• Journal of Ginseng Research
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• v.44 no.2
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• pp.332-340
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• 2020

Background: The valuable medicinal plant Panax ginseng has high pharmaceutical efficacy because it produces ginsenosides. However, its yields decline because of a root-rot disease caused by Ilyonectria mors-panacis. Because species within Ilyonectria showed variable aggressiveness by altering ginsenoside concentrations in inoculated plants, we investigated how such infections might regulate the biosynthesis of ginsenosides and their related signaling molecules. Methods: Two-year-old ginseng seedlings were treated with I. mors-panacis and I. robusta. Roots from infected and pathogen-free plants were harvested at 4 and 16 days after inoculation. We then examined levels or/and expression of genes of ginsenosides, salicylic acid (SA), jasmonic acid (JA), and reactive oxygen species (ROS). We also checked the susceptibility of those pathogens to ROS. Results: Ginsenoside biosynthesis was significantly suppressed and increased in response to infection by I. mors-panacis and I. robusta, respectively. Regulation of JA was significantly higher in I. robusta-infected roots, while levels of SA and ROS were significantly higher in I. mors-panacis-infected roots. Catalase activity was significantly higher in I. robusta-infected roots followed in order by mock roots and those infected by I. mors-panacis. Moreover, I. mors-panacis was resistant to ROS compared with I. robusta. Conclusion: Infection by the weakly aggressive I. robusta led to the upregulation of ginsenoside production and biosynthesis, probably because only a low level of ROS was induced. In contrast, the more aggressive I. mors-panacis suppressed ginsenoside biosynthesis, probably because of higher ROS levels and subsequent induction of programmed cell death pathways. Furthermore, I. mors-panacis may have increased its virulence by resisting the cytotoxicity of ROS.

• Journal of Crop Science and Biotechnology
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• v.10 no.2
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• pp.112-116
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• 2007

Kinetin(KN) is an inducer of rice(Oryza sativa L.) defense/stress responses, as evidenced by the induction of inducible secondary metabolite and defense/stress protein markers in leaf. We show a novel light-dependent effect of KN-triggered defense stress responses in rice leaf. Leaf segments treated with KN(100 ${\mu}M$) show hypersensitive-like necrotic lesion formation only under continuous light illumination. Potent accumulation of two phytoalexins, sakuranetin and momilactone A(MoA) by KN that peaks at 48 h after treatment under continuous light is completely suppressed by incubation under continuous dark. Using two-dimensional gel electrophoresis we identified KN-induced changes in ribulose-1, 5-bisphosphate carboxylase/oxygenase, energy- and pathogenesis-related proteins(OsPR class 5 and 10 members) by N-terminal amino acid sequencing and mass spectrometry. These changes were light-inducible and could not be observed in the dark(and control). Present results provide a new dimension(light modulation/regulation) to our finding that KN has a potential role in the rice plant self-defense mechanism.

• The Korean Journal of Pesticide Science
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• v.18 no.4
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• pp.422-428
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• 2014

Endophytic bacterial strains from root tissue of strawberry were screened for their efficacy in growth improvement and control of Phytophthora blight disease of chili pepper plant under greenhouse condition. Plants treated with the strain EP103, identified as Pseudomonas fluorescens, showed growth improvement in terms of fresh weight and root length compared to the untreated control and other endophytic strains. When challenged with Phytophthora capsici, there was significant reduction of disease in EP103 treated plants with an efficacy of 78.7%. There was no direct inhibition of the target pathogen by EP103 when tested under in vitro antibiosis assay. Analysis of differential expression of selected marker genes for induced systemic resistance (ISR) in plants treated with EP103 and challenged with P. capsici showed up-regulation of PR1 and PR10 pathogenesis-related (PR) proteins. PCR analysis showed that EP103 produced secondary metabolites such as pyoluteorin, pyrrolnitrin, hydrogen cyanide and orfamide A. This study indicated the potential of endophytic P. fluorescens strain EP103 as an efficient biocontrol agent against P. capsici in chili pepper plant.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.32 no.3 s.58
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• pp.135-140
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• 2006

