• The Plant Pathology Journal
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• v.37 no.2
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• pp.124-136
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• 2021

Bark canker, wood discoloration, and wilting of the duku tree (Lansium domesticum) along the watershed of Komering River, South Sumatra Province, Indonesia first appeared in 2013. The incidence of tree mortality was 100% within 3 years in badly infected orchards. A Ceratocystis species was consistently isolated from the diseased tissue and identified by morphological and sequence analyses of the internal transcribed spacer (ITS) and β-tubulin regions. Pathogenicity tests were conducted and Koch's postulates were confirmed. The fungus was also pathogenic on Acacia mangium, but was less pathogenic on mango. Partial flooding was unfavourable for disease development. Two described isolates (WRC and WBC) had minor variation in morphology and DNA sequences, but the former exhibited a more pathogenic on both duku and acacia. The ITS phylogenies grouped the most pathogenic isolate (WRC) causing wilting of the duku tree within the aggressive and widely distributed ITS5 haplotype of C. fimbriata.

• The Plant Pathology Journal
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• v.37 no.4
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• pp.404-412
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• 2021

Despite the plant microbiota plays an important role in plant health, little is known about the potential interactions of the flower microbiota with pathogens. In this study, we investigated the microbial community of apple blossoms when infected with Erwinia amylovora. The long-read sequencing technology, which significantly increased the genome sequence resolution, thus enabling the characterization of fire blight-induced changes in the flower microbial community. Each sample showed a unique microbial community at the species level. Pantoea agglomerans and P. allii were the most predominant bacteria in healthy flowers, whereas E. amylovora comprised more than 90% of the microbial population in diseased flowers. Furthermore, gene function analysis revealed that glucose and xylose metabolism were enriched in diseased flowers. Overall, our results showed that the microbiome of apple blossoms is rich in specific bacteria, and the nutritional composition of flowers is important for the incidence and spread of bacterial disease.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.1041-1050
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• 2009

Equine respiratory disease is a common cause of poor performance and training interruptions. The higher incidence rate of infectious upper respiratory disease (IURD) in thoroughbred racehorses at the Seoul Race Park coincided with the frequent stabling season, shorter stabling periods, and younger ages in this study. Incidence rates were also correlated with significantly lower proportions of cells expressing MHC class II-, CD2 antigen-, $CD4^+$- or $CD8^+$-T lymphocyte-, and B lymphocyte in IURD patients compared with healthy control groups in the summer and fall and in 2-and-3-year-old groups. The data suggested that movement and new environments may have resulted in immunosuppression and inappropriate responses to respiratory pathogens in IURD patients. The IURD incidence decreased with age, perhaps by the acquisition of immunity, and study results suggested that immunologic protection was associated with IURD, particularly in young thoroughbred racehorses. Streptococci isolates were identified in 11 of 72 IURD horses, and 3 of these isolates were identified as Streptococcus. equi subsp. equi. S. equi subsp. zooepidemicus was isolated from 2 of 23 IURD horses in the spring (8.7%), 5 of 23 in the summer (21.7%), and 1 of 6 in winter (16.7%). S. equi subsp. zooepidemicus (5%) was also identified in 3 of 61 isolates from clinically normal horses. Racetracks should implement anti-IURD protective measures by assessing the capacity of equine immunologic protection at the Park and by limiting the introduction of specific respiratory pathogens (such as S. equi subsp. equi) by preventing the access of infected but subclinical horses with a specified respiratory pathogen-free certification system prior to Park entry.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.386-396
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• 2013

