Different Regions Of South Korea Research Articles

Viral Metatranscriptomic Analysis to Reveal the Diversity of Viruses Infecting Satsuma Mandarin (Citrus unshiu) in Korea.

Citrus cultivation plays a pivotal role, making a significant contribution to global fruit production and dietary consumption. Accurate identification of viral pathogens is imperative for the effective management of plant viral disease in citrus crops. High-throughput sequencing serves as an alternative approach, enabling comprehensive pathogen identification on a large scale without requiring pre-existing information. In this study, we employed HTS to investigate viral pathogens infecting citrus in three different regions of South Korea: Jejudo (Jeju), Wando-gun (Wando), and Dangjin-si (Dangjin). The results unveiled diverse viruses and viroids that exhibited regional variations. Notably, alongside the identification of well-known citrus viruses such as satsuma dwarf virus, citrus tatter leaf virus, and citrus leaf blotch virus (CLBV), this study also uncovered several viruses and viroids previously unreported in Korean citrus. Phylogenetic analysis revealed that majority of identified viruses exhibited the closest affilations with isolates from China or Japan. However, CLBV and citrus viroid-I-LSS displayed diverse phylogenetic positions, reflecting their regional origins. This study advances our understanding of citrus virome diversity and regional dynamics through HTS, emphasizing its potential in unraveling intricate viral pathogens in agriculture. Consequently, it significantly contributes to disease management strategies, ensuring the resilience of the citrus industry.

First report of Kalanchoe Latent Virus naturally infecting common bean (Phaseolus vulgaris L.) in South Korea.

The common bean (Phaseolus vulgaris; family: Fabaceae) is an economically and nutritionally important food crop worldwide (Ganesan et al. 2017). In 2021, several plants collected from different provinces in South Korea had symptoms of viral infections (e.g., mild yellow-greenish speckling, stunting, crinkling, and deformed leaves). To identify the causal pathogens, total RNA was isolated from pooled leaf tissues from all samples (n = 29) for paired-end high-throughput sequencing (HTS). The cDNA library was constructed after eliminating ribosomal RNA using the TruSeq RNA Sample Prep Kit and then sequenced using the Illumina NovaSeq 6000 platform (Macrogen, Korea). The 297,868,156 paired-end clean reads (150 nt) were de novo assembled using Trinity with default parameters. BLASTx was used for the contig analysis, which revealed the pooled samples were infected with several plant viruses (e.g., turnip mosaic virus, zucchini yellow mosaic virus, cucumber mosaic virus, lily mottle virus). Notably, the assembled contigs included a single viral contig (8,472 nt) comprising the nearly complete KLV genome (HTS mean coverage: 39.46%). Kalanchoe latent virus (KLV; genus: Carlavirus; family: Betaflexiviridae) has been detected in Kalanchoë blossfeldiana (Hearon 1982), Chenopodium quinoa (Dinesen et al. 2009), and Graptopetalum paraguayense (Sorrentino et al. 2017). The sequence was most similar (96.28% nucleotide identity; 99% query coverage) to KLV isolate DSMZ PV-0290 (GenBank: OP525283) from Denmark. The contig sequence was validated via reverse transcription-polymerase chain reaction (RT-PCR) using total RNA extracted from the 29 individually stored samples and nine primer sets specific for the KLV contig. All nine contig-specific overlapping fragments were amplified from only a P. vulgaris plant with mild yellowing mosaic symptoms collected on July 6, 2021, in Jeongseon County, South Korea. Additionally, 5' and 3' rapid amplification of cDNA ends (RACE)-specific primers were designed for the KLV contig sequence to determine the terminal ends of the genome of the South Korean KLV isolate using the 5'/3' RACE System (Invitrogen, Carlsbad, CA, USA). All of the amplified and overlapping fragments were cloned into the RBC T&A Cloning Vector (RBC Bioscience, Taipei, Taiwan) and sequenced using the Sanger method. The obtained full-length genomic sequence of the KLV isolate (KLV-SK22) was 8,517 nt long and was deposited in GenBank OQ718816. According to the BLASTn analysis, KLV-SK22 was highly similar (96.30% sequence identity; 100% query coverage) to the DSMZ PV-0290 isolate. Phylogenetic trees constructed on the basis of coat protein and RNA-dependent RNA polymerase amino acid sequences revealed that KLV-SK22 is closely related to the DSMZ PV-0290 and PV-0290B isolates from Denmark, respectively. At the genome and gene levels, the individual sequence identities between the carlaviruses and other KLV isolates were 96.29% to 100% (Adams et al. 2004). Additionally, an RT-PCR analysis using detection primers specific for KLV-SK22 did not detect KLV in 15 samples (P. vulgaris = 3, Glycine max = 8, Pueraria montana = 2, Trifolium repens = 1, and Vigna angularis = 1) randomly collected from different regions in South Korea. Based on these results, KLV infection may not be widespread at this time in South Korea. To the best of our knowledge, this is the first report of KLV in P. vulgaris in South Korea or elsewhere. Our findings will aid future research on the epidemiology and long-term management of KLV-related diseases.

