• The Plant Pathology Journal
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• v.22 no.4
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• pp.360-363
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• 2006

Efficacy of plant growth promoting rhizobacteria(PGPR) Bacillus vallismortis strain EXTN-1 has been proved in eliciting induced systemic resistance(ISR) in several crops. The present paper described the beneficial effects of EXTN-1 in potato as increase in yield and chlorophyll content, and plant protection against Potato Virus Y and X(PVY & PVX). EXTN-1 induced systemic resistance to the plants resulting in significant disease suppression in the field. Also the plants under treatment with EXTN-1 had higher chlorophyll content. The bacterized plants had significantly higher yields over the untreated control plants. The strain induced activation of defense genes, PR-1a and PDF 1.2 in transgenic tobacco model, which indicated the possible role of both SA, and JA pathways in EXTN-1 mediated plant protection against crop diseases.

• The Plant Pathology Journal
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• v.28 no.3
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• pp.322-329
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• 2012

This study was conducted to investigate host and non-host disease resistances of kimchi cabbage plants to bacterial infection. Kimchi cabbage leaves responded differently to infections with a virulent strain of Xanthomonas campestris pv. campestris (Xcc) 8004 and two strains (85-10 and Bv5-4a.1) of non-host bacteria X. campestris pv. vesicatoria (Xcv). Non-host bacteria triggered a rapid tissue collapse of the leaves showing as brown coloration at the infected sites, highly increased ion leakage, lipid peroxidation and accumulation of UV-stimulated autofluorescence materials at the inoculated sites. During the observed interactions, bacterial proliferations within the leaf tissues were significantly different. Bacterial number of Xcc 8004 progressively increased within the inoculated leaf tissues over time, while growths of two non-host bacteria Xcv strains were distinctly limited. Expressions of pathogenesis-related genes, such as GST1, PR1, BGL2, VSP2, PR4 and LOX2, were differentially induced by host and non-host bacterial infections of X. campestris pathovars. These results indicated that rapid host cellular responses to the non-host bacterial infections may contribute to an array of defense reactions to the non-host bacterial invasion.

• International Journal of Industrial Entomology and Biomaterials
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• v.17 no.2
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• pp.223-228
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• 2008

A novel beetle antimicrobial protein from stimulated Copris tripartitus and the corresponding gene were isolated in parallel through differential display-PCR and expression in Escherichia coli. To find cDNA clones responsible for bacteria resistance, the suppression subtractive hybridization and GeneFishing differentially expressed genes system were employed in the dung beetle, Copris tripartitus immunized with lipopolysaccaride. One cDNA clone from eight subtracted clones was selected through dot blot analysis and confirmed by northern blot analysis. The 516-bp, selected cDNA clone was determined by 5' and 3' rapid amplication of cDNA ends and cloned into the GST fusion expression vector pGEX-4T-1 for expression of the protein. The expressed protein was predicted 14.7 kDa and inhibited the growth of gram-negative bacteria such as Escherichia coli and Pseudomonas aeruginosa. These results implied that the expressed protein is related to immune defense mechanism against microorganism.

• Molecular & Cellular Toxicology
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• v.5 no.1
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• pp.1-6
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• 2009

Microglial cells constitute the first line of defense against infection and injury in the brain. This study was conducted to evaluate the protective mechanisms of Agrimonia pilosa (AP) on LPS-induced activation of BV-2 microglial cells. The effects of AP on gene expression profiles in activated BV-2 microglial cells were evaluated using microarray analysis. BV-2 microglial cells were cultured in a 100 mm dish ($1{\times}10^7/mL$) for 24 hr and then pretreated with 1 g/mL AP or left untreated for 30 min. Next, 1 g/mL LPS was added to the samples and the cells were reincubated at $37^{\circ}C$ for 30 min, 3 hr and 6 hr. The gene expression profiles of the BV-2 microglial cells varied depending on the AP. The microarray analysis revealed that MAPK signaling pathway-related genes were down-regulated and IL10 gene was up-regulated in AP-treated BV-2 microglial cells. AP can affect the inflammatory response and MAPK pathway in BV-2 microglial cells.

• ALGAE
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• v.27 no.1
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• pp.21-32
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• 2012

We report an oxidative burst triggered by prostaglandin $A_2(PGA_2)$ in the brown algal kelp Laminaria digitata, constituting the first such discovery in an alga and the second finding of an oxidative burst triggered by a prostaglandin in a living organism. The response is more powerful than the oxidative burst triggered by most other chemical elicitors in Laminaria. Also, it is dose-dependent and cannot be inhibited by diphenylene iodonium, suggesting that another source than NAD(P)H oxidase is operational in the production of reactive oxygen species. Despite the very strong oxidative response, rather few effects at other levels of signal transduction pathways could be identified. $PGA_2$ does not increase lipolysis (free fatty acids) in Laminaria, and only one oxylipin (15-hydroxyeicosatetraenoic acid; 15-HETE) was found to be upregulated in Laminaria. In a subsequent set of experiments in the genome model Ectocarpus siliculosus, none of 5 selected candidate genes, all established participants in various stress responses, showed any significant differences in their expression profiles.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.471-476
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• 2013

