• Proceedings of the Korean Society of Crop Science Conference
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• 2022.04a
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• pp.110-110
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• 2022

Rice is the world's most important food crop and a major source of nutrition for about two thirds of populations. Northern Vietnam is one of the most important centers of genetic diversity for cultivated rice. In this study, we determined the genetic diversity and population structure of 79 rice landraces collected from northern Vietnam and 19 rice accessions collected from different countries. In total, 98 rice accessions could be differentiated into japonica and indica with moderate genetic diversity and a polymorphism information content of 0.382. We also detected subspecies-specific markers to classify rice (Oryza sativa L.) into indica and japonica. Additionally, we detected five marker-trait associations and rare alleles that can be applied in future breeding programs. Most interestingly, analysis of molecular variance (AMOVA) found genetic differentiation was related to geographical regions with an overall PhiPT (analog of fixation index FST) value of 0.130. More emphasis was given to provide signatures and infer explanations about the role of geographical isolation and environmental heterogeneity in genetic differentiation among regions in landraces from northern Vietnam. Our results suggest that rice landraces in northern Vietnam have a dynamic genetic system that can create different levels of genetic differentiation among regions, but also maintain a balanced genetic diversity between regions.

• Natural Product Sciences
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• v.13 no.4
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• pp.373-377
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• 2007

Antiscratching behavioral effects of the water extract of two black colored rice (BCR) varieties [Oryza sativa L. cv. Heugjinjubyeo (HJ) and Josaengheugchalbyeo (JH)], major pigment of which is cyanindin 3-glucoside, were investigated. Orally administered BCRs' extracts exhibited potent inhibitory activity against scratching behaviors which were induced by compound 48/80 and histamine. The inhibitory effect of Josaengheugchalbyeo in vivo and in vitro were more potent than those of Heugjinjubyeo. These finding suggest that black colored rice, especially Josaengheugchalbyeo, may inhibit scratching behaviors and anaphylaxis reaction by stabilizing membrane.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.66-70
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• 1999

Effects of the enhanced level of L-ascorbic acid (AA) on the water deficit-induced oxidative damage were studied in rice (Oryza sativa L.) seedlings. The seedlings sprayed with 20 to 80 mM L-galactono-${\gamma}$-lactone (GL), a putative precursor of AA, showed 2 to 5-fold higher levels of AA compared with controls. Pretreatment of the seedlings with GL prior to water stress imposition caused virtually no effect on dehydration of tissues during water deficit but substantially mitigated oxidative injury, as accessed by 2-thiobarbituric acid-reactive substances, ${\alpha}$-tocopherol, chlorophylls and ${\beta}$-carotene. Proline accumulation during water stress was also significantly lowered in the treated seedlings. In a complementary experiment, AA retarded photodegradation of ${\alpha}$-tocopherol in isolated thylakoids far more efficiently than glutathione. GL in itself did not show any noticeable reactivity toward ${\alpha}$-tocopheroxyl radical. The results demonstrate the antioxidative function of AA in rice seedlings encountering water-limited environments, suggesting a critical role of AA as a defense against oxidative stress in plants.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.2
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• pp.126-130
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• 2004

This study is to identify the physiological traits of submergence-tolerant varieties of rice plants (Oryza sativa L.) in Yeongnam area, southeastern part of Korea, where the reduction of rice yield due to submergence is remarkably severe. In the present study, two tolerant varieties of rice plants were selected from over 30 rice varieties grown in under a 10-day period. The tolerant varieties selected from a submerged paddy field. As a control, one intolerant variety of rice plant was chosen. Of the tolerant variety Samgangbyeo, rather than Haepyungbyeo, had a lower dissolved oxygen consumption and maintained a higher dry weight than the intolerant variety. The leaf photosynthetic rates (LPS) of the two tolerant varieties were significantly higher than that of the intolerant-variety after four days of submergence treatment. These results indicate that lower dissolved oxygen consumption in a limited pool is prevented by ethylene formation in the tolerant varieties, which may be a mechanism of submergence tolerance.

