• The Plant Pathology Journal
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• v.31 no.2
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• pp.192-194
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• 2015

Pathogen-associated molecular patterns (PAMPs) activate mitogen-activated protein kinases (MAPKs), essential components of plant defense signaling. Salicylic acid (SA) is also central to plant resistance responses, but its specific role in regulation of MAPK activation is not completely defined. We have investigated the role of SA in PAMP-triggered MAPKs pathways in Arabidopsis SA-related mutants, specifically in the flg22-triggered activation of MPK3 and MPK6. cim6, sid2, and npr1 mutants exhibited wild-type-like flg22-triggered MAPKs activation, suggesting that impairment of SA signaling has no effect on the flg22-triggered MAPKs activation. Pretreatment with low concentrations of SA enhanced flg22-induced MPK3 and MPK6 activation in all seedlings except npr1, indicating that NPR1 is involved in SA-mediated priming that enhanced flg22-induced MAPKs activation.

• Journal of Plant Biotechnology
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• v.49 no.4
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• pp.300-306
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• 2022

The mitogen-activated protein kinase (MAPK) signaling cascade is essential for a wide range of cellular responses in plants, including defense responses, responses to abiotic stress, hormone signaling, and developmental processes. Recent investigations have shown that the stress, ethylene, and MAPK signaling pathways negatively affect the formation of nitrogen-fixing nodules by directly modulating the symbiotic signaling components. However, the molecular mechanisms underlying the defense responses mediated by MAPK signaling in the organogenesis of nitrogen-fixing nodules remain unclear. In the present study, I demonstrate that the Medicago truncatula mitogen-activated protein kinase kinase 5 (MtMKK5)-Medicago truncatula mitogen-activated protein kinase 3/6 (MtMPK3/6) signaling module, expressed specifically in the symbiotic nodules, promotes defense signaling, but not ethylene signaling pathways, thereby inhibiting nodule development in M. truncatula. U0126 treatment resulted in increased cell division in the nodule meristem zone due to the inhibition of MAPK signaling. The phosphorylated TEY motif in the activation domain of MtMPK3/6 was the target domain associated with specific interactions with MtMKK5. I have confirmed the physical interactions between M. truncatula nodule inception (MtNIN) and MtMPK3/6. In the presence of high expression levels of the defense-related genes FRK1 and WRKY29, MtMKK5a overexpression significantly enhanced the defense responses of Arabidopsis against Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Overall, my data show that the negative regulation of symbiotic nitrogen-fixing nodule organogenesis by defense signaling pathways is mediated by the MtMKK5-MtMPK3/6 module.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.701-707
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• 2003

Kimchi was prepared with the addition of 2.5％ and 5.0％ Monascu purpureu koji(MPK) paste (20％) and were fermented at 20$^{\circ}C$ for 18 days. The quality and sensory characteristics of the kimchi were evaluated by analyzing the pH, acidity, number of viable cells, the concentration of reducing sugar, and sensory properties during fermentation. The pH and titratable acidity of the kimchiprepared with MPK(MPK kimchi) were higher and lower, respectively, than those of the control kimchi. The MPK kimchi showed high 'L' and 'b' values during storage, but the 'a' values were low. The contents of the reducing sugar of the MPK kimchi tended to increase during fermentation, particularly after six days. The number of total microbial cells, lactic acid bacteria and yeast in the MPK kimchi were lower than those of the control kimchi until 3 days of fermentation. However, the number of these bacteria in the MPK kimchi and the control kimchi after six days of fermentation was similar. The sensory score of the kimchi with 2.5％ and 5.0％ added MPK paste were significantly higher than the control groups in terms of the sweetness and overall acceptability.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.148.1-148.1
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• 2014

포항가속기연구소는 Dipole Magnet, Wiggler, Undulator 등 다양한 광원에서 발생되는 강한 방사광을 여러 연구에 이용하고 있다. Max-Planck POSTECH 분원용 타원편광 Undulator (이하, MPK-EPU)는 carbon의 흡수선을 포함하는 250 eV에서 시작하여, 1,500 eV~3,000 eV 에너지 영역의 방사광을 발생시켜 자성물질을 비롯한 다양한 이방성 물질의 연구를 수행하는데 활용할 예정이다. 현재, MPK-EPU용 진공용기의 기계가공, 화학세척, 용접 및 최종 초고진공 진공 달성을 위한 탈기체처리, NEG 활성화 작업등을 마무리하고 PLS-II 저장링 6A 구간에 설치 완료하였다. 이 논문에서는 MPK-EPU용 진공시스템의 제작 및 설치작업에 대한 전반적인 사항과 진공작업 및 그 결과를 발표하고자 한다.

