestingly, the group of the concentration 10 times higher than the official standard concentration of arsenic $(50\;{\mu}g/L)$ showed the highest level of growth, significantly $20\%$ more than the normal plant. These results show that some amount of mercury and arsenic in the soil do not have much effect on the growth of Arabidopsis thaliana, and that optimum concentrations of mercury and arsenic can even stimulate the growth of the plant.

• Journal of Environmental Science International
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• v.12 no.6
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• pp.659-664
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• 2003

The experiment was carried out to investigate the effects of sulfuric acid and nitric acid among the main components of simulated acid rain (SAR) on the growth of vegetative organs and seed germination of Arabidopsis thaliana. The Arabidopsis treated with SAR supplemented with sulfuric and nitric acids, respectively, showed 28% and 30% decrease of shoot and root growth compared to the control plants, and also many necrotic spots on leaf surfaces after SAR treatment were observed. The shoot and root length for plants grown with nitric acid rain was 14% and 17% lower, respectively, compared to the control, whereas those grown with sulfuric acid rain was 24% and 25% lower than control plants. When Arabidopsis seeds were sown in distilled water, germination rate was 100% after 7 days. However, 80% in SAR medium supplemented with sulfuric and nitric acids, 88% in sulfuric acid rain medium and 93% in nitric acid rain medium. The germination abilities of seeds harvested from SAR supplemented with sulfuric and nitric acids, sulfuric acid rain, and nitric acid rain were 73%, 73% and 94%, respectively. Consequently, sulfuric acids showed more inhibitory effects than nitric acids on the growth of vegetative organs as well as germination rates in Arabidopsis.

• Journal of Environmental Science International
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• v.12 no.12
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• pp.1303-1308
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• 2003

This experiment was carried out to investigate the effects of heavy metals (cadmium, chromium, copper and lead) on the seed germination of Arabidopsis thaliana, and examinated the removal effects of biostone and green tea on the heavy metal toxicity. Cadmium and chromium among the four heavy metals had no effect on the seed germination even in the concentration fifty times higher than in the official standard concentration of pollutant exhaust notified by the Ministry of Environment. However, seeds were not germinated in the concentration of copper ten times higher and in the concentration of lead fifty times higher than the official standard concentration. When seeds were sown in the solutions of lead (15, 20, 25 and 30 mg/L) and copper(15 and 20 mg/L), the seed germination rates were 0％ and less than 10％, respectively. However, when biostone(3 g/30 $m\ell$) was added, the seed germination rate was 100％ in all the concentrations. The germination rate was 100％ in distilled water and copper solution (5 mg/L). However, green tea (0.2 g/30 $m\ell$) was added, the seed germination rate was 0％ in both. The results show that cadmiun and chromium had no effect on the seed germination, but lead and copper decreased the rate of seed germination of Arabidopsis thaliana, Biostone removed heavy metal toxicity, but green tea did not removed heavy metal toxicity during germination.