• IMMUNE NETWORK
• /
• v.20 no.6
• /
• pp.49.1-49.15
• /
• 2020

C-C chemokine receptor type 5 (CCR5) regulates the trafficking of various immune cells to sites of infection. In this study, we showed that expression of CCR5 and its ligands was rapidly increased in the kidney after systemic Candida albicans infection, and infected CCR5^-/- mice exhibited increased mortality and morbidity, indicating that CCR5 contributes to an effective defense mechanism against systemic C. albicans infection. The susceptibility of CCR5^-/- mice to C. albicans infection was due to impaired fungal clearance, which in turn resulted in exacerbated renal inflammation and damage. CCR5-mediated recruitment of NK cells to the kidney in response to C. albicans infection was necessary for the anti-microbial activity of neutrophils, the main fungicidal effector cells. Mechanistically, C. albicans induced expression of IL-23 by CD11c⁺ dendritic cells (DCs). IL-23 in turn augmented the fungicidal activity of neutrophils through GM-CSF production by NK cells. As GM-CSF potentiated production of IL-23 in response to C. albicans, a positive feedback loop formed between NK cells and DCs seemed to function as an amplification point for host defense. Taken together, our results suggest that CCR5-mediated recruitment of NK cells to the site of fungal infection is an important step that underlies innate resistance to systemic C. albicans infection.

• The Korean Journal of Pesticide Science
• /
• v.17 no.4
• /
• pp.394-401
• /
• 2013

Trichoderma harzianum is one of rhizosphere fungus usually lives near the plant root regions in the soil. T. harzianum plays an important role in plant growth promotion and increases disease resistance against various plant pathogens on crops. In this study, the strain T. harzianum MPA167 was isolated from the barley rhizosphere soil in Suwon, Korea. Among 183 isolates, the strain T. harzianum MPA167 was selected as promising strain in which based on hyperparasitical activity against Phytophthora capsici and estimated disease control activity against P. capsici in the greenhouse conditions. The strain T. harzianum MPA167 was identified using 23s rDNA internal transcribed spacer(ITS) region sequences. MPA167 treatment ($1{\times}10^6$ spores/ml) showed greater disease suppression against Phytophthora blight of red-pepper caused by P. capsici in greenhouse compared with the water-treated control. Volatiles derived from T. harzianum MPA167 elicit growth promotion of tobacco and Arabidopsis seedlings in I-plate assay. In addition, T. harzianum MPA167 strain was also found to be effective for the growth promotion and induction of systemic resistance on red-papper plant. These results suggest that MPA167 might be used as one of the potential biocontrol agents.

• Mycobiology
• /
• v.32 no.1
• /
• pp.47-53
• /
• 2004

Pseudomonas fluorescens 1-94 induced systemic resistance in chickpea against Fusarium wilt of chickpea caused by Fusarium oxysporum f. sp. ciceri by the synthesis and accumulation of phenolic compounds, phenylalanine ammonia lyase(PAL) and pathogenesis related(PR) proteins(chitinase, $\beta$-1,3-glucanase and peroxidase). Time-course accumulation of these enzymes in chickpea plants inoculated with P. fluorescens was significantly(LSD, P=0.05) higher than control. Maximum activities of PR-proteins were recorded at 3 days after inoculation in all induced plants; thereafter, the activity decreased progressively. Five PR peroxidases detected in induced chickpea plants. Molecular mass of these purified peroxidases was 20, 29, 43, 66 and 97 kDa. Purified peroxidases showed antifungal activity against plant pathogenic fungi.

• Proceedings of the Korean Society of Plant Pathology Conference
• /
• 2003.10a
• /
• pp.69.1-69
• /
• 2003

RSH (relA/spoT homolog) has been known to determine the level of guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp), which are the effector nucleotide of the prokaryotic stringent response and also play a role in antibiotic production and differentiation in Streptomyces species but not a little in eukaryotic organism, especially in plant. Salicylic acid (SA), a critical signal molecule of establishing systemic acquired resistance (SAR), could induce SAR in Pepper (Capcicum annuum) against Phytophthora capsici. And the extent of SAR induction was in proportion to the dosage of SA (or BTH). Suppression subtractive hybridization (SSH), a PCR-based method for cDNA subtraction, was carried out between SA-treated and non-SA-treated pepper leaves to isolate genes which may be responsible for defense signaling against pathogens. Early upregulated gene was selected from reverse northern and kinetics of SSH-genes transcripts in SA-treated pepper leaves upon SA treatment. Full-length cDNA of the gene (PepRSH； Pepper RelA / SpoT homolog) had an open reading frame (ORF) of 2166 bp encoding a protein of 722 amino acids and a significant homology with (p)ppGpp phosphohydrolase or synthetase. Genomic DNA gel blot analysis showed that pepper genome has at least single copy of PepRSH. PepRSH transcripts was very low in untreated pepper leaves but strongly induced by SA and methyljasmonic acid (MeJA), indicating that PepRSH may share common SA and MeJA-mediated signal transduction pathway Functional analysis in E. coli showed PepRSH confers phenotypes associated with (p)ppGpp synthesis through a complementation using active site mutagenesis.