Characteristics of heavy metals in road dust: An overview of South Korean cases

The urbanization and industrialization of our society necessitate the extension of road traffic systems. Road dust generated by road traffic is harmful to the human respiratory system. In particular, heavy metals adsorbed on road dust can pose substantial risks to human health owing to their toxicity, environmental longevity, and ability to accumulate in the human body. Although the evaluation of the concentration of heavy metals in road dust is essential for understanding their sources and risks to human health, there is a lack of comprehensive information on the heavy metal content in road dust in South Korea. In this review, sampling methods and analytical techniques for characterizing the contents of various heavy metals in road dust collected from different regions of South Korea are discussed. Cu, Zn, Cd, Pb, Ni, Cr, As, and Hg are the most frequently found heavy metals in road dust, and their concentrations are strongly associated with the sampling locations (e.g., industrial vs. residential sites and rural vs. urban areas) and particle size of the road dust. Road dust samples collected from more industrialized regions tend to contain more heavy metals. Further, smaller dust particles are likely apt to contain more heavy metals. The application of non-destructive analytical techniques is also necessary for the accurate characterization of heavy metals in road dust.

Regional Differences in Willingness to Pay for Mitigation of Air Pollution from Coal-Fired Power Plants in South Korea

This study examined whether people who reside in different regions of South Korea exhibit different WTP for the mitigation of PM2.5 emissions from coal-fired power plants by restricting their operation during the winter and spring when air pollution becomes severe. The eastern portions of the country are relatively insulated from the harmful effects of PM2.5 emissions due to northwest winds which cause air pollutants generated from coal-fired power plants to be carried out to the East Sea (Sea of Japan). Consequently, our sample group was divided into central, western, eastern, and southern regions, and a contingent valuation method, combined with a double-bounded dichotomous choice, was used to derive people’s WTP for the mitigation of PM2.5 emissions. Our estimation results indicated that respondents who live in eastern regions showed a significantly lower WTP (about KRW 1280/month) than the mean WTP of other regions (above KRW 1337/month). Thus, we suggest that the current Seasonal Management System of PM2.5 emissions should be modified to consider regional differences. Statistical results from this study reinforce our suggestions—almost 78 percent of survey respondents support a revision of the current SMS policy and are in favor of a revised SMS policy—one that exempts eastern regions from a nationwide shutdown of coal-fired generation from December to March. Exempting coal-fired power plants in eastern regions from the Seasonal Management System might result in significant fiscal savings without a corresponding increase in nationwide PM2.5 concentrations.