• The Plant Pathology Journal
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• v.21 no.2
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• pp.149-157
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• 2005

A novel rice (Oryza sativa L.) gene, homologous to Arabidopsis pathogenesis-related NDR1 gene, was cloned from cDNA library prepared from 30 min Magnaporthe grisea -treated rice seedling leaves, and named as OsNDR1. OsNDR1 encoded a 220-aminoacid polypeptide and was highly similar to the Arabidopsis AtNDR1 protein. OsNDR1 is a plasma membrane (PM)-localized protein, and presumes through sequence analysis and protein localization experiment. Overexpression of OsNDR1 promotes the expression of PBZ1 that is essential for the activation of defense/stressrelated gene. The OsNDR1 promoter did not respond significantly to treatments with either SA, PBZ, or ETP. Exogenously applied BTH induces the same set of SAR genes as biological induction, providing further evidence for BTH as a signal. Presumably, BTH is bound by a receptor and the binding triggers a signal transduction cascade that has an ultimate effect on transcription factors that regulate SAR gene expression. Thus OsNDR1 may act as a transducer of pathogen signals and/or interact with the pathogen and is indeed another important step in clarifying the component participating in the defense response pathways in rice.

• Korean Journal of Environmental Agriculture
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• v.21 no.2
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• pp.156-161
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• 2002

Two different cDNA clones for superoxide dismutase (SOD) were isolated from an weedy rice variety (Oryza sativa, cv. Bhutan14Ad) and were introduced into a cultivated rice variety (Oryza sativa, cv. Nakdong) in order to develop the environmental stress-resistant rice plants. Sequence analysis of the cloned cDNAS indicated that the deduced amino acid sequence of SOD-A is 88.4% identical to that of SOD-B. Furthermore, the nucleotide sequence of SOD-A is 99.3% identical to that of a Cu/Zn SOD gene of Oryza sativa (GenBank accession No. L36320). The nueleotide sequence of SOD-B was identical to that of the previously published SOD gene (Accession No. D01000). A cultivated rice variety, Nakdong-byeo, was transformed with chimeric SOD genes containing a actin promoter of rice and pin2 terminator using a particle bombardment technique. Transformed calli were selected on an selection medium containing phosphinothricin (PPT). Transgenic rice plants were regenerated from the PPT-resistant calli. PCR analysis with genomic DNAs from transgenic plants revealed that transgenes are introduced into rice genome.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.4
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• pp.203-214
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• 2017

Environmental toxicity due to cadmium (Cd) pollution in croplands causes critical problems worldwide. Rice (Oryza sativa L.) is an important crop in Asia, including South Korea, and numerous studies have evaluated the relationship between Cd and antioxidants to alleviate Cd uptake from the soil into plants. However, information about the relationship between phosphorus (P) and antioxidants in rice seedlings is still limited with regard to Cd phytotoxicity. We therefore investigated the physiological responses of rice (Oryza sativa L. cv 'Dongjin') seedlings to Cd toxicity and the effect of P application on reactive oxygen species (ROS) and antioxidant changes. The exposure of rice seedlings to $30{\mu}M$ Cd inhibited plant growth; increased the contents of superoxide, hydrogen peroxide, and malondialdehyde; and induced Cd uptake by the roots and leaves. Application of P to Cd-exposed seedlings decreased Cd-induced oxidative stress by enhancing the capacity of ascorbate (AsA) production and ROS-scavenging, and decreased Cd transfer from the roots to the leaves. These results suggest that P application alleviated Cd-induced growth inhibition and oxidative damage by restricting Cd translocation from the roots to the leaves and maintaining sufficient levels of AsA.

• Proceedings of the Korean Society of Crop Science Conference
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• 1990.05a
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• pp.58-59
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• 1990

• Proceedings of the Zoological Society Korea Conference
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• 2003.08a
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• pp.202.1-202
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• 2003

No Abstract, See Full Text

• Proceedings of the Korean Society of Crop Science Conference
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• 1988.02a
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• pp.12-13
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• 1988