• Journal of Ecology and Environment
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• 제30권4호
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• pp.307-314
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• 2007

We studied changes in the biochemical and physiological status and ROS-scavenging enzyme (superoxide dismutase, catalase and peroxidase) activity in leaves and roots of rice (Oryza sativa L.) plants exposed to high salinity. Under salt stress, the reduction in RWC (relative water content) in leaves was relatively severe in comparison with that of roots. The proline content was also significantly higher in leaves of rice plants following salt treatment. The activities of CAT and POX in roots increased with increasing NaCl concentration, but the activity of SOD decreased. These results suggest that the increase of endogenous proline is closely associated with the increase of CAT and POX activities, which may play important roles in salt tolerance. Therefore, we conclude that the alleviation of oxidative damage and increased resistance to salinity may result from the presence of efficient antioxidative systems.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1994년도 춘계 학술대회지
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• pp.78-79
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• 1994

• 생명과학회지
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• 제20권8호
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• pp.1173-1180
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• 2010

Salt stress가 벼 잎 내 광합성 효율과 ascorbate peroxidase (APX) 활성에 미치는 영향을 조사하였다. 염 농도가 증가(NaCl, 100-300 mM) 할수록 Fv/Fm 값이 감소한 반면, $H_2O_2$ 양과 APX 활성은 증가하였다. APX isoforms 중 APX 1 (stromal)은 300 mM NaCl 처리 시 활성이 거의 나타나지 않는 반면, chilling이나 drought 처리 시에는 변화가 없었다. 또한 gel 상에서의 서로 다른 APX isoforms의 활성이 유전자 발현에서도 확인이 되는지를 알아보기 위해 RT-PCR을 수행하였다. 구획별 APX isoforms의 RT-PCR 수행 결과, cytosolic/thylakoid bound APX 발현양은 증가한 반면, stromal APX 발현은 매우 감소하였다. 이러한 실험 결과는 salt에 의해 구획별로 APX 활성이 영향을 받음을 나타낸다.

• 생명과학회지
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• 제23권4호
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• pp.487-494
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• 2013

T-DNA가 표지된 집단에서 AlaAT 유전자가 깨어진 돌연변이체(alaat)를 분리하고, AlaAt1 특이 프라이머를 이용하여 유전자형을 결정하였다. Alaat의 표현형은 대조구와 비교해서 생장의 감소를 보였고, 종자 역시 작고 생산성의 감소를 보였다. 돌연변이체의 AlaAT 활성은 거의 검출되지 않았다. 고염 스트레스 하에서 alaat의 반응을 엽록소 형광과 항산화 효소들의 활성 및 RT-PCR을 이용하여 대조구와 비교하였다. 고염, 건조 및 저온과 같은 모든 비생물적 스트레스에 대한 Fv/Fm은 대조구와 alaat 둘 다 감소를 보였으며, 비생물적 스트레스에 대한 엽록소 형광은 거의 유사하였다. 항산화 효소인 peroxidase (POX)의 활성은 고염 스트레스에 의해 대조구는 증가하나 alaat에서는 오히려 감소하였다. RT-PCR에 의한 cAPX, POX 및 AlaAT mRNA의 수준을 분석한 결과, 효소 활성과 마찬가지로 AlaAt mRNA는 alaat에서 나타나지 않았고, POX2 mRNA는 대조구는 약간의 증가를 보이나 alaat는 거의 검출할 수 없었다. cAPX mRNA는 대조구와 alaat 모두 고염 스트레스에 의해 크게 증가하였다. 이 같은 결과는 AlaAT 유전자 기능의 상실은 염 스트레스 하에서 벼 식물의 생장에 대해 광합성능 보다는 항산화 효소, 특히 POX 활성 및 합성을 변화시킬 수 있음을 제안한다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2023년도 춘계학술대회
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• pp.163-163
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• 2023

• Journal of Plant Biotechnology
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• 제38권1호
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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.

• Journal of Plant Biotechnology
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• 제6권4호
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• pp.205-212
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• 2004

The objectives were to compare the salt tolerance levels in the parental rice cultivar, Dongjinbyeo, and induced mutagenesis derived its lines for plant height, MDA, ATPase, POD, and 2-dimensional protein electrophoresis pattern in NaCl-containing hydroponic nutrient solutions. Rice plants isolated from a population of rice (Oryza sativa L. cv. Dongjinbyeo) mutation lines, which were generated in combination with in vitro selection and gamma-ray, exhibited salt tolerance. Line No. 18 had the longest plant, whereas NaCl-sensitive line (No. 25) had the shortest plant. The parent, and the sensitive line showed severe damage from salt stress. Tolerant lines (No. 18, 50) had a lower malonaldehyde (MDA) content than the sensitive one (Dongjinbyeo, No. 25) during salt stress. Several proteins showed significant quantitative variation through 2DE; phosphoribulokinase, peroxidase, oxygen evolving enhancer 1 and the $H^+-ATPase$, which are known to be involved in salt tolerance. The effect of salt on peroxidase and $H^+-ATPase$ activity in the seedlings of two groups with contrasting genotypes of rice was studied. A greater activity was recorded in the tolerant lines as compared to the sensitive ones (P<0.05, Duncan's test). The results indicate that salt tolerant lines expressed more salt stress-inducible proteins associated with salt tolerance than the sensitive lines during salt stress.