Nuclear factor-kappaB (NF-kappaB) is a critical transcription factor for maximal expression of many of the cytokines that are involved in the pathogenesis of inflammatory diseases. In this study, we found that 12 plant extracts among 200 plants, namely, Forsythia koreana, Capsicum annuum L, Mentha arvenis, Duchesnea chrysantha, Morus alba, Saururus Chinenis (Lour) Baill, Pine needle, Zingiber mioga (Thunb.), Roscoe, Houttuynia, Prunus yedoenis, Sasa quelpaertenis, significantly inhibited LPS- induced NF-kappaB activation in a concentration-dependent manner. Additionally, 12 plant extracts were found to have antioxidant activities in DPPH assay Therefore, we have attempted to determine whether 12 herbal extracts could inhibit the expression of cytokines possessing NF-kappaB promoter in their promoter regions. Consistently 12 herbal extracts inhibited LPS-induced production of TNF alpha and interleukin-8 (IL-8). These results show that 12 herbal extracts suppresses the production of pro-inflammatory mediators through the inhibition of the NF-kappaB signaling pathway, we suggest that 12 herbal extracts can be used as a anti-inflammatory and soothing agent.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.265-272
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• 2006

Acne is a chronic inflammatory follicular disorder of the skin, occurring in specialized pilosebaceous units on the face, and Propionibacterium acnes, a strict anaerobic pathogen, plays an important role in the pathogenesis of acne. To develop a reliable and effective anti-acne agent, we have evaluated antibacterial activity of 500 plant extracts, prepared from 335 plants, against P. acnes. Based on the results of disc-paper method, 25 plant extracts, including the extracts of Chloranthus japonicus (aerial part), Sophora flavescens (radix), Evodia officinalis (fructus), Ginko biloba (semem), Morus alba (root bark), Aralia continentalis (whole) and Reynoutria elliptica (radix), were selected as possible sources of anti-acne agent. Among them, the extract of S. flavescens (radix) was finally selected and kuraridin and kurarinone were identified as major active compounds of S. flavescens. These results suggested that medicinal and wild plants could be the potential source of anti-acne agent.

• Research in Plant Disease
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• v.16 no.3
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• pp.274-278
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• 2010

Potato late blight caused by Phytophthora infestans was the most constrain disease at potato cultivation areas. The mating type distribution and fungicides response of P. infestans were investigated to elucidate the changes of pathogen from Gangwon province. On the fungal isolates in 2006, 58.7% were A1 mating type and 41.3% were A2 mating type. In 2007, A1 mating type isolates increased to 93.3% and A2 mating type isolates were collected from Jinbu areas as much as 6.7%. About 234 isolates analysed for metalaxyl response, the results was resistance 73.7%, intermediate 18.8% and sensitive 7.5% in 2006. And it was resistance 59.4%, intermediate 4.0% and sensitive 36.6% in 2007. It meant that mating type distribution and fungicide response were very different over the collection sites. Minimal inhibition concentration (MIC) of dimethomorph examined with 126 isolates in 2006 and 106 isolates in 2007. MIC over $1.0\;{\mu}g/ml$ was 56.3% in 2006 and it was 3.8% in 2007. The average $EC_{50}$ value of P. infestans was $0.37\;{\mu}g/ml$ in 2006, but it decreased to $0.12\;{\mu}g/ml$ in 2007. Fungicides response and pathogenesis of P. infestans should be monitored continuously to enhance the chemical efficacy at potato fields.

• Journal of Life Science
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• v.30 no.3
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• pp.285-290
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• 2020