Reactive oxygen species (ROS) generation in tomato plants by Ralstonia solanacearum infection and the role of hydrogen peroxide ($H_2O_2$) and nitric oxide in tomato bacterial wilt control were demonstrated. During disease development of tomato bacterial wilt, accumulation of superoxide anion ($O_2{^-}$) and $H_2O_2$ was observed and lipid peroxidation also occurred in the tomato leaf tissues. High doses of $H_2O_2$ and sodium nitroprusside (SNP) nitric oxide donor showed phytotoxicity to detached tomato leaves 1 day after petiole feeding showing reduced fresh weight. Both $H_2O_2$ and SNP have in vitro antibacterial activities against R. solanacearum in a dose-dependent manner, as well as plant protection in detached tomato leaves against bacterial wilt by $10^6$ and $10^7$ cfu/ml of R. solanacearum. $H_2O_2$- and SNP-mediated protection was also evaluated in pots using soil-drench treatment with the bacterial inoculation, and relative 'area under the disease progressive curve (AUDPC)' was calculated to compare disease protection by $H_2O_2$ and/or SNP with untreated control. Neither $H_2O_2$ nor SNP protect the tomato seedlings from the bacterial wilt, but $H_2O_2$ + SNP mixture significantly decreased disease severity with reduced relative AUDPC. These results suggest that $H_2O_2$ and SNP could be used together to control bacterial wilt in tomato plants as bactericidal agents.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.493-500
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• 2012

In order to confirm the possibility of UV utilization as a means for disease protection in grapevine the stilbene contents and the disease incidence in UV irradiated leaves were investigated. UV irradiation significantly increased the contents of resveratrol, piceatannol and piceid, in them, resveratrol and piceid showed in vitro inhibition of spore germination and mycelium growth of Botrytis cinerea. The accumulation of both the stilbenes in UV irradiated leaves seems to be enough to inhibit the B. cinerea growth, since the formation of necrotic spot on the leaves was considerably inhibited when they were inoculated with the conidial spores of B. cinerea. However the stilbenes were accumulated only in the leaves exposed directly to UV showing a limited translocation ability of the compounds. Thus it would be necessary to develop a method to evenly irradiate the entire crown of plant with UV in order to expect to protect them from disease by UV irradiation.

• The Plant Pathology Journal
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• v.37 no.2
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• pp.194-199
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• 2021

Blackleg is a serious disease in Brassica plants, causing moderate to severe yield losses in rapeseed worldwide. Although China has not suffered from this disease yet (more aggressive Leptosphaeria maculans is not present yet), it is crucial to take provisions in breeding for disease resistance to have excellent blackleg-resistant cultivars already in the fields or in the breeding pipeline. The most efficient strategy for controlling this disease is breeding plants with identified resistance genes. We selected 135 rapeseed accessions in Sichuan, including 30 parental materials and 105 hybrids, and we determined their glucosinolate and erucic acid content and confirmed 17 double-low materials. A recently developed single-nucleotide polymorphism (SNP) marker, SNP_208, was used to genotype allelic Rlm1/rlm1 on chromosome A07, and 87 AvrLm1-resistant materials. Combined with the above-mentioned seed quality data, we identified 11 AvrLm1-resistant double-low rapeseed accessions, including nine parental materials and two hybrids. This study lays the foundation of specific R gene-oriented breeding, in the case that the aggressive Leptosphaeria maculans invades and establishes in China in the future and a robust and less labor consuming method to identify resistance in canola germplasm.

• Journal of Veterinary Science
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• v.23 no.4
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• pp.25.1-25.14
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• 2022

Background: The commercially available Newcastle disease (ND) vaccines were developed based on Newcastle disease virus (NDV) isolates genetically divergent from field strains that can only prevent clinical disease, not shedding of virulent heterologous virus, highlighting the need to develop genotype-matched vaccines Objectives: This study examined the efficacy of the NDV genotype-matched vaccine, mIBS025 strain formulated in standard vaccine stabilizer, and in carboxymethyl sago starch-acid hydrogel (CMSS-AH) following vaccination via an eye drop (ED) and drinking water (DW). Methods: A challenge virus was prepared from a recent NDV isolated from ND vaccinated flock. Groups of specific-pathogen-free chickens were vaccinated with mIBS025 vaccine strain prepared in a standard vaccine stabilizer and CMSS-AH via ED and DW and then challenged with the UPM/NDV/IBS362/2016 strain. Results: Chickens vaccinated with CMSS-AH mIBS025 ED (group 2) developed the earliest and highest Hemagglutination Inhibition (HI) NDV antibody titer (8log₂) followed by standard mIBS025 ED (group 3) (7log₂) both conferred complete protection and drastically reduced virus shedding. By contrast, chickens vaccinated with standard mIBS025 DW (group 5) and CMSS-AH mIBS025 DW (group 4) developed low HI NDV antibody titers of 4log₂ and 3log₂, respectively, which correspondingly conferred only 50% and 60% protection and continuously shed the virulent virus via the oropharyngeal and cloacal routes until the end of the study at 14 dpc. Conclusions: The efficacy of mIBS025 vaccines prepared in a standard vaccine stabilizer or CMSS-AH was affected by the vaccination routes. The groups vaccinated via ED had better protective immunity than those vaccinated via DW.