Physicochemical characteristics and seasonal variations of PM2.5 in urban, industrial, and suburban areas in South Korea

Among countries that are a part of the Organization for Economic Co-operation and Development, South Korea is the most exposed to PM2.5. Despite the country having implemented various strategies to limit PM2.5 emissions, its concentrations are still high enough to pose serious environmental and health concerns. Herein, we monitored various physiochemical properties of PM2.5 across different regions in South Korea from January 1 to December 31, 2021. Specifically, the study area consisted of the city center, industrial complexes, and suburban areas. Before analyzing dynamics of emissions specific to each site, the Clean Air Policy Support System data for the three areas were compared to elucidate their respective primary emission sources. The particle concentrations for the three areas were 21.8–26.44 µg/m3, with the highest concentrations being observed in March. All the three areas exhibited high ratios of NO3− across all seasons. The particle number concentrations in the three sites were 1.3–1.5 × 107, and the peak points of the concentrations were different in every site: city center (40 nm), industrial complexes (60 nm), and suburban areas (80 nm). We also conducted potential source contribution function and conditional bivariate probability function analyses. These analyses were conducted to determine the inflow direction of the pollution sources for high PM2.5 episodes. For the episodes that occurred in spring and winter, there were no differences in the PM2.5 concentrations between the three sites. Overall, the insights gained from this study offer a framework for developing air-quality management policies in South Korea, specifically in the context of PM2.5 emissions.

Non-Gaussian multivariate statistical monitoring of spatio-temporal wind speed frequencies to improve wind power quality in South Korea.

The spatial and temporal variability of renewable energy resources, particularly wind energy, should be statistically evaluated to achieve sustainable economic development to mitigate climate change. In this study, a non-Gaussian multivariate statistical monitoring approach is proposed to investigate the wind speed frequencies across different regions of South Korea. Anemometer data were first collected in 11 different provinces of South Korea with hourly resolution for one year. The best-of-fit for the corresponding distribution function was identified to characterize the behavior of the wind speed frequency at each region among more than 60 candidate functions using the chi-squared test. Furthermore, a non-Gaussian multivariate statistical monitoring method based on the Hotelling T2 chart was developed to spatially and temporally analyze the physical patterns of the wind speed frequencies using the estimated distribution parameters. Then determination rule of cut-in and cut-out speeds of wind turbine was suggested to improve the wind power quality across the regions. The results indicated that Weibull and Gamma distributions are best-of-fit functions of each province in South Korea; the physical patterns of wind including the average wind speed and gale can be identified by distribution parameters. Furthermore, the proposed non-Gaussian multivariate monitoring approach can elucidate the spatial and temporal variability of the regional wind speed frequencies, including the average wind speeds and extreme wind events across South Korea. Based on the statistically identified variability of wind behavior, the wind power quality of wind turbines can be improved by 12% on average by adjusting the cut-in and cut-off speed. Thus, the proposed non-Gaussian multivariate monitoring approach can provide practical guidelines for manufacturers to achieve reliable wind energy generation by considering the spatial and temporal wind behavior.

Multi-Year Spatial Variability of the Impact of Sociodemographic, Behavioural, and Health Factors on Depression of Older Adults

Abstract. The mental health of older adults has become a critical issue with the rising suicide rate in older adults in South Korea. Various factors related to depression can make heterogeneous impacts in different regions. Yet, such spatial perspectives have been rarely integrated with the mental health studies in South Korea. This study aims to explore 1) how differently each factor of sociodemographic characteristics, social interactions, and health-related behaviors is associated with depression of older adults throughout different regions in South Korea, and 2) how those relationships change across five survey years (2008–2016) for a long term. Spatially local regression and small-multiple map visualization were applied to analyze a longitudinal panel survey dataset named KLoSA, collected in South Korea. It is found that age, marital status, in-person social contact frequency, and perceived physical health are significantly correlated with depression in more regions than other variables. The local regression coefficients and significance vary by region and year.

Bacterial Community and Diversity from the Watermelon Cultivated Soils through Next Generation Sequencing Approach.

