• The Plant Pathology Journal
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• v.28 no.1
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• pp.55-59
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• 2012

Northern stem canker caused by $Diaporthe$ $phaseolorum$ var. $caulivora$ ($Dpc$) has become a serious disease in soybean. The objectives of this study were to survey the existence of $Dpc$ on soybean in Korea, and to examine the potential pathogenicity of $Dpc$ in seed decay. One such isolate, SSLP-4, isolated from a field-grown plant of the Korean soybean cultivar Danbaekkong, was identified as $Dpc$, based on its morphological and molecular characteristics by sequences of internal transcribed spacer (ITS), translation elongation factor (TEF) 1-${\alpha}$ and ${\beta}$-tubulin regions, as well as pathogenic analyses. Moreover, morphological and molecular analyses revealed that isolate SSLP-4 was nearly identical to $Dpc$ strains from the United States. Pathogenicity tests on hypocotyls of soybean seedlings and detached leaves resulted in typical symptoms of soybean northern stem canker and inoculation on plants at R5-R7 stage caused seed decay. All results suggest that the $Dpc$ strain SSLP-4 can cause both stem canker and seed decay on soybean. Thus, the SSLP-4 isolate has the potential to contribute greatly to understanding of host plant resistance mechanisms, both at vegetative and reproductive growth stages in soybean.

• Journal of Plant Biotechnology
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• v.46 no.4
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• pp.247-254
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• 2019

Flavonoids are widely distributed secondary metabolites in plants that have a variety biological functions, as well as beneficial biological and pharmacological activities. In barley (Hordeum vulgare L.), for example, high levels of saponarin accumulate during primary leaf development. However, the effect of saponarin biosynthetic pathway genes on the accumulation of saponarin in barley is poorly understood. Accordingly, the aim of the present study was to examine the saponarin contents and expression levels of saponarin biosynthetic pathway genes [chalcone synthase (CHS), chalcone isomerase (CHI), and UDP-Glc:isovitexin 7-O-glucosyltransferase (OGT)] during early seedling developmental and under several abiotic stress conditions. Interestingly, the upregulation of HvCHS, HvCHI, and HvOGT during early development was associated with saponarin accumulation during later stages. In addition, exposure to abiotic stress conditions (e.g., light/dark transition, drought, and low or high temperature) significantly affected the expression of HvCHS and HvCHI but failed to affect either HvOGT expression or saponarin accumulation. These findings suggested that the expression of HvOGT, which encodes an enzyme that catalyzes the final step of saponarin biosynthesis, is required for saponarin accumulation. Taken together, the results of the present study provide a basis for metabolic engineering in barley plants, especially in regards to enhancing the contents of useful secondary metabolites, such as saponarin.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.4 no.4
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• pp.231-240
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• 2000

Effects of Jasmonic Acid and Wounding on Polyphenol Oxidase Activity in Senescing Tomato Leaves The effects of jasmonic acid(JA) and wounding on polyphenol oxidase(PPO) during leaf senescence was investigated by measuring the PPO activity in detached tomato(Lycopersicon esculentum Mill.) leaves of two-week-old seedlings. The PPO activity in the detached senescing leaves increased significantly in the dark. The leaf segments responded to the application of JA with accelerated senescence, as indicated by the loss of chlorophyll and rapid increase in the PPO activity. The senescence-promoting action of JA differed in the light and dark. Wounding the detached senescing leaves by scraping surface segments or making punctures with needles considerably delayed the loss of chlorophyll and had a significant effect on the PPO activity, the amounts of which were roughly proportional to the intensity of the wounding. In the dark, the combination of wounding plus JA resulted in stable levels of chlorophyll and PPO. JA and ABA acted similarly in both unwounded and wounded leaves, however, the amount of chlorophyll and PPO in the wounded segments was always higher than in the respective controls. JA was found to eliminate the senescence-retarding action of benzyladenine. In a histochemical localization test, the PPO activity was found to be localized in the cell walls of the parenchyma tissue, thereby indicating moderate cytoplasmic reactions. In the JA-treated plants, the PPO activity was intense in the cells of the cortex and phloem parenchyma. Accordingly, based on these observations it would appear that PPO is a component of a defense response maker, whereas JA plays an integral role in the intracellular signal transduction involved in inducible defense mechanisms.

