• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.206.4-206
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• 2003

No Abstract, See Full Text

• Interdisciplinary Bio Central
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• v.3 no.1
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• pp.2.1-2.4
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• 2011

Arabidopsis is well-known to the world's plant research community as a model plant. Many significant resources and innovative research tools, as well as large bodies of genomic information, have been created and shared by the research community, partly explaining why so many researchers use this small plant for their research. The genome sequence of Arabidopsis was fully characterized by the end of the $20^{th}$ century. Soon afterwards, the Arabidopsis research community began a 10-year international project on the functional genomics of the species. In 2001, at the beginning of the project, the RIKEN BioResource Center (BRC) started its Arabidopsis resource project. The following year, the National BioResource Project was launched, funded by the Japanese government, and the RIKEN BRC was chosen as a core facility for Arabidopsis resource. Seeds of RIKEN Arabidopsis transposon-tagged mutant lines, activation-tagged lines, full-length cDNA over-expresser lines, and natural accessions, as well as RIKEN Arabidopsis full-length cDNA clones and T87 cells, are preserved at RIKEN BRC and distributed around the world. The major resources provided to the research community have been full-length cDNA clones and insertion mutants that are suitable for use in reverse-genetics studies. This paper provides an overview of the Arabidopsis resources made available by RIKEN BRC and examples of research that has been done by users and developers of these resources.

• Journal of Plant Biotechnology
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• v.38 no.1
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• pp.94-104
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• 2011

Salt stress is a major environmental factor influencing plant growth and development. To identify salt tolerance determinants, we systematically screened salt sensitive rice mutants by use of the Activator/Dissociation (Ac/Ds) transposon tagging system. In this study, we focused on the salt sensitive mutant line, designated SSM-1. A gene encoding a NAC transcription factor homologue was disrupted by the insertion of a Ds transposon into SSM-1 line. The OsNAC075 gene (EU541472) has 7 exons and encodes a protein (486-aa) containing the NAC domain in its N-terminal region. Sequence comparison showed that the OsNAC075 protein had a strikingly conserved region at the N-terminus, which is considered as the characteristic of the NAC protein family. OsNAC075 protein was orthologous to Arabidopsis thaliana ANAC075. Phylogenetic analysis confirmed OsNAC075 belonged to the OsNAC3 subfamily, which plays an important role in response to stress stimuli. RT-PCR analysis showed that the expression of OsNAC075 gene was rapidly and strongly induced by stresses such as NaCl, ABA and low temperature ($4^{\circ}C$). Our data suggest that OsNAC075 holds promising utility in improving salt tolerance in rice.

• YAKHAK HOEJI
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• v.49 no.3
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• pp.198-204
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• 2005

Human foamy virus (HFV) integrase mediates integration of viral c-DNA into cellular DNA. In this process, HFV integrase recognizes its own viral DNA specifically and catalyzes insertion of viral c-DNA. In order to study catalytic domains and residues, three deletion mutants and two point mutants of HFV integrase were constructed and analyzed with respect to enzymatic activities. The C-terminal deletion mutant showed decreased enzymatic activities while the N-terminal deletion mutant lost the activities completely, indicating that the N-terminal domain is more important than the C-terminal domain in enzymatic reaction. The point mutants, in which an aspartic acid at the 164th position or a glutamic acid at the 200th position of the HFV integrase protein was changed to an alanine, lost the enzymatic activities completely. However, they were well complemented with other defective deletion mutants to recover enzymatic activities partially. Therefore, these results suggest that the aspartic acid and glutamic acid at the respective 164th and 200th positions are catalytic residues for enzymatic reaction.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.62-74
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• 2023

Plant pathogenic Pectobacterium species cause severe soft rot/blackleg diseases in many economically important crops worldwide. Pectobacterium utilizes plant cell wall degrading enzymes (PCWDEs) as the main virulence determinants for its pathogenicity. In this study, we screened a random mutant, M29 is a transposon insertion mutation in the metC gene encoding cystathionine β-lyase that catalyzes cystathionine to homocysteine at the penultimate step in methionine biosynthesis. M29 became a methionine auxotroph and resulted in growth defects in methionine-limited conditions. Impaired growth was restored with exogenous methionine or homocysteine rather than cystathionine. The mutant exhibited reduced soft rot symptoms in Chinese cabbages and potato tubers, maintaining activities of PCWDEs and swimming motility. The mutant was unable to proliferate in both Chinese cabbages and potato tubers. The reduced virulence was partially restored by a complemented strain or 100 µM of methionine, whereas it was fully restored by the extremely high concentration (1 mM). Our transcriptomic analysis showed that genes involved in methionine biosynthesis or transporter were downregulated in the mutant. Our results demonstrate that MetC is important for methionine biosynthesis and transporter and influences its virulence through Pcc21 multiplication in plant hosts.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.4
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• pp.413-419
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• 2011

This study was conducted to determine the physicochemical properties of a giant embryo rice 'P47JB-4-B-5-B' derived from the cross between 'P47', a mutant of 'Hwayoung' induced by T-DNA insertion, and 'Junam'. The grain appearance and chemical components of the embryo were analyzed and compared with a donor cultivar, 'Hwayoung'. The proportion of embryo weight to grain weight of 'P47 JB-4-B-5-B' was 2.2 times heavier (6.7%) than that (3.1%) of 'Hwayoung'. Total free amino acid content (75.81 mg/100 g) of 'P47JB-4-B-5-B' was 2.1 times higher than that of 'Hwayoung'. The GABA content in brown rice was 14.06 mg/100 g in 'P47JB-4-B-5-B' and 6.8 mg/100 g in 'Hwayoung'. Especially, the GABA content in brown rice of 'P47JB-4-B-5-B' remarkably increased (about 33 times from 1.48 mg to 44.81 mg/100 g) 2 days after germination. Continuous frequency distributions and transgressive segregation in embryo length and width were observed in the $F_2$ population of the cross between 'P47' and 'Cheongcheong', indicating that the giant embryo was controlled by quantitative trait loci. However, embryo length and width demonstrated high broad sense heritability, implying that giant embryonic traits could be selected in earlier generations in comparison with other quantitative traits.