Plants are frequently exposed to numerous environmental stresses such as dehydration and high salinity, and have developed elaborate mechanisms to counteract the deleterious effects of stress. The phytohormone abscisic acid (ABA) plays a critical role as an integrator of plant responses to water-limited condition to activate ABA signal transduction pathway. Although perception of ABA has been suggested to be important, the function of each ABA receptor remains elusive in dehydration condition. Here, we show that ABA receptor, pyrabactin resistance-like protein 8 (PYL8), functions in dehydration conditions. Transgenic plants overexpressing PYL8 exhibited hypersensitive phenotype to ABA in seed germination, seedling growth and establishment. We found that hypersensitivity to ABA of transgenic plants results in high degrees of stomatal closure in response to ABA leading to low transpiration rates and ultimately more vulnerable to drought than the wild-type plants. In addition, high expression of ABA maker genes also contributes to altered drought tolerance phenotype. Overall, this work emphasizes the importance of ABA signaling by ABA receptor in stomata during defense response to drought stress.

• BMB Reports
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• v.50 no.1
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• pp.31-36
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• 2017

High-dose caffeine uptake is a developmental stressor and causes food-avoidance behavior (aversion phenotype) in C. elegans, but its mode of action is largely unknown. In this study, we investigated the molecular basis of the caffeine-induced aversion behavior in C. elegans. We found that aversion phenotype induced by 30 mM caffeine was mediated by JNK/MAPK pathway, serotonergic and dopaminergic neuroendocrine signals. In this process, the dopaminergic signaling appears to be the major pathway because the reduced aversion behavior in cat-2 mutants and mutants of JNK/MAPK pathway genes was significantly recovered by pretreatment with dopamine. RNAi depletion of hsp-16.2, a cytosolic chaperone, and cyp-35A family reduced the aversion phenotype, which was further reduced in cat-2 mutants, suggesting that dopaminergic signal is indeed dominantly required for the caffeine-induced food aversion. Our findings suggest that aversion behavior is a defense mechanism for worms to survive under the high-dose caffeine conditions.

• The Plant Pathology Journal
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• v.36 no.2
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• pp.121-132
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• 2020

β-Aminobutyric acid (BABA) has consistently been reported to enhance plant immunity. However, the specific mechanisms and downstream components that mediate this resistance are not yet agreed upon. Nitric oxide (NO) is an important signal molecule involved in a diverse range of physiological processes, and whether NO is involved in BABA-induced resistance is interesting. In this study, treatment with BABA significantly increased NO accumulation and reduced the sensitivity to Botrytis cinerea in tomato plants. BABA treatment reduced physical signs of infection and increased both the transcription of key defense marker genes and the activity of defensive enzymes. Interestingly, compared to treatment with BABA alone, treatment with BABA plus cPTIO (NO specific scavenger) not only significantly reduced NO accumulation, but also increased disease incidence and lesion area. These results suggest that NO accumulation plays an important role in BABA-induced resistance against B. cinerea in tomato plants.

• Molecules and Cells
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• v.28 no.4
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• pp.365-368
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• 2009

Toll-like receptors (TLRs) play an important role in host defense by sensing invading microbial pathogens and initiating innate immune responses. The stimulation of TLRs by microbial components triggers the activation of myeloid differential factor 88 (MyD88)- and toll-interleukin-1 receptor domain-containing adapter inducing interferon-${\beta}$ (TRIF)-dependent downstream signaling pathways. Isoliquiritigenin (ILG), an active ingredient of Licorice, has been used for centuries to treat many chronic diseases. ILG inhibits the MyD88-dependent pathway by inhibiting the activity of inhibitor-${\kappa}B$ kinase. However, it is not known whether ILG inhibits the TRIF-dependent pathway. To evaluate the therapeutic potential of ILG, we examined its effect on signal transduction via the TRIF-dependent pathway of TLRs induced by several agonists. ILG inhibited nuclear factor-${\kappa}B$ and interferon regulatory factor 3 activation induced by lipopolysaccharide or polyinosinic-polycytidylic acid. ILG inhibited the lipopolysaccharide-induced phosphorylation of interferon regulatory factor 3 as well as interferon-inducible genes such as interferon inducible protein-10, and regulated activation of normal T-cell expressed and secreted (RANTES). These results suggest that ILG can modulate TRIF-dependent signaling pathways of TLRs, leading to decreased inflammatory gene expression.

• Molecules and Cells
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• v.26 no.3
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• pp.270-277
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• 2008

This study addresses the physiological functions of the Ran-binding protein homolog NbRanBP1 in Nicotiana benthamiana. Virus-induced gene silencing (VIGS) of NbRanBP1 caused stunted growth, leaf yellowing, and abnormal leaf morphology. The NbRanBP1 gene was constitutively expressed in diverse tissues and an NbRanBP1:GFP fusion protein was primarily localized to the nuclear rim and the cytosol. BiFC analysis revealed in vivo interaction between NbRanBP1 and NbRan1 in the nuclear envelope and the cytosol. Depletion of NbRanBP1 or NbRan1 reduced nuclear accumulation of a NbBTF3:GFP marker protein. In the later stages of development, NbRanBP1 VIGS plants showed stress responses such as reduced mitochondrial membrane potential, excessive production of reactive oxygen species, and induction of defense-related genes. The molecular role of RanBP1 in plants is discussed in comparison with RanBP1 function in yeast and mammals.