• Research in Plant Disease
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• v.9 no.1
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• pp.52-56
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• 2003

It was conducted to investigate the effect of rice downy mildew (RDM) infection to plant growth and yield components in water seeding stage, and to screen of varietal resistance to downy mildew. Being infected by rice downy mildew, chlorotic spot appeared in the leaf and leaf length was shortened. As the infected rice was growing, internode was not elongated properly and was deformed, and then panicle was not arised or mal-formed. Plant height of infected rice was shortened at all growth stage, and while the number of tillers of infected rice was more decreased than that of healthy plant before maximum tillering stage, and that of infected rice was more increased after heading stage. While the number of internode of infected tiller was much increased than that of healthy tiller internode length of infected tiller was shorter. As the rice infected by RDM severely, the number of panicles per square meter and ripening of rice was more decreased and yield of rice was extremely much decreased. As result of the varietal resistance screening with rice seedling, Geyh-wabyeo and Donjinbyeo were resistant varieties to downy mildew.

• The Korean Journal of Malacology
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• v.14 no.2
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• pp.85-90
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• 1998

The effects of methanol extracts of plant molluscicide, Brassaia actinophylla (Araliaceae) had been assessed on development of eggs f snails, Biomphalaria glabrata and Indoplanorbis exustus at sublethal concentrations. Results revealed that the administration of 10mg/l of B. actionophylla caused some alterations in embryos of both species. Niclosamide (0.004 mg/l) also arrested the development of embryos in B. glabrata ans I. exustus. It can be concluded that B. actinophylla has a potential use as an avicidal agent in the control of the snail intermediate hosts of schistosomiasis.

• Journal of Plant Biotechnology
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• v.38 no.2
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• pp.125-129
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• 2011

Environmental risk assessment (RA) is essential prior to the environmental release of GM crops. RA, however, costs at least 7 to 15 million US dollars and requires several years to complete field tests. Therefore, it is strongly suggested that developers of GM crops must consider all criteria for RA at the beginning stage of the development if it aims for commercialization. Previous review papers have pointed out that the "death valley" for the commercialization of GM crops is the screening stage of early GM events since many candidates are given up due to insufficient data on the molecular characterization of a GM event such as inserted gene's copy number, position of inserted site of a chromosome, flanking sequence of recombinant T-DNA, rearrangement of chromosome, and knock out of endogenous gene of host plant. Recently, Rural Development Administration (RDA) in South Korea has launched a Grand National Project named as "Next Generation of BioGreen 21 Project" from 2011 to 2020 and research funding for the development of global GM crops has been allocated to accelerate the commercialization of GM crops. In this regard, I strongly suggest that researchers involved in the development of GM crops for commercialization must conduct RA by themselves at the screening stage of pre-GM event based on the data for molecular characterization.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.384-389
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• 1992

Bacillus sp. YBL-7 which had been isolated from ginseng root-rot suppressive soil was able to antagonize Fusarium solani causing ginseng root-rot by their antibiotic substance. In order to develop multifunctional antagonist on Bacillus sp. YBL-7 as a biocontrol agent against Fusarium salam', optimal conditions for protoplast transformation system of Bacillus sp.YBL-7 by the vector plasmid pE194 were investigated. The protoplasts of Bacillus sp. YBL-7 were obtained at best efficiency by treatment with 200${\mu}g$/ml of lysozyme in the pH 7.0 of SMM buffer for 90 minutes at $40^{\circ}C$. The cell wall of the protoplast was regenerated on the agar plate containing 1.2% agar and 0.7 M mannitol. Under the best condition for protoplast formation and regeneration, the optimal transformation was achieved with 40% polyethylene glycol (M.W. 4000) treatment for 10minutes. The vector plasmid pE194 showed the best transformation frequency at 5$\mu$g/ml of final concentration. The pE194 was very stable over 80% in the transformants.

• Korean Journal of Environmental Biology
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• v.22
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• pp.86-92
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• 2004

The marine viral density in the Gwangyang Bay was abundant about 2.0${\times}$10$^{8}$ particles ml$^{-1}$ . For each season, viral abundances were recorded from 9.0${\times}$10$^{8}$ particles ml$^{-1}$ in summer to 0.7${\times}$10$^{6}$ particles ml$^{-1}$ in winter. The spatial distributions of the viral, bacterial and phytoplankton biomass in the Gwangyang Bay were mostly highey in closed estuarine system (Station 2, 5, 10, 12, 16, 20) than open ocean system (Station 28, 38, 42, 46, 51), And the othey closed estuarine system (Station 22, 26, 32, 34) indicated higher viral abundances, lower bacterial and plankton biomass than open oceanic system. In depths of some stations, the bacterial abundances exceeded a hundred fold than viral abundances. Seasonal abundances of marine viruses and their host systems were dynamically changed, and their seasonal variations were closely correlated. In summer, viral and bacterial abundances were increased, and phytoplankton chlorophyll $\alpha$ concentrations were maintained in average values. In winter, viral and bacterial abundances were dramatically decreased, and chlorophyll a concentrations were decreased, but, immediately increased. The viral abundances were peaked in August 2001, and bacteyial abundance, in August 2001 and June 2002, while chlorophyll a concentrations were peaked in April. 2002. In total host and viral abundances, it was seemed that their pools were maintained to steady-states by viral mortality, and viral abundance maintained steady-states. In our assessments, this report is a unique research about marine viral ecology of the Gwangyang Bay in Korea.