• Korean Journal of Microbiology
• /
• v.53 no.4
• /
• pp.329-331
• /
• 2017

Bacillus velezensis YC7010 is an endophytic bacterium isolated from the rice rhizosphere in Jinju, Republic of Korea, with properties conductive to growth promotion, antibiosis and induced systemic resistance to significant, soil-borne rice fungal and bacterial pathogens. The genome of B. velezensis YC7010 comprises a 3,975,683 bp circular chromosome which consists of 3,790 protein-coding genes (86tRNA and 27rRNA genes). Based on genomic analysis, we identified genes involved in colonization and establishment inside the plant, biosynthesis of antibiotic compounds such as surfactin, plipapastatin, bacillibactin, and bacillaene, as well as the production of the phytohormones and volatile compounds which serve to promote the plants growth and development.

• The Plant Pathology Journal
• /
• v.35 no.3
• /
• pp.208-218
• /
• 2019

Here, we reported a novel secreted protein elicitor PeBL2 from Brevibacillus laterosporus A60, which can induce hypersensitive response in tobacco (Nicotiana benthamiana). The ion-exchange chromatography, high-performance liquid chromatography (HPLC) and mass spectrometry were performed for identification of protein elicitor. The 471 bp PeBL2 gene produces a 17.22 kDa protein with 156 amino acids containing an 84-residue signal peptide. Consistent with endogenous protein, the recombinant protein expressed in Escherichia coli induced the typical hypersensitive response (HR) and necrosis in tobacco leaves. Additionally, PeBL2 also triggered early defensive response of generation of reactive oxygen species ($H_2O_2$ and $O_2{^-}$) and systemic resistance against of B. cinerea. Our findings shed new light on a novel strategy for biocontrol using B. laterosporus A60.

• The Plant Pathology Journal
• /
• v.31 no.2
• /
• pp.152-164
• /
• 2015

Biological control of major rice diseases has been attempted in several rice-growing countries in Asia during the last few decades and its application using antagonistic bacteria has proved to be somewhat successful for controlling various fungal diseases in field trials. Two novel endophytic Bacillus species, designated strains YC7007 and $YC7010^T$, with antimicrobial, plant growth-promoting, and systemic resistance-inducing activities were isolated from the roots of rice in paddy fields at Jinju, Korea, and their multifunctional activities were analyzed. Strain YC7007 inhibited mycelial growth of major rice fungal pathogens strongly in vitro. Bacterial blight and panicle blight caused by Xanthomonas oryzae pv. oryzae (KACC 10208) and Burkholderia glumae (KACC 44022), respectively, were also suppressed effectively by drenching a bacterial suspension ($10^7cfu/ml$) of strain YC7007 on the rhizosphere of rice. Additionally, strain YC7007 promoted the growth of rice seedlings with higher germination rates and more tillers than the untreated control. The taxonomic position of the strains was also investigated. Phylogenetic analyses based on 16S rRNA gene sequences indicated that both strains belong to the genus Bacillus, with high similarity to the closely related strains, Bacillus siamensis KACC $15859^T$ (99.67%), Bacillus methylotrophicus KACC $13105^T$ (99.65%), Bacillus amyloliquefaciens subsp. plantarum KACC $17177^T$ (99.60%), and Bacillus tequilensis KACC $15944^T$ (99.45%). The DNA-DNA relatedness value between strain $YC7010^T$ and the most closely related strain, B. siamensis KACC $15859^T$ was $50.4{\pm}3.5%$, but it was $91.5{\pm}11.0%$ between two strains YC7007 and $YC7010^T$, indicating the same species. The major fatty acids of two strains were anteiso-$C_{15:0}$ and iso $C_{15:0}$. Both strains contained MK-7 as a major respiratory quinone system. The G+C contents of the genomic DNA of two strains were 50.5 mol% and 51.2 mol%, respectively. Based on these polyphasic studies, the two strains YC7007 and $YC7010^T$ represent novel species of the genus Bacillus, for which the name Bacillus oryzicola sp. nov. is proposed. The type strain is $YC7010^T$ (= KACC $18228^T$). Taken together, our findings suggest that novel endophytic Bacillus strains can be used for the biological control of rice diseases.