• Korean Journal of Plant Resources
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• v.23 no.3
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• pp.248-255
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• 2010

We previously demonstrated that root colonization of the rhizobacterium, Pseudomonas chlororaphis O6, induced expression of a galactinol synthase gene (CsGolS1), and resulting galactinol conferred induced systemic resistance (ISR) against fungal and bacterial pathogens in cucumber leaves. To examine the role of galactinol on ISR, drought or high salt stress, we obtained T-DNA insertion Arabidopsis mutants at the AtGolS1 gene, an ortholog of the CsGolS1 gene. The T-DNA insertion mutant compromised resistance induced by the O6 colonization against Erwinia carotovora. Pharmaceutical application of 0.5 - 5 mM galactinol on roots was sufficient to elicit ISR in wild-type Arabidopsis against infection with E. carotovora. The involvement of jasmonic acid (JA) signaling on the ISR was validated to detect increased expression of the indicator gene PDF1.2. The T-DNA insertion mutant also compromised tolerance by increasing galactinol content in the O6-colonized plant against drought or high salt stresses. Taken together, our results indicate that primed expression of the galactinol synthase gene AtGolS1in the O6-colonized plants can play a critical role in the ISR against infection with E. carotovora, and in the tolerance to drought or high salt stresses.

• Journal of Life Science
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• v.5 no.4
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• pp.162-169
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• 1995

The glpD genes encoding gly-3-p dehydrogenase is essential for the aerobic growth of E. coli on glycerol or gly-3-p. The glpE gene, the function of which is unknownm is transcribed divergently with respect to glpD gene. Expression of the adjacent but divergently transcribed glpD the glpE genes is positively regulated by the cAMP-CRP complex. In this study, for a precise investigation of the functional elements in the regulatory region for transcription activation by cAMP-CRP, deletion mutation have been introducted into the regulatory region. The effect of the deletion mutant on transcriptional regulation was tested in vivo by $\beta$-galctosidase activity. Deletion mutants in the regulatory region of glpD demonstrated that the presence of the CRP-binding site resulted in an sixfold increase in promoter activity. And also deletion mutants of glpE gene demonstrated that the presence of the CRP-binding site resulted in an eightfold increase in promoter activity. Insertion of 22 bp oligomer in the deletion mutants has shown that the CRP binding site is need for maximal expression of glpD and glpE genes. glpD and glpE gene, cAMP-CRP complex, deletion mutant, transcriptional regulation.

• Journal of Microbiology and Biotechnology
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• v.12 no.2
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• pp.242-248
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• 2002

Previously, it was reported that the nonhomologous C-terminal regions of the D-hydantoinases are nonessential for catalysis, but affect the oligomeric structure of the enzyme [3]. In an effort to further confirm the above observation, the C-terminal region-inserted enzyme was constructed by attaching a peptide (22 residues) at the C-terminal of the D-hydantoinase from Bacillus thermocatenulatus GH2, and its structural and biochemical properties were compared with both the wild-type and C-terminal region-truncated enzymes. As a result, native tetrameric D-hydantoinase was dimerized as the truncated enzyme, and the inserted mutant with a new sequence was expressed as a catalytically active form in E. coli. Expression level of the inserted and truncated enzymes were found to be significantly increased compared to the level of the wild-type enzyme, and this appears to be due to the reduced toxic effect of the mutant enzymes on host cells. Dimerized enzymes exhibited increased thermo- and pH stabilities considerably when compared with the corresponding wild-type enzyme. Comparison of the substrate specificity between the mutant and wild-type enzymes suggests that the substrate specificity of the D-hydantoinase is closely linked with the oligomeric structure.

• The Plant Pathology Journal
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• v.39 no.5
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• pp.417-429
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• 2023

Ralstonia solanacearum species complex (RSSC) is a soil borne plant pathogen causing bacterial wilt on various important crops, including Solanaceae plants. The bacterial pathogens within the RSSC produce exopolysaccharide (EPS), a highly complicated nitrogencontaining heteropolymeric polysaccharide, as a major virulence factor. However, the biosynthetic pathway of the EPS in the RSSC has not been fully characterized. To identify genes in EPS production beyond the EPS biosynthetic gene operon, we selected the EPS-defective mutants of R. pseudosolanacearum strain SL341 from Tn5-inserted mutant pool. Among several EPSdefective mutants, we identified a mutant, SL341P4, with a Tn5-insertion in a gene encoding a putative NDP-sugar epimerase, a putative membrane protein with sugar-modifying moiety, in a reverse orientation to EPS biosynthesis gene cluster. This protein showed similar to other NDP-sugar epimerases involved in EPS biosynthesis in many phytopathogens. Mutation of the NDP-sugar epimerase gene reduced EPS production and biofilm formation in R. pseudosolanacearum. Additionally, the SL341P4 mutant exhibited reduced disease severity and incidence of bacterial wilt in tomato plants compared to the wild-type SL341 without alteration of bacterial multiplication. These results indicate that the NDP-sugar epimerase gene is required for EPS production and bacterial virulence in R. pseudosolanacearum.