• BMB Reports
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• v.43 no.1
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• pp.9-16
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• 2010

The promoters of OsCaM1 and OsCaM3 were characterized after sequencing and fused to the reporter gene, GUS. The constructs were then transformed into the tobacco plant. Histochemical analysis of GUS showed different expression patterns in pOsCaM1::GUS and pOsCaM3:: GUS transgenic plants. The expression of pOsCaM1::GUS in 4- to 15-day-old seedlings in particular was observed only in the root, while the expression of pOsCaM3::GUS was detected in both the cotyledons and root. Also, pRCaM1::GUS was detected in all the tissues surrounding the root system, while the presence of pOsCaM3::GUS was observed in the root, except in the root meristem. However, in mature transgenic plants, the expression of pOsCaM1::GUS and OsRCaM3::GUS was scarcely detected. Under wounding stress, the GUS activity of pOsCaM1 and pOsCaM3 was strongly induced, and the activity of pOsCaM3 especially, was retained for long periods. In the phloem, pOsCaM3 activity induced by hormone treatments and abiotic stresses was also identified.

• ALGAE
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• v.23 no.3
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• pp.241-250
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• 2008

Since seagrasses in the coastal and estuarine ecosystems achieve high levels of production, they require high inorganic carbon and nutrient incorporation. Thus, seagrasses may play a significant role in carbon and nutrient cycling in the coastal and estuarine ecosystems. To examine growth dynamics of Zostera marina L. environmental factors such as underwater irradiance, water temperature, and salinity, and biological parameters such as shoot density, biomass, shoot morphology, and leaf productivity were measured in two bay systems (Jindong Bay and Gamak Bay) on the southern coast of Korea. While underwater irradiance did not show distinct seasonal trend, water temperature at both sites exhibited clear seasonal trend throughout the experimental period. Shoot density increased dramatically during winter due to the increased seedlings through germination of seeds in Jindong Bay and due to the increased lateral shoots in Gamak Bay. Eelgrass biomass increased during winter and decreased during summer. Maximum biomass in Jindong Bay and Gamak Bay was 250.2 and 232.3 g dry weight m–a2, respectively. Carbon incorporation into the eelgrass leaf tissues was estimated from productivity and leaf tissues carbon content. The calculated annual carbon incorporations at the Jindong Bay and Gamak Bay sites were 163 and 295 g C m–`2 y–`1, respectively. This high carbon incorporation into seagrass tissues suggests that seagrass habitats play an important role as a carbon absorber in the coastal and estuarine ecosystems.

• The Korean Journal of Mycology
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• v.3 no.2
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• pp.7-12
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• 1975

Three species of Pythium previously not recorded in Korea were found during 1975. Pythium spinosum Sawada was isolated from diseased cabbage seedlings, P. myriotylum Dreschl. was isolated from kidney bean and P. butleri Subramanium from cucumber, spinach, red bean and radish. Pathogenicity of isolates of P. butleri and P. myriotylum was confirmed in pathogenicity tests but P. spinosum appeared to be non-pathogenic. Several isolates failed to sporulate satisfactorily on cornmeal agar and some produced degenerate oogonia after sub-culturing on this medium. Sunflower seed agar was found to be a suitable alternative medium. The validity of previous records of P. debaryanum Hess in Korea is discussed.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.5
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• pp.407-410
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• 2001