• Proceedings of the Korean Society of Life Science Conference
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• 2005.04a
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• pp.23-36
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• 2005

Bax, a mammalian pro-apoptotic member of the Bcl-2 family, induces cell death when expressed In yeast. To investigate whether .Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various orgarusms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs In detail. PBIl is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Bax-induced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower lovels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. H$_{2O2}$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of H2O2 treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased In the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MBP phosphorylation activity of AtMPK3 i'n vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation In situ. Thus, AtNDPK2 appears to play a novel regulatory role in H2O2-mediated MAPK signaling in plants.

• Molecules and Cells
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• v.40 no.1
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• pp.17-23
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• 2017

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.

• Korean Journal of Food Science and Technology
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• v.37 no.4
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• pp.618-623
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• 2005

Kimchi was prepared with 2.5% and 5% Monascus purpureus Koji(MPK) paste(20%), fermented at $10^{\circ}C$ for 15 days, and sampled at 3-day intervals during storage. Samples were extracted using 80% ethanol. Ethanol extracts of kimchi prepared with MPK paste (MPK kimchi extracts) and control kimchi extracts at 1mg/mL showed 40% decrease in proliferation of cancer cells, such as AGS, KATOIII, HepG2, and Hela. MPK kimchi extracts showed highest cytotoxic effect against cancer cells compared with control at 2mg/mL. Antibacterial effect of MPK kimchi extracts decreased during fermentation, and was higher than that of control kimchi extracts during fermentation, particularly after six days. The 5% MPK kimchi extracts showed higher antibacterial activity against Escherichia coli O157:H7 and Vibrio parahaemolyticus than other groups. Results indicate kimchi added with M. purpureus Koji paste has stronger antibacterial and anticancer effects in vitro than control kimchi.

• Journal of Plant Biotechnology
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• v.5 no.3
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• pp.143-148
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• 2003

Bax, a mammalian pro-apoptotic member of the Bcl-2 family induces cell death when expressed in yeast. To investigate whether Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various organisms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs in detail. PBI1 is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Baxinduced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower levels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. $H_2O_2$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of $H_2O_2$ treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased in the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MSP phosphorylation activity of AtMPK3 in vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation in situ. Thus, AtNDPK2 appears to playa novel regulatory role in $H_2O_2$-mediated MAPK signaling in plants.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2003.04a
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• pp.65-71
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• 2003

Bax, a mammalian pro-apoptotic member of the Bcl-2 family, induces cell death when expressed in yeast. To investigate whether Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various organisms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs in detail. PBI1 is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorho-damine 123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Baxinduced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower levels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. $H_2O_2$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of $H_2O_2$ treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased in the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MBP phosphorylation activity of AtMPK3 in vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation in situ. Thus, AtNDPK2 appears to play a novel regulatory role in $H_2O_2$-mediated MAPK signaling in plants.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.82-83
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• 2003

Plants have evolved differently from animals having mobile activities. Thus, plants should have developed unique defense mechanisms against biotic/abiotic stresses to which plants are differently exposed, according to seasons. Most organisms have an conserved signaling network using mitogen-activated protein kinase (MAPK) cascade(s). The phenomenon implied that they are functionally very important in all organisms. In fact, they constitute one of the major components of signaling pathways involved in regulating a wide range of cellular activities from growth and development to cell death. Recently, complete MAPK cascade was first characterized in Arabidopsis from the receptor kinase (FLS2) through fellowing MEKKI -MKK4/MKK5-MPK3/MPK6-WRKY22/MRKY29 pathway. Whereas, MAPK cascade signaling pathway in monocot plant including rice (0ryza sativa L.), the most important of all food crops and an established monocot plant research model, MAPKinase kinase kinases (MAPKKK) of rice are the first upstream component of the MAPK cascade, but MAPKKK has been first identified and characterized in our lab and designated as, OsEDRl based on its homology with the Arabidopsis EDRI. The Arabidopsis EDRl was regarded as a negative regulator of defense response and the role of rice OsEDRl was analyzed. Transcriptional regulation of OsEDRl was detected under various stresses and immunoblotting analysis is going on to detect the level of OsEDRl protein in the mutants showing unique phenotype. We also introduced the constitutively active and the dominant negative forms of the OsEDRl for characterizing biological function.