• The Korean Journal of Pesticide Science
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• v.14 no.4
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• pp.473-477
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• 2010

Cucumber green mottle mosaic virus (CGMMV) is one of major plant viruses infecting cucurbitaceous crops via soil or infected seeds. This study investigate ecology of infection of CGMMV in soil, and control tactics of this virus with soil hygiene and crop rotation. This virus was survival to 50% in soil without host plants for 17 months and had high vitality in debris of infected plant over 1 year. Infection rate of CGMMV was 1.0~3.6% in control soil and 12~36% in soil transplanted with wounded root of watermelon. It showed that wounded root may affect severity of soil infection. Rotation between rice and watermelon caused dramatical reduction from 76.8% in repeated cultivation to 7.3% of progeny infection by CGMMV. Therefore, it is suggested that crop rotation be effective for control of CGMMV.

• Research in Plant Disease
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• v.21 no.4
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• pp.337-340
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• 2015

During July to November 2014, severe rust infection was consistently found on Peucedanum japonicum growing farm in Yeosu, Korea. The rust was observed mainly on lower leaf surfaces. Symptoms of typical plants included yellow-orange rust pustules were observed on the petiole and leaf surface with small yellowish to chlorotic lesions on the upper surface. No symptom was observed on flowers. Uredinia were occurred amphigenous on leaf surface, and occasionally caulicolous, scattered or loosely aggregate, rounded to oblong, 0.4 to 4 mm in diameter, covered by epidermis, then naked, surrounded by ruptured epidermis, pulverulent, and brown. Urediniospores were ovate-ellipsoid, ellipsoid or subglobose, light brown, 20 to $45{\times}15$ to $35{\mu}m$, walls 2 to $4{\mu}m$ thick. The resulting sequences were deposited in GenBank with accession No. KT778808, KT778809, and KT778810, respectively. Since this was the first accession of 28S sequence Puccinia jogashimensis, there was no exact match in GenBank nucleotide database. On the basis of the morphological characteristics and phylogenetic analyses of 28S rDNA, the fungus was identified as P. jogashimensis. To our knowledge, this is the first confirmed report on the occurrence of P. jogashimensis on P. japonicum in Korea.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.6
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• pp.437-444
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• 2003

Objective of this experiment was to investigate the role of strontium in intracellular processes in mung bean (Vigna radiata L.). Diamine oxidase (DAO) induction by $Sr^{2+}$ appeared to a decrease in putrescine levels correspondently. DAO activities in the hypocotyls were in a range of 0.5 to $1.8unit{\cdot}mg^{-1}\;protein{\cdot}min^{-1}$. The decrease in Put levels in the cotyledons might be partly resulted from Put degradation by DAO. It was observed that the accumulation of spermidine and spermine by $Sr^{2+}$ was in the range of 1 mM to 10 mM. Spermidine levels were 2 to 3 fold higher than in the absence of strontium. The increase in polyamine levels was observed not only on a basis of g fresh weight but also a RNA basis. These results demonstrated that the inhibitory action of $Sr^{2+}$ may be closely related with polyamine metabolism as well as diamine oxidation and polyamine accumulation.

• Korean Journal of Organic Agriculture
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• v.21 no.4
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• pp.669-684
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• 2013

This study was investigated to evaluate the effects of biodiversity and pest insect occurrence by soil surface management methods such as green manure crop, grass planting and clean-tilled crops on persimmon orchards. Green manure crop pests was investigated 7 species including Hypera postica, Laodephax striatellus, Megoura crassicauda, Aphis craccivora, Nephotettix cincticeps, Liriomyza sp., black spot and the most dangerous pest was H. postica but it did not damaged persimmon tree. Amount of pests and natural enemies dwelling soil covering plant was not difference between organic farming (hairy vetch planting) and conventional farming (natural weed). Homona magnanima occurred three times a year but it rarely damaged leaf of persimmon. Total adult moth catched by pheromone trap was 1,261 organic farm, 1,003 conventional farm and 621 clean-tilled farm. Grapholita molesta occurred four times a year but it also rarely damaged twig of persimmon. Number of collected invertebrate species and individuals on soil sample was follow as : 838 individuals of 22 species at organic farm, 421 individuals of 17 species at conventional farm and 381 individuals of 15 species at clean-tilled farm. The richness index was lined up by organic farm 3.12> conventional farm 2.65> clean-tilled farm 2.36.

• Research in Plant Disease
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• v.8 no.3
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• pp.179-183
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• 2002

to investigate occurrence of kiwifruit bacterial canker disease,172 kiwifmit orchards in Jeonnam and Gyeong-nam provinces were surveyed from March to April in 1999. In the south coast region of Korea, such as Haenam, Wando, Jindo, Jangheung, and Bosuns, red-rusty brown bacterial oozes were observed in 17 kiwifvuit orchards. Disease incidences varied from 2.2% to 100% depending on various regions. Total 22.8 ha of kiwifruit orchards were destroyed by occurrence backerial canker at 1999 in Korea. Orchard in Wando, Jindo, and Goheng were severely damaged in 1999. The seasonal variation of bacterial canker incidence was also investigated from 1996 to 1997 on leaves, vines and twigs of kiwifruit. Red-rusty brown bacterial ooze was exuded from mid February or early March to late April in creaked site of vine and twig. The seasonal incidence of bacterial canker on leaves appeared from late April to late June, and rapidly increased during May, Optimum growth temperature of Pseudomonas sytingae pv. actinidiae was at $25^{\circ}C$ on King's B medium and did not grow at 33$^{\circ}C$. We suggest that spreading of bacterial canker was suppressed under the plastic flim and windbreak net house.