• Journal of Crop Science and Biotechnology
• /
• v.11 no.2
• /
• pp.127-134
• /
• 2008

Tobamoviruses are the major viral pathogens of tomato and bell pepper. The preliminary results showed that Acibenzolar-Smethyl(ASM; S-methylbenzo(1,2,3) thiadiazole-7-carbothiate) pre-treatment to tomato and tobacco plants reduces the concentration of Tomato mosaic tobamovirus(ToMV) and Tobacco mosaic tobamovirus(TMV) in tomato and bell pepper seedlings, respectively. Pre-treatment of the indicator plant(Nicotiana glutinosa) with the ASM followed by challenge inoculation with tobamoviruses produced a reduced number and size of local lesions(67 and 79% protection over control to TMV and ToMV inoculation, respectively). In order to understand the mechanism of resistance the gene expression profiles of antiviral genes was examined. RT-PCR products showed higher expression of two viral resistance genes viz., alternative oxidase(AOX) and RNA dependent RNA polymerase(RdRp) in the upper leaves of the ASM-treated tomato plants challenge inoculation with ToMV. Further, the viral concentration was also quantified in the upper leaves by reverse transcription PCR using specific primer for movement protein of ToMV, as well as ELISA by using antisera against tobamoviruses. The results provided additional evidence that ASM pre-treatment reduced the viral movement to upper leaves. The results suggest that expressions of viral resistance genes in the host are the key component in the resistance against ToMV in the inducer-treated tomato plants.

• The Plant Pathology Journal
• /
• v.31 no.2
• /
• pp.195-201
• /
• 2015

Plant growth promoting rhizobacteria (PGPR) are known to confer disease resistance to plants. Bacillus sp. JS demonstrated antifungal activities against five fungal pathogens in in vitro assays. To verify whether the volatiles of Bacillus sp. JS confer disease resistance, tobacco leaves pre-treated with the volatiles were damaged by the fungal pathogen, Rhizoctonia solani and oomycete Phytophthora nicotianae. Pre-treated tobacco leaves had smaller lesion than the control plant leaves. In pathogenesis-related (PR) gene expression analysis, volatiles of Bacillus sp. JS caused the up-regulation of PR-2 encoding ${\beta}$-1,3-glucanase and acidic PR-3 encoding chitinase. Expression of acidic PR-4 encoding chitinase and acidic PR-9 encoding peroxidase increased gradually after exposure of the volatiles to Bacillus sp. JS. Basic PR-14 encoding lipid transfer protein was also increased. However, PR-1 genes, as markers of salicylic acid (SA) induced resistance, were not expressed. These results suggested that the volatiles of Bacillus sp. JS confer disease resistance against fungal and oomycete pathogens through PR genes expression.

• Radiation Oncology Journal
• /
• v.37 no.4
• /
• pp.302-308
• /
• 2019

The abscopal effect is a term that has been used to describe the phenomenon in which localized radiation therapy treatment of a tumor lesion triggers a spontaneous regression of metastatic lesion(s) at a non-irradiated distant site(s). Radiation therapy induced abscopal effects are believed to be mediated by activation and stimulation of the immune system. However, due to the brain's distinctive immune microenvironment, extracranial abscopal responses following cranial radiation therapy have rarely been reported. In this report, we describe the case of 42-year-old female patient with metastatic melanoma who experienced an abscopal response following her cranial radiation therapy for her brain metastasis. The patient initially presented with a stage III melanoma of the right upper skin of her back. Approximately 5 years after her diagnosis, the patient developed a large metastatic lesion in her upper right pectoral region of her chest wall and axilla. Since the patient's tumor was positive for BRAF and MEK, targeted therapy with dabrafenib and trametinib was initiated. However, the patient experienced central nervous system (CNS) symptoms of headache and disequilibrium and developed brain metastases prior to the start of targeted therapy. The patient received radiation therapy to a dose of 30 Gy delivered in 15 fractions to her brain lesions while the patient was on dabrafenib and trametinib therapy. The patient's CNS metastases improved significantly within weeks of her therapy. The patient's non-irradiated large extracranial chest mass and axilla mass also shrank substantially demonstrating the abscopal effect during her CNS radiation therapy. Following radiation therapy of her residual chest lesions, the patient was disease free clinically and her CNS lesions had regressed. However, when the radiation therapy ended and the patient continued her targeted therapy alone, recurrence outside of her previously treated fields was noted. The disease recurrence could be due to the possibility of developing BRAF resistance clones to the BRAF targeted therapy. The patient died eventually due to wide spread systemic disease recurrence despite targeted therapy.