• Korean Journal Plant Pathology
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• v.11 no.1
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• pp.9-16
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• 1995

Undiluted neoasozin solution (6.5% a.i.), an arsenic fungicide, was sprayed on 169 cankers of apple trees from early March to September in 1987 twice at intervals of one week without scraping off the affected barks. Among the treated cankers, 79.9% ceased to grow within 1∼7 weeks, 13.0% showed partial development, and 7.1% grew continuously to girdle the branches. The partially developed cankers, however, could also be cured by an additional spray after slightly piercing at the edge of cankers to facilitate the penetration of the chemical. When the canker growth was blocked, cankers were encircled by cracks developed at the marginal area of the cankers. If the cracks developed once, very few cankers grew beyond them. The above results suggest that the crack development may be the consequence of the host defense activity to wall off the pathogen. In addition to the curative efficacy, the neoasozin solution inhibited sporulation of the pathogenic fungus almost completely. However, the pathogen survived for more than three months in some cankers that externally appeared to be cured, suggesting that an indirect mode of action of the chemical against apple Valsa canker seems to be still more persuasive than the direct fungicidal effect. In the final examination conducted in the mid April of the next year, 72.7% of the cankers were completely cured by the two successive neoasozin treatments. Moreover the cure rate became 83.1% if that of partially developed cankers which were also completely cured by an additional treatment was also taken into account. Since 1989 when this method was widely applied in apple orchards in Korea, apple Valsa canker has been effectively controlled to reach a tolerable level.

• The Plant Pathology Journal
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• v.30 no.2
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• pp.125-135
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• 2014

A population model of bacterial spot caused by Xanthomonas campestris pv. vesicatoria on hot pepper was developed to predict the primary disease infection date. The model estimated the pathogen population on the surface and within the leaf of the host based on the wetness period and temperature. For successful infection, at least 5,000 cells/ml of the bacterial population were required. Also, wind and rain were necessary according to regression analyses of the monitored data. Bacterial spot on the model is initiated when the pathogen population exceeds $10^{15}cells/g$ within the leaf. The developed model was validated using 94 assessed samples from 2000 to 2007 obtained from monitored fields. Based on the validation study, the predicted initial infection dates varied based on the year rather than the location. Differences in initial infection dates between the model predictions and the monitored data in the field were minimal. For example, predicted infection dates for 7 locations were within the same month as the actual infection dates, 11 locations were within 1 month of the actual infection, and only 3 locations were more than 2 months apart from the actual infection. The predicted infection dates were mapped from 2009 to 2012; 2011 was the most severe year. Although the model was not sensitive enough to predict disease severity of less than 0.1% in the field, our model predicted bacterial spot severity of 1% or more. Therefore, this model can be applied in the field to determine when bacterial spot control is required.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3675-3681
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• 2011

Fusarium oxysporum, an important pathogen that mainly causes vascular or fusarium wilt disease which leads to economic loss. Disruption of gene encoding a heterotrimeric G-protein-${\beta}$-subunit (FGB1), led to decreased intracellular cAMP levels, reduced pathogenicity, colony morphology, and germination. The plant defense protein, Nicotiana alata defensin (NaD1) displays potent antifungal activity against a variety of agronomically important filamentous fungi. In this paper, we performed a molecular modeling and docking studies to find vital amino acids which can interact with various antifungal compounds using Discovery Studio v2.5 and GRAMMX, respectively. The docking results from FGB1-NaD1 and FGB1-antifungal complexes, revealed the vital amino acids such as His64, Trp65, Ser194, Leu195, Gln237, Phe238, Val324 and Asn326, and suggested that the anidulafungin is a the good antifungal compound.The predicted interaction can greatly assist in understanding structural insights for studying the pathogen and host-component interactions.

• The Plant Pathology Journal
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• v.39 no.5
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• pp.466-485
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• 2023