This study was conducted to determine the optimal planting distance in cultivation of yacon (Polymnia sonchifolia Poeppig ＆ Endlicher). Plug seedlings were planted with 6 different plant densities of 80 $\times$ 60, 80 $\times$ 50, 70 $\times$ 50, 70 $\times$ 45, 70 $\times$ 40 and 60 $\times$ 45 cm. The plant height and the petiole length were increased with increasing the planting distance. The tallest plant height of yacon was 165.4cm with the plant density of 80 $\times$ 60 cm. However, branch number per plant, leaf number on main stem and stem diameter were not significantly difference among planting densities. Tuberous root was harvested 31.42 tons/ha in 70 $\times$ 50 cm spacing. The ratio of heavier tuberous roots than 200 g to total tuberous roots decreased significantly according to increase of planting density. Fresh weights of shoot and root, contain the crown bud, were decreased, as planting distance was shorter. Tuberous root number was fewer but its weight was heavier in wide planting than in dense planting. We think that optimal planting density is about 30,000 plants/ha, if it were to be 70 cm row spacing, intrarow spacing should calculate about 47cm.

• Journal of Microbiology and Biotechnology
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• v.17 no.4
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• pp.586-593
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• 2007

Seed coating by a phenazine-producing bacterium, Pseudomonas chlororaphis O6, induced dose-dependent inhibition of germination in wheat and barley seeds, but did not inhibit germination of rice or cucumber seeds. In wheat seedlings grown from inoculated seeds, phenazine production levels near the seed were higher than in the roots. Deletion of the gacS gene reduced transcription from the genes required for phenazine synthesis, the regulatory phzI gene and the biosynthetic phzA gene. The inhibition of seed germination and the induction of systemic disease resistance against a bacterial soft-rot pathogen, Erwinia carotovora subsp. carotovora, were impaired in the gacS and phzA mutants of P chlororaphis O6. Culture filtrates of the gacS and phzA mutants of P. chlororaphis O6 did not inhibit seed germination of wheat, whereas that of the wild-type was inhibitory. Our results showed that the production of phenazines by P. chlororaphis O6 was correlated with reduced germination of barley and wheat seeds, and the level of systemic resistance in tobacco against E. carotovora.

• Korean Journal of Environmental Biology
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• v.32 no.2
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• pp.95-101
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• 2014

In order to investigate effects of elevated $CO_2$ concentration and temperature on the ecological niche of Quercus serrata in Korea. We divided experimental condition in the greenhouse that are control (ambient condition) and treatment with elevated $CO_2$ (approximately 1.6 above than control) and increased air temperature (approximately $2.2^{\circ}C$ above than control). We measured twenty kind characters of seedlings and calculated the ecological niche breadth. As a result, the ecological niche breadth, treatment was widened in the light gradient than the control, was narrowed in the moisture and nutrient gradient. This is may be predicted when the global warming progress, Q. serrata is increases resistance to light environment, and decrease resistance to moisture and nutrient environment. According to the principal component analysis (PCA), control and treatment were arranged based on factor 1 and 2 in each environment gradients. Ecological response is involved variety characters. Among them, indicating that Characters of production is involved in many a parts.

• Plant Biotechnology Reports
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• v.5 no.3
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• pp.217-224
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• 2011

Non-heading Chinese cabbage (Brassica rapa L. ssp. chinensis) is a popular vegetable in Asian countries. The diamondback moth (DBM), Plutella xylostella (L.), an insect with worldwide distribution, is a main pest of Brassicaceae crops and causes enormous crop losses. Transfer of the anti-insect gene into the plant genome by transgenic technology and subsequent breeding of insect-resistant varieties will be an effective approach to reducing the damage caused by this pest. We have produced transgenic non-heading Chinese cabbage plants expressing the potato proteinase inhibitor II gene (pinII) and tested the pest resistance of these transgenic plants. Non-heading Chinese cabbages grown for 45 days on which buds had formed were used as experimental materials for Agrobacterium-mediated vacuum infiltration transformation. Forty-one resistant plants were selected from 1166 g of seed harvested from the infiltrated plants based on the resistance of the young seedlings to the herbicide Basta. The transgenic traits were further confirmed by the Chlorophenol red test, PCR, and genomic Southern blotting. The results showed that the bar and pinII genes were co-integrated into the resistant plant genome. A bioassay of insect resistance in the second generation of individual lines of the transgenic plants showed that DBM larvae fed on transgenic leaves were severely stunted and had a higher mortality than those fed on the wild-type leaves.