Knowledge and better understanding of functions of the microbial community are pivotal for crop management. This study was conducted to study bacterial structures including Acidovorax species community structures and diversity from the watermelon cultivated soils in different regions of South Korea. In this study, soil samples were collected from watermelon cultivation areas from various places of South Korea and microbiome analysis was performed to analyze bacterial communities including Acidovorax species community. Next generation sequencing (NGS) was performed by extracting genomic DNA from 92 soil samples from 8 different provinces using a fast genomic DNA extraction kit. NGS data analysis results revealed that, total, 39,367 operational taxonomic unit (OTU), were obtained. NGS data results revealed that, most dominant phylum in all the soil samples was Proteobacteria (37.3%). In addition, most abundant genus was Acidobacterium (1.8%) in all the samples. In order to analyze species diversity among the collected soil samples, OTUs, community diversity, and Shannon index were measured. Shannon (9.297) and inverse Simpson (0.996) were found to have the highest diversity scores in the greenhouse soil sample of Gyeonggi-do province (GG4). Results from NGS sequencing suggest that, most of the soil samples consists of similar trend of bacterial community and diversity. Environmental factors play a key role in shaping the bacterial community and diversity. In order to address this statement, further correlation analysis between soil physical and chemical parameters with dominant bacterial community will be carried out to observe their interactions.

Nitrous oxide emission and sweet potato yield in upland soil: Effects of different type and application rate of composted animal manures.

The aims of this study were to determine type and application rate of composted animal manure to optimize sweet potato yield relative to N2O emissions from upland soils. To this end, the study was conducted on upland soils amended with different types and rates of composted animal manure and located at two geographically different regions of South Korea. Field trials were established at Miryang and Yesan in South Korea during the sweet potato (Ipomoea batatas) growing season over 2 years: 2017 (Year 1) and 2018 (Year 2). Three composted animal manures (chicken, cow, and pig) were applied at the rates of 0, 10, and 20Mgha-1 to upland soils in both locations. In both Years and locations, manure type did not affected significantly cumulative N2O emissions from soil during the sweet potato growing season or the belowground biomass of sweet potato. However, application rate of animal manures affected significantly the cumulative N2O emission, nitrogen (N) in soil, and belowground biomass of sweet potato. An increase in cumulative N2O emission with application rates of animal manures was related to total N and inorganic N concentration in soil. The belowground biomass yield of sweet potato but also the cumulative N2O emission increased with increasing application rate of composted animal manures up to 7.6 and 16.0Mgha-1 in Miryang and Yesan, respectively. To reduce N2O emission from arable soil while increasing crop yield, composted animal manures should be applied at less than application rate that produce the maximum belowground biomass of sweet potato.

Impact of Antibiotic Prescribing Patterns on Susceptibilities of Uropathogens in Children below 24 Months Old.

Monitoring regional antibiotic resistance patterns of uropathogens are important for deciding suitable empirical antibiotics for urinary tract infections (UTIs) in children. This study aimed to investigate regional differences in antimicrobial susceptibility patterns of E. coli and Klebsiella spp. in children below 24 months old, diagnosed with their first episode of UTI, and to find factors associated with an increased risk for UTI caused by extended-spectrum β-lactamase (ESBL)-producing uropathogens. This was a retrospective cohort study of children diagnosed between 2011 and 2017 in four different hospitals located in four different regions of South Korea; regions A, B, C, and D. The government’s big data repository was used to acquire data on regional antibiotic prescriptions. The pooled antimicrobial susceptibilities of E. coli and Klebsiella spp. (n = 2044) were as follows: ampicillin–sulbactam (61.0%), 3rd generation cephalosporin (3C) (82.8%), and trimethoprim–sulfamethoxazole (72.0%). Multivariate analysis showed that children diagnosed at hospital A (OR, 1.8; 95% confidence interval [CI], 1.2–2.6; P = 0.002) and every year that increased in the study period (OR, 1.1; 95% CI, 1.1–1.2; P < 0.001) were factors associated with an increased risk for UTIs with ESBL-producers. Regions A and B had significantly higher amounts of oral 3Cs prescribed compared to regions C and D (P = 0.009), which correlate with hospitals in the regions that had higher proportions of UTIs with ESBL-producing uropathogens (A and B vs. C and D, P < 0.001). Therefore, children in certain regions are at a higher risk for UTIs caused by ESBL-producers compared to other regions, which correlate with regions that had higher amounts of oral 3Cs prescribed.