Foot-and-mouth disease virus (FMDV), a member of the genus Aphthovirus in the Picornaviridae family, affects wild and domesticated ruminants and pigs. FMDV causes various clinical symptoms, including severe inflammation in infected tissue. Genome RNA of FMDV shows a positive single-strand chain approximately 8.3 kb long and encodes a single long open reading frame (ORF). The ORF is translated into structural and non-structural proteins by viral proteases. The FMDV 2C protein is one of the non-structural proteins encoded by FMDV and plays a critical role in FMD pathogenesis, including inflammation, apoptosis, and viral replication. In this study, we examined whether FMDV 2C induces intracellular expression of pro-inflammatory cytokine tumor necrosis factor alpha (TNFα). FMDV 2C expression in pig IBRS-2 cells increased mRNA and protein expression of TNFα at the transcriptional level via activation of TNFα promoter. Treatment with 4-phenylbutyric acid, an endoplasmic reticulum (ER) stress reducer, decreased TNFα expression induced by FMDV 2C. Activating transcription factor 4 (ATF4), a transcription factor mediating ER stress response, induced transactivation of TNFα promoter and expression of mRNA and protein of TNFα. However, the dominant negative mutant of ATF4 did not induce FMDV 2C-mediated TNFα expression. The results indicate that FMDV 2C protein increases clinical inflammation via ATF4-mediated TNFα expression and is associated with ER stress induction.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.49-54
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• 1995

To understand the molecular structure and pathogenesis mechanism of Korean garlic viruses, we have isolated cDNA clones for garlic viruses. The partial nucleotide sequences of 24 cDNA clones were determined and those of five clones containing poly(A) tail were compared with sequences of other plant viruses. One of these clones, V9, has a primary structure similar to the carlavirus group, suggesting that the clone V9 derived from a part of garlic latent virus (GLV). Northern blot analysis with the clone V9 as a probe demonstrated that GLV genome is 8.5 knt long and has a poly(A) tail. The clone V9 encodes coat protein (CP) of 33 kDa and nucleic acid binding protein of 10 kDa in different reading frame. The hexanucleotide motif, 5'-ACCUAA, which is conserved in the 3' noncoding region arid was proposed to be a cis-acting element involved in the production of negative strand genomic RNA was noticed. Complementary sequence to the hexanucleotide motif, 5'-TTAGGT, is also found in the positive strand of V9 RNA. The putative CP gene was cloned into the pRSET-A expression vector and expressed in E. coli BL21. The expressed recombinant V9CP protein was purified by $Ni^{2+}$ NTA affinity chromatography. The anti-V9CP antibody recognizes 34 kDa polypeptide which could be CP of GLV in infected garlic leaf extract. Immunoblot and Northern blot analysis of various cultivars shows wide occurrence of GLV in Korean garlic plants.

• Journal of Life Science
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• v.25 no.2
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• pp.136-150
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• 2015

Pseudomonas syringae pathovar tabaci is a plant pathogenic bacterium that causes wildfire disease in tobacco plants. In P. syringae pv. tabaci, PsyI, a LuxI-type protein, acts as an AHL synthase, while primary and secondary sequence analysis of PsyR has revealed that it is a homolog of the LuxR-type transcriptional regulator that responds to AHL molecules. In this study, using phenotypic and genetic analyses in P. syringae pv. tabaci, we show the effect of PsyR protein as a quorum-sensing (QS) transcriptional regulator. Regulatory effects of PsyR on swarming motility and production of siderophores, tabtoxin, and N-acyl homoserine lactones were examined via phenotypic assays, and confirmed by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Further qRT-PCR showed that PsyR regulates expression of these virulence genes in response to environmental signals. However, an upstream region of the gene was not bound with purified MBP-PsyR protein; rather, PsyR was only able to shift the upstream region of psyI. These results suggested that PsyR may be indirectly controlled via intermediate-regulatory systems and that auto-regulation by PsyR does not occur.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.1
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• pp.15-20
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• 2006

Biological control by chitinolytic microorganisms is being evaluated as management options for soilborne diseases. Forty kilograms of chitin compost (CTC) and control compost (CC) were amended on tomato plots ($15m{\times}0.5m$) 7 d before transplanting to evaluate enzymatic activities and the control of Fusarium wilt. Samples were taken on day 1, 3, 5, and 7, the day 1 corresponded to the 66 d after transplanting, the day on which the initial wilting symptoms occurred in plants of CC treated plots. The chitinase activity in soil of CTC was always higher compared to the control. Pathogenesis related (PR) protein (chitinase, ${\beta}$-1, 3-glucanase and peroxidase) activities in tomato roots in CC increased every day and showed marked differences compared to CTC. Wilting symptoms (96 d after transplanting) were reduced by 25% in CTC compared to the control. Protection of tomato plant may be correlated with the high levels of soil enzyme activities resulting from the chitin compost.