• Applied Biological Chemistry
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• v.36 no.6
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• pp.533-538
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• 1993

The Wx protein, known as starch synthase or starch glucosyl transferase (E.C. 2.4.1.11), is responsible for the amylose synthesis. In an effort to explain the mechanism of amylose biosynthesis, the starch synthase known as Wx protein was identified by analyzing the various wx rice mutants with SDS-PAGE of proteins extracted from rice starch. Finally, the 66 kDa protein was purified by extracting the starch-bound protein fractions followed by Suprose 12 gel filtration chromatography.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.1702-1706
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• 2006

In the field of rice research, insertional mutants have become a valuable resource for studies of gene function. However, a well-designed database yet in the area of rice functional genomics. The relevant data are widely distributed and independently managed by the individual research groups. Heterogeneous data format in the distributed database systems causes many problems related to redundancy and compatibility. In this research, integration of the distributed databases using agent technology is pursued. In particular, a data integration agent, an ontology agent, a comparison agent, and resource agents are designed, whereby the integrated database is maintained. Moreover a framework for the web-based information system, which provides information to biologists and permits biologists to add new data to the database, is proposed. To establish an interoperable data format, an XML-based data model is also developed adopting ontology concept.

• 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.

• 한국균학회소식:학술대회논문집
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• 2014.10a
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• pp.43-43
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• 2014

The rice blast disease caused by of Magnaporthe oryzae is one of the most destructive diseases of rice. By the microarray analysis, we profiled expression changes of genes during conidiation and found out many putative genes that are up-regulated. Among those, we first selected MGG_06399 encoding a dual-specificity tyrosine-regulated protein kinase (DYRK), homologous to YAK1 in yeast. To investigate functional roles of MoYAK1, We made ${\Delta}Moyak1$ mutants by homology dependent gene replacement. The deletion mutant showed a remarkable reduction in conidiation and produced abnormally shaped conidia smaller than those of wild type. The conidia form ${\Delta}Moyak1$ were able to develop a germ tube, but failed to form apppressoria on a hydrophobic coverslip. The ${\Delta}Moyak1$ formed appressria on a hydrophobic cover slip when exogenous cAMP was induced, but the appressoria shape was abnormal. The ${\Delta}Moyak1$ also formed appressoria abberent in shape on onion epidermis and rice sheaths and failed to penetrate the surface of the plants. These data indicate that MoYAK1 is associated with cAMP/PKA pathway and important for conidiation, appressorial formation and pathogenic development in Magnaporthe oryzae. Detailed characterization of MoYAK1 will be presented.

• BMB Reports
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• v.41 no.8
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• pp.581-586
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• 2008

The pre-replication complex (pre-RC), including the core hexameric MCM2-7 complex, ensures that the eukaryotic genome is replicated only once per cell division cycle. In this study, we identified a rice $\underline{m}ini\underline{c}hromosome$ $\underline{m}aintenance$ (MCM) homologue (OsMCM2) that functionally complemented fission yeast MCM2 (CDC19) mutants. We found OsMCM2 transcript expression in roots, leaves, and seeds, although expression levels differed slightly among the organs. Likewise, the OsMCM2 protein was ubiquitously expressed, but it was downregulated when nutritients were limiting, indicating that MCM2 expression (and therefore cell cycle progression) requires adequate nutrition. Yeast two-hybrid and GST pull-down assays demonstrated that OsMCM2 interacted with the COP9 signalosome 5 (CSN5). Taken as a whole, our results indicated that OsMCM2 functions as a subunit of the rice MCM complex and interacts with CSN5 during developmental regulation.

• Proceedings of the Plant Resources Society of Korea Conference
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• v.18 no.1
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• pp.134-135
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• 2005

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.89-89
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• 2003

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.10a
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• pp.127-127
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• 2003

• Korean Journal of Food Science and Technology
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• v.32 no.1
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• pp.75-81
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• 2000

The processing properties for rice bread were examined using eight kinds of endosperm mutant rice. The varietal differences among eight kinds of endosperm mutant rice having the respective sugar contents and amylose contents were studied. The water absorptions of these eight cultivars were observed to have significant differences among the cultivars, revealing the water absorption ability of Shrunken(shr.) was 61.5%, and that of Punchilmi(fl) was 48.4%. In addition, the experiments using Whachungbyeo, Nampungbyeo and their mutant cultivars showed that the maximum water absorption was tend to be negatively correlated with the amylose content of each rice cultivars. This study also showed that the rice breads made by dry-milling was better in shape, mechanical properties(hardness, springiness, adhesiveness, chewiness) and texture tested using sensory evaluation than that made by wet-milling.

• The Plant Pathology Journal
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• v.30 no.4
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• pp.367-374
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• 2014

Genomes contain a large number of unique genes which have not been found in other species. Although the origin of such "orphan" genes remains unclear, they are thought to be involved in species-specific adaptive processes. Here, we analyzed seven orphan genes (MoSPC1 to MoSPC7) prioritized based on in planta expressed sequence tag data in the rice blast fungus, Magnaporthe oryzae. Expression analysis using qRT-PCR confirmed the expression of four genes (MoSPC1, MoSPC2, MoSPC3 and MoSPC7) during plant infection. However, individual deletion mutants of these four genes did not differ from the wild-type strain for all phenotypes examined, including pathogenicity. The length, GC contents, codon adaptation index and expression during mycelial growth of the four genes suggest that these genes formed during the evolutionary history of M. oryzae. Synteny analyses using closely related fungal species corroborated the notion that these genes evolved de novo in the M. oryzae genome. In this report, we discuss our inability to detect phenotypic changes in the four deletion mutants. Based on these results, the four orphan genes may be products of de novo gene birth processes, and their adaptive potential is in the course of being tested for retention or extinction through natural selection.