Crop productivity can be obstructed by various biotic and abiotic stresses and thus these stresses are a threat to universal food security. The information on the use of viruses providing efficacy to plants facing growth challenges owing to stress is lacking. The role of induction of pathogen-related genes by microbes is also colossal in drought-endurance acquisition. Studies put forward the importance of viruses as sustainable means for defending plants against dual stress. A fundamental part of research focuses on a positive interplay between viruses and plants. Notably, the tomato yellow leaf curl virus (TYLCV) and tomato chlorosis virus (ToCV) possess the capacity to safeguard tomato host plants against severe drought conditions. This study aims to explore the combined effects of TYLCV, ToCV, and drought stress on two tomato cultivars, Money Maker (MK, UK) and Shalala (SH, Azerbaijan). The expression of pathogen-related four cellulose synthase gene families (CesA/Csl) which have been implicated in drought and virus resistance based on gene expression analysis, was assessed using the quantitative real-time polymerase chain reaction method. The molecular tests revealed significant upregulation of Ces-A2, Csl-D3,2, and Csl-D3,1 genes in TYLCV and ToCV-infected tomato plants. CesA/Csl genes, responsible for biosynthesis within the MK and SH tomato cultivars, play a role in defending against TYLCV and ToCV. Additionally, physiological parameters such as "relative water content," "specific leaf weight," "leaf area," and "dry biomass" were measured in dual-stressed tomatoes. Using these features, it might be possible to cultivate TYLCV-resistant plants during seasons characterized by water scarcity.

• The Plant Pathology Journal
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• v.39 no.4
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• pp.409-416
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• 2023

Bacterial leaf blight of carrots caused by Xanthomonas hortorum pv. carotae (Xhc) is an important worldwide seed-borne disease. In 2012 and 2013, symptoms similar to bacterial leaf blight were found in carrot farms in Jeju Island, Korea. The phenotypic characteristics of the Korean isolation strains were similar to the type strain of Xhc. Pathogenicity showed symptoms on the 14th day after inoculation on carrot plants. Identification by genetic method was multi-position sequencing of the isolated strain JJ2001 was performed using four genes (danK, gyrB, fyuA, and rpoD). The isolated strain was confirmed to be most similar to Xhc M081. Furthermore, in order to analyze the genetic characteristics of the isolated strain, whole genome analysis was performed through the next-generation sequencing method. The draft genome size of JJ2001 is 5,443,372 bp, which contains 63.57% of G + C and has 4,547 open reading frames. Specifically, the classification of pathovar can be confirmed to be similar to that of the host lineage. Plant pathogenic factors and determinants of the majority of the secretion system are conserved in strain JJ2001. This genetic information enables detailed comparative analysis in the pathovar stage of pathogenic bacteria. Furthermore, these findings provide basic data for the distribution and diagnosis of Xanthomonas hortorum pv. carotae, a major plant pathogen that infects carrots in Korea.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2020.12a
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• pp.48-48
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• 2020

Fire blight, caused by Erwinia amylovora(Burrill), is a destructive disease of apple that damages blossoms, shoots, and woody plant organs. The fire blight disease is a worldwide problem for pome fruit growers because all popular apple cultivars are susceptible to the disease. Recently, fire blight of apple rootstocks has become a serious economic problem in high-density orchard systems in korea. The most commonly used dwarfing root stocks, M.9 and M.26, are highly susceptible to E. amylovora. The objective of the apple rootstock-breeding program has been to develop pomologically excellent rootstocks with resistance to abiotic and biotic stresses, including fire blight. Budagovsky 9 (B.9) apple rootstock is reported to be highly susceptible when inoculated with E. amylovora, although results from multiple trials showed that B.9 is resistant to rootstock blight infection in field plantings. So we tried to collect the apple rootstocks traits of fire blight resistance. The apple genotype Malus Robusta 5 (MR5) represents an ideal donor for fire blight resistance because it was described as resistant to all currently known European strains of the pathogen. The PCR for detecting the MR5 gene using the primers Md_MR5_FL_F/Md_MR5_FL_R. The results of these experiments confirmed some apple rootstocks traits of fire blight resistance showed the MR5. Furthermore, this gene is confirmed to be the resistance determinant of Mr5 as the transformed lines undergo the same gene-for-gene interaction in the host-pathogen relationship MR5-E. amylovora.

• Journal of Veterinary Science
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• v.24 no.5
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• pp.55.1-55.12
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• 2023

Background: Peste des petits ruminants (PPR), caused by the PPR virus (PPRV), is an acute and fatal contagious disease that mainly infects goats, sheep, and other artiodactyls. Peripheral blood mononuclear cells (PBMCs) are considered the primary innate immune cells. Objectives: PBMCs derived from goats were infected with PPRV and analyzed to detect the relationship between PPRV replication and apoptosis or the inflammatory response. Methods: Quantitative real-time polymerase chain reaction was used to identify PPRV replication and cytokines expression. Flow cytometry was conducted to detect apoptosis and the differentiation of CD4⁺ and CD8⁺ T cells after PPRV infection. Results: PPRV stimulated the differentiation of CD4⁺ and CD8⁺ T cells. In addition, PPRV induced apoptosis in goat PBMCs. Furthermore, apoptosis and the inflammatory response induced by PPRV could be suppressed by Z-VAD-FMK and Z-YVAD-FMK, respectively. Moreover, the virus titer of PPRV was attenuated by inhibiting caspase-1-dependent apoptosis and inflammation. Conclusions: This study showed that apoptosis and the inflammatory response play an essential role in PPR viral replication in vitro, providing a new mechanism related to the cell host response.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.134-139
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• 2010