Validation of an optimized HPLC/UV method for the quantification of flavonoids in lotus

Flavonoids present in the leaves of lotus (Nelumbo nucifera) grown in different regions of South Korea (Yeongcheon, Haenam, and Seocheon) and at different harvest times (July to September) were determined. Flavonoid contents in lotus extracts were identified and analyzed using high-performance liquid chromatography (HPLC). The HPLC results revealed that the flavonoid contents of the lotus extracts varied at different harvesting times, with the highest content in July. Analysis of the flavonoid content in the leaves from the different regions showed the highest contents of isorhamnetin-3-O-glucoside, quercetin 3-O-glucuronide, and quercetin 3-O-glucoside in Yeongcheon, Korea, and highest contnts of rutin, myricetin, kaempferol 3-O-glucoside, and quercetin in Haenam, Korea. The HPLC method was validated and optimized to quantify quercetin 3-O-glucuronide; it showed good linearity (1000–62.5 µg/mL, r2 = 0.9999), accuracy (106%–108%), and precision (RSD ≤ 1.70%). Determination of flavonoid content in lotus is valuable for producing medicinal crops and identifying the optimal sources to increase the quantity of clinically available medicines.

The botanical origin and antioxidant, anti-BACE1 and antiproliferative properties of bee pollen from different regions of South Korea

BackgroundBee pollen (BP) has been used as a traditional medicine and food diet additive due to its nutritional and biological properties. The potential biological properties of bee pollen vary greatly with the botanical and geographical origin of the pollen grains. This study was conducted to characterize the botanical origin and assess the antioxidant effects of ethanol extracts of 18 different bee pollen (EBP) samples from 16 locations in South Korea and their inhibitory activities on human β-amyloid precursor cleavage enzyme (BACE1), acetylcholinesterase (AChE), human intestinal bacteria, and 5 cancer cell lines.MethodsThe botanical origin and classification of each BP sample was evaluated using palynological analysis by observing microscope slides. We measured the biological properties, including antioxidant capacity, inhibitory activities against human BACE1, and AChE, and antiproliferative activities toward five cancer cell lines, of the 18 EBPs. In addition, the growth inhibitory activities on four harmful intestinal bacteria, six lactic acid-producing bacteria, two nonpathogenic bacteria, and an acidulating bacterium were also assessed.ResultsFour samples (BP3, BP4, BP13 and BP15) were found to be monofloral and presented four dominant pollen types: Quercus palustris, Actinidia arguta, Robinia pseudoacacia, and Amygdalus persica. One sample (BP12) was found to be bifloral, and the remaining samples were considered to be heterofloral. Sixteen samples showed potent antioxidant activities with EC50 from 292.0 to 673.9 μg mL− 1. Fourteen samples presented potent inhibitory activity against human BACE1 with EC50 from 236.0 to 881.1 μg mL− 1. All samples showed antiproliferative activity toward the cancer cell lines PC-3, MCF-7, A549, NCI-H727 and AGS with IC50 from 2.7 to 14.4 mg mL− 1, 0.9 to 12.7 mg mL− 1, 5.0 to > 25 mg mL− 1, 2.7 to 17.7 mg mL− 1, and 2.4 to 8.7 mg mL− 1, respectively. In addition, total phenol and flavonoid contents had no direct correlation with antioxidant, anti-human BACE1, or antiproliferative activities.ConclusionFundamentally, Korean bee pollen-derived preparations could be considered a nutritional addition to food to prevent various diseases related to free radicals, neurodegenerative problems, and cancers. The botanical and geographical origins of pollen grains could help to establish quality control standards for bee pollen consumption and industrial production.