• Korean Journal of Agricultural Science
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• v.50 no.2
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• pp.241-247
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• 2023

Erwinia amylovora , which causes fire blight disease on apple and pear trees, is one of the most important phytopathogens because of its devastating impact. Currently, the only way to effectively control fire blight disease is through the use of antibiotics such as streptomycin, kasugamycin, or oxytetracycline. However, problems with the occurrence of resistant strains due to the overuse of antibiotics are constantly being raised. It is therefore necessary to develop novel disease control methods through an advanced understanding of the pathogenesis mechanism of E. amylovora . To better understand the pathogenesis of E. amylovora , we investigated unknown virulence factors by random mutagenesis and screening. Random mutants were generated by Tn5 transposon insertion, and the pathogenicity of the mutants was assessed by inoculation of the mutants on apple fruitlets. A total of 17 avirulent mutants were found through screening of 960 random mutants. Among them, 14 mutants were already reported as non-pathogenic strains, while three mutants, TS3128_M2899 (ΔSUFU ), TS3128_M2939 (ΔwcaG ), and TS3128_M3747 (ΔrecB ), were not reported. Further study of the association between E. amylovora pathogenicity and these 3 novel genes may provide new insight into the development of control methods for fire blight disease.

• Korean Journal of Agricultural Science
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• v.50 no.4
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• pp.723-734
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• 2023

Erwinia pyrifoliae, which causes black shoot blight in apple and pear trees, was first identified in Korea in 1995. Extensive measures are typically used to control the disease by eradicating trees in diagnosed orchards, owing to the detrimental impact of the disease on apple and pear production. However, despite governmental efforts, the disease has continuously spread. In this study, we analyzed the current status of the black shoot blight occurrence in apple and pear orchards between 1995 to 2022. Our findings reveal that over the past 28 years, black shoot blight has occurred in 26 cities and districts across five Korean provinces. The affected regions are predominantly concentrated in the northern part of Korea, including the Gangwon and Gyeonggi provinces. Furthermore, black shoot blight has gradually expanded to the northern provincial regions of Chungbuk, Chungnam, and Gyeongbuk, which are centrally situated in Korea. Furthermore, the occurrence pattern of black shoot blight differed between apple and pear orchards; in apple orchards, black shoot blight occurred consistently each year, with a sudden increase in cases in 2020; however, in pear orchards, it has considerably decreased since 2007. To the best of our knowledge, this is the first comprehensive report on the occurrence of black shoot blight in apple and pear trees in 28 years, and the results will provide valuable insights for future disease management strategies.

• Journal of Chest Surgery
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• v.17 no.3
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• pp.346-355
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• 1984

77 cases of Aortic Valve Replacement, which were composed of 64 rheumatic valvular heart disease and 13 combined congenital heart disease, were operated at Seoul National University Hospital for Aortic valvular disease during the period from June 1968 to December 1983. Among these 64 rheumatic aortic valvular heart disease cases, 8 patients were expired during and immediate after operation and overall mortality rate was 12.5%. For more precise remarks, these patients were divided into two periodic groups, 1st period [from 1968 to 1976] and 2nd [from 1977 to 1983] when annual open heart surgery were over 100 cases, and in 1st period three of four patients were died and in 2nd period five of sixty patients were died and its mortality rate was 8.3%. There were 12 cases of postoperative complication, which were 3 cases of remaining other valvular heart disease required MVR, 2 paravalvular leaks [one of them got Redo AVR], 4 thromboembolism or problem of anticoagulant therapy, 2 late death due to SBE with replaced valve failure and one functional AS with small sized valve. Operative death was affected by pump-time and aortic cross-clamping time, heart size, Ejection Fraction, LVEDP and symptom duration, and other many factors may influence the survival rate. Improved operative technique and myocardial protection and meticulous evaluation of the preoperative patient status will make the AVR safer.