Mycobacterium tuberculosis (Mtb) is one of the most successful pathogens to infect one third of world population. Th1-mediated immunity against Mtb infection is known as critical to express mycobacteriostatic function but it is not sufficient to resolve the infection. In this study, to verify the possibility Mtb itself change the gene expression to survive against host immune response, expression pattern of selected H37Rv genes, 16S rRNA, acr, fbpA, aceA, and ahpC, during the course of infection was measured with absolute quantitation method using real-time RT-PCR. The total number of transcripts of 16S rRNA increased during the course of infection, which was coincide with the increasing CFU. The total number of fbpA transcripts per CFU, which encode typical secreted Mtb antigen, Ag85A, increased for 10 days of infection before decreasing. The number of transcripts of acr per CFU, which encode heat shock protein, ${\alpha}$-crystallin, increased during the infection, and ahpC and aceA, they both are enzymes produced in oxidative stressful condition, increased for 20 days and then slightly decreased on day 30. These findings are one of survival strategy of pathogen evading host immune response lead to persistent infection inside host cells.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.61-61
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• 2015

Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most destructive diseases of rice worldwide. The rice - M. oryzae pathosystem has become a model in the study of plant - fungal interactions due to its economic importance and accumulating knowledge. During the evolutionary arms race with M. oryzae, rice plants evolved a repertoire of Resistance (R) genes to protect themselves from diseases in a gene-for-gene fashion. M. oryzae secretes a battery of small effector proteins to manipulate host functions for its successful infection, and some of them are recognized by host R proteins as avirulence effectors (AVR), which turns on strong immunity. Therefore, the analysis of interactions between AVRs and their cognate R proteins provide crucial insights into the molecular basis of plant - fungal interactions. Rice blast resistance genes Pik, Pia, Pii comprise pairs of protein-coding ORFs, Pik-1 and Pik-2, RGA4 and RGA5, Pii-1 and Pii-2, respectively. In all three cases, the paired genes are tightly linked and oriented to the opposite directions. In the AVR-Pik/Pik interaction, it has been unraveled that AVR-Pik binds to the N-terminal coiled-coil domain of Pik-1. RGA4 and RGA5 are necessary and sufficient to mediate Pia resistance and recognize the M. oryzae effectors AVR-Pia and AVR1-CO39. A domain at the C-terminus of RGA5 characterized by a heavy metal associated domain was identified as the AVR-binding domain of RGA5. Similarly, physical interactions among Pii-1, Pii-2 and AVR-Pii are being analyzed.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.10
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• pp.1496-1511
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• 2015

The study aimed to compare the necrotic enteritis (NE)-induced transcriptome differences between the spleens of Marek's disease resistant chicken line 6.3 and susceptible line 7.2 co-infected with Eimeria maxima/Clostridium perfringens using RNA-Seq. Total RNA from the spleens of two chicken lines were used to make libraries, generating 42,736,296 and 42,617,720 usable reads, which were assembled into groups of 29,897 and 29,833 mRNA genes, respectively. The transcriptome changes were investigated using the differentially expressed genes (DEGs) package, which indicated 3,255, 2,468 and 2,234 DEGs of line 6.3, line 7.2, and comparison between two lines, respectively (fold change ${\geq}2$, p<0.01). The transcription levels of 14 genes identified were further examined using qRT-PCR. The results of qRT-PCR were consistent with the RNA-seq data. All of the DEGs were analysed using gene ontology terms, the Kyoto Encyclopedia of Genes and Genomes (KEGG) database and the DEGs in each term were found to be more highly expressed in line 6.3 than in line 7.2. RNA-seq analysis indicated 139 immune related genes, 44 CD molecular genes and 150 cytokines genes which were differentially expressed among chicken lines 6.3 and 7.2 (fold change ${\geq}2$, p<0.01). Novel mRNA analysis indicated 15,518 novel genes, for which the expression was shown to be higher in line 6.3 than in line 7.2 including some immune-related targets. These findings will help to understand host-pathogen interaction in the spleen and elucidate the mechanism of host genetic control of NE, and provide basis for future studies that can lead to the development of marker-based selection of highly disease-resistant chickens.