• 생명과학회지
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• 제14권3호
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• pp.396-399
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• 2004

본 실험은 고체배지를 이용한 새로운 실험방법을 이용하여 건조 및 염 스트레스에 대한 식물체의 형태학적인 특성을 뿌리신장률, 근단구조, 물질생산 등의 측면에서 조사하였다. PEG 및 NaCl 처리조건에서 처리 농도가 증가할수록 벼 식물체의 뿌리신장이 현저하게 저하되었으며, PEC 및 NaCl 처리에 따른 벼 식물체의 뿌리는 methyl-lignin 축적에 의한 리그닌화가 진행되었으며, 수분결핍을 극복하려는 기작으로 표피세포를 변형시킨 근모의 발생이 관찰되었다. 또한 PEG 및 NaCl 처리에 의한 벼 식물체의 지상부와 지하부의 건물 생산량의 현저한 감소는 지상부보다 지하부에서 뚜렷하였으며, 그 결과 PEG 및 NaCl 처 처리농도를 증가시킴에 따라 TR율의 증가를 보였다. 상기의 결과로부터 건조 및 염 처리를 한 고체배지를 이용함으로써 벼의 경우 스트레스 처리 전 약 2주간 유묘를 생육시키는 양액재배에 비해 발아기의 각종 스트레스에 대한 식물체 반응의 관찰과 내성 특성 검정에 유용할 것으로 사료된다.

• Journal of Crop Science and Biotechnology
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• 제10권4호
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• pp.257-264
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• 2007

Rice is one of the world's staple crops and is a major source of carbohydrate. Rice is exported from several countries, providing a major source of income. There are many documents reporting that rice is a salt-sensitive crop in its developmental stages. The objective of this investigation is to evaluate the effective salt-tolerance defense mechanisms in aromatic rice varieties. Pathumthani 1(PT1), Jasmine(KDML105), and Homjan(HJ) aromatic rice varieties were chosen as plant materials. Rice seedlings photoautotrophically grown in-vitro were treated with 0, 85, 171, 256, 342, and 427 mM NaCl in the media. Data, including sodium ion$(Na^+)$ and potassium ion$(K^+)$ accumulation, osmolarity, chlorophyll pigment concentration, and the fresh and dry weights of seedlings were collected after salt-treatment for 5 days. $Na^+$ in salt-stressed seedlings gradually accumulated, while $K^+$ decreased, especially in the 342-427 mM NaCl salt treatments. The $Na^+$ accumulation in both salt-stressed root and leaf tissues was positively related to osmolarity, leading to chlorophyll degradation. In the case of the different rice varieties, the results showed that the HJ variety was identified as being salt-tolerant, maintaining root and shoot osmolarities as well as pigment stabilization when exposed to salt stress or $Na^+$ enrichment in the cells. On the other hand, PT1 and KDML105 varieties were classified as salt-sensitive, determined by chlorophyll degradation using Hierarchical cluster analysis. In conclusion, the HJ-salt tolerant variety should be further utilized as a parental line or genetic resource in breeding programs because of the osmoregulation defensive response to salt-stress.

• Molecules and Cells
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• 제24권1호
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• pp.45-59
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• 2007

We describe the gene expression profile of third leaves of rice (cv. Nipponbare) seedlings subjected to salt stress (130 mM NaCl). Transcripts of Mn-SOD, Cu/Zn-SOD, cytosolic and stromal APX, GR and CatB were up-regulated, whereas expression of thylakoid-bound APX and CatA were down-regulated. The levels of the compatible solute proline and of transcripts of its biosynthetic gene, ${\Delta}^1$-pyrroline-5-carboxylate synthetase (P5CS), were strongly increased by salt stress. Interestingly, a potential compatible solute, ${\gamma}$-aminobutyric acid (GABA), was also found to be strongly induced by salt stress along with marked up-regulation of transcripts of GABA-transaminase. A dye-swap rice DNA microarray analysis identified a large number of genes whose expression in third leaves was altered by salt stress. Among 149 genes whose expression was altered at all the times assayed (3, 4 and 6 days) during salt stress, there were 47 annotated novel genes and 76 unknown genes. These results provide new insight into the effect of salt stress on the expression of genes related to antioxidant enzymes, proline and GABA as well as of genes in several functional categories.