Marriage as a social tie in the relation of depressive symptoms attributable to air pollution exposure among the elderly

BackgroundAir pollution is a risk factor for depression or depressive symptoms. However, few studies have examined an effect modifier as a protective factor against depressive symptoms associated with air pollution, including social support. Notably, less is known about a married relationship in the association between exposure to air pollution and depressive symptoms among the elderly. MethodsThis study included 2122 marrieds and 607 non-marrieds, recruited in 2014–2017 from different regions of South Korea. Depressive symptoms were measured by the Korean version of the Geriatric Depression Scale Short Form (SGDS-K). After adjustment for potential confounders using propensity score of being assigned to the marrieds, we examined the extent of whether the effects of exposure to air pollutants (PM10, PM2.5, and NO2) on depressive symptoms were different between marrieds and non-marrieds. Subgroup analyses by gender and residence area were also performed. ResultsMarrieds than non-marrieds were less likely to have depressive symptoms and had smaller SGDS-K associated with increased exposure to PM10 and PM2.5 concentrations, respectively. After stratification of subjects by gender and residence area, the interaction term appeared to be significant among men and the non-metropolitan group, indicating the protective effect of married relationships on depressive symptoms attributable to air pollution exposure in them. LimitationsAlthough we adjusted the propensity score, our findings might be confounded by the contextual effect associated with married relationships. ConclusionsA married relationship, as a social tie, may attenuate the effect of exposure to air pollution on depressive symptoms among the elderly. Nonetheless, additional research is worthwhile to explore the extent of other social relationships in the association between air pollution exposure and depressive symptoms.

Changes of Atmospheric and Blood Concentrations of Lead and Cadmium in the General Population of South Korea from 2008 to 2017.

We measured changes in atmospheric and blood levels of lead and cadmium in the South Korean general population during the past decade. Blood data of 16,873 adults were taken from the Korean National Health and Nutrition Examination Survey (KNHANES, 2008–2017). Atmospheric data were taken from 66 air quality monitoring sites in 16 different regions in South Korea. From 2008 to 2017, the geometric mean (GM) blood lead level decreased from 2.37 to 1.46 μg/dL (38.4% decrease), and the atmospheric lead concentration decreased by 61.0% in the overall population. During this time, the GM blood cadmium level decreased from 0.88 to 0.72 μg/L (18.2% decrease), and the atmospheric cadmium concentration decreased by 63.6%. Multiple linear regression analysis indicated that a half reduction in air lead was associated with a 0.09 μg/dL decrease in blood lead (95% CI: 0.03 to 0.15) in a subgroup of the metropolitan city population. However, a half reduction in air cadmium had no significant effect on blood cadmium. Multiple linear regression analyses indicated that the decrease in blood lead level over 10 years in Korea was related to the decrease in atmospheric lead concentration. However, the decrease in blood cadmium level during this time was not significantly associated with the decrease in atmospheric cadmium concentration. Our findings suggest that inhalation is a major source of lead exposure, but not of cadmium exposure. Ingestion of dietary cadmium presumably has a stronger impact on blood cadmium levels.

Content Analysis of Rutin in the Leaves ofBoehmeria niveaHarvested in Different Regions of South Korea by HPLC-UV

Phytochemical analysis of Boehmeria nivea (Bn) leaves by medium pressure liquid chromatography led to the isolation of a flavonoid glycoside identified by spectroscopic analysis as rutin. The amount of rutin in the leaves of Bn harvested from nine regions in South Korea (Bn 1-9) which were collected on the months of June, July, August, and September was determined by HPLC-UV analysis. A gradient elution program that utilizes a Discovery® C18 (4.6 × 250 mm, 5 μm) column and mobile phase composed of 1% acetic acid-water: acetonitrile (90:10 to 60:40 for min) was followed. The injection volume and flow rate were 10 μl and 1 mL/ min, respectively. UV detection was set at 350 nm. Results show that Bn-8 harvested in September reported the highest content of rutin among the samples analyzed. This study provides a basis for the optimal harvest time of Bn which maximizes the yield of rutin.

Characterization of a novel yeast species Metschnikowia persimmonesis KCTC 12991BP (KIOM G15050 type strain) isolated from a medicinal plant, Korean persimmon calyx (Diospyros kaki Thumb)

The yeast strain Metschnikowia persimmonesis Kang and Choi et al., sp. nov. [type strain KIOM_G15050 = Korean Collection for Type Cultures (KCTC) 12991BP] was isolated from the stalk of native persimmon cultivars (Diospyros kaki Thumb) obtained from different regions of South Korea and was characterized phenotypically, genetically, and physiologically. The isolate grew between 4 and 40 °C (optimum temperature: 24–28 °C), pH 3–8 (pH optimum = 6.0), and in 0–4% NaCl solution (with optimal growth in absence of NaCl). It also exhibited strong antibiotic and antimicrobial activities. Morphologically, cells were characterized by the presence of long, needle-shaped ascospores. Based on 18S ribosomal DNA gene sequence analysis, the new species was found to belong to the genus Metschnikowia as a sister clade of Metschnikowia fructicola. We therefore conclude that this yeast isolate from D. kaki is a new member of the genus Metschnikowia and propose the name M. persimmonesis sp. nov. This strain has been deposited in the KCTC for future reference. This discovery provides a basis for future research on M. persimmonesis sp. nov., including its possible contribution to the medicinal properties of the host persimmon plant.

Study of 1-min rain rate integration statistic in South Korea

The design of millimeter wave communication links and the study of propagation impairments at higher frequencies due to a hydrometeor, particularly rain, require the knowledge of 1-min. rainfall rate data. Signal attenuation in space communication results are due to absorption and scattering of radio wave energy. Radio wave attenuation due to rain depends on the relevance of a 1-min. integration time for the rain rate. However, in practice, securing these data over a wide range of areas is difficult. Long term precipitation data are readily available. However, there is a need for a 1-min. rainfall rate in the rain attenuation prediction models for a better estimation of the attenuation. In this paper, we classify and survey the prominent 1-min. rain rate models. Regression analysis was performed for the study of cumulative rainfall data measured experimentally for a decade in nine different regions in South Korea, with 93 different locations, using the experimental 1-min. rainfall accumulation. To visualize the 1-min. rainfall rate applicable for the whole region for 0.01% of the time, we have considered the variation in the rain rate for 40 stations across South Korea. The Kriging interpolation method was used for spatial interpolation of the rain rate values for 0.01% of the time into a regular grid to obtain a highly consistent and predictable rainfall variation. The rain rate exceeded the 1-min. interval that was measured through the rain gauge compared to the rainfall data estimated using the International Telecommunication Union Radio Communication Sector model (ITU-R P.837–6) along with the empirical methods as Segal, Burgueno et al., Chebil and Rahman, logarithmic, exponential and global coefficients, second and third order polynomial fits, and Model 1 for Icheon regions under the regional and average coefficient set. The ITU-R P. 837-6 exhibits a lower relative error percentage of 3.32% and 12.59% in the 5- and 10-min. to 1-min. conversion, whereas the higher error percentages of 24.64%, 46.44% and 58.46% for the 20-, 30- and 60-min. to 1-min., conversion were obtained in the Icheon region. The available experimental rainfall data were sampled on equiprobable rain-rate values where the application of these models to experimentally obtained data exhibits a variable error rate. This paper aims to provide a better survey of various conversion methods to model a 1-min. rain rate applicable to the South Korea regions with a suitable contour plot at 0.01% of the time.

Nutrient status and phytotoxicity analysis of goat manure discharged from farms in South Korea

ABSTRACTThe present study evaluated the phytotoxicity effect of goat manure (GM) collected from six different regions in South Korea, namely, Chupungnyeong (T1), Hoengseong (T2), Goesan (T3), Sancheong (T4), Jangsu (T5) and Namwon (T6). Phytotoxicity was assessed by means of the analysis of germination index (GI), relative seed germination (RSG), relative root elongation (RRE) and vigor index (VI) using five commercial crop varieties, namely, sesame (Sesamum indicum L.), chrysanthemum (Chrysanthemum indicum L.), carrot (Daucus carota), radish (Raphanus sativus) and cabbage (Brassica rapa). Physico-chemical parameter values were recorded at appreciable levels in all GM extracts. The effect of seedling growth was significantly different (p ≤ .05) due to the variability of nutrient content and phytotoxic effect of the extracts on the different crop seeds. Of the extracts, Goesan (T3) and Sancheong (T4) recorded the best results in the range of GI (%) (54.1–128.8) and VI (930.7–1044) and GI (%) (70.1–167.3) and VI (609.2–3034), respectively, and also showed no inhibitory effect in any of the crop seeds. Overall results also revealed that radish crops showed excellent and non-phytotoxic results in all manure extracts compared to the other crops.

Occurrence of hydrangea ringspot virus and hydrangea chlorotic mottle virus in hydrangea plants in South Korea

Approximately 25 species of Hydrangea, often grown for cut flowers and landscaping, are widely distributed in Asia, the Americas, Europe, and South Africa and can be affected by multiple viruses. To identify any viruses affecting hydrangea populations in South Korea, we analyzed symptomatic samples from three different regions in South Korea using RT-PCR and sequenced the amplified products. From the 211 hydrangea plants sampled with virus-like symptoms such as chlorotic mottle, chlorotic and brown spots on the leaves and distortion of leaves, hydrangea ringspot virus (HdRSV) was found in 33 plants, and hydrangea chlorotic mottle virus (HdCMV) was detected in 10; two plants were co-infected with HdRSV and HdCMV. The coat proteins of HdRSV and HdCMV had the greatest amino acid sequence homology to HdRSV Hyd-CZ (98.7 % identity, GenBank accession GQ265901) and HdCMV-US (97.9 % identity, GenBank accession DQ412999), respectively. To our knowledge, this study is the first report of HdRSV and HdCMV infection in hydrangea plants in South Korea.

Microflora of phytopathogen-transferring Bradysia agrestis: a step toward finding ideal candidates for paratransgenesis

Owing to the effect of symbiotic gut bacteria on the proliferation of infectious disease-transferring insects and their potential as paratransgenic tools, their identification or securing their use in controlling insect vectors is urgently needed. Bradysia agrestis is one of the major plant epidemic vectors in East Asia; however, its normal microbiota remains unstudied. This research was primarily designed to secure promising candidates for use in a paratransgenic approach to phytopathogen control, as well as to provide a picture of the gut microbiota of wild-caught B. agrestis from a blight field. A total of 180 larvae from three different regions in South Korea were analyzed for their gut microfloral composition. Diverse bacterial strains were purely isolated based on morphological differences in microbiological media. We found a total of 64 bacterial strains in the B. agrestis midgut and analyzed their 16S rRNA gene sequences for molecular identification and phylogenetic characterization. Furthermore, the microbial diversity of each normal microbiota group was analyzed with various diversity indices. Bacterial biota including species diversity, richness or species distribution, species constituents, and dominance varied by each regional vector group. The most widely distributed species was Bacillus aryabhattai, and the most common genera were Bacillus and Microbacterium. These saprophytic bacteria were isolated from all regional groups and their potential as paratransgenic candidates for controlling B. agrestis-mediated plant disease is discussed.