• The Plant Pathology Journal
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• v.30 no.3
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• pp.323-329
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• 2014

Two cultivars Buram-3-ho (susceptible) and CR-Hagwang (moderate resistant) of kimchi cabbage seedlings showed differential defense responses to anthracnose (Colletotrichum higginsianum), black spot (Alternaria brassicicola) and black rot (Xanthomonas campestris pv. campestris, Xcc) diseases in our previous study. Defense-related hormones salicylic acid (SA), jasmonic acid (JA) and ethylene led to different transcriptional regulation of pathogenesis-related (PR) gene expression in both cultivars. In this study, exogenous application of SA suppressed basal defenses to C. higginsianum in the 1st leaves of the susceptible cultivar and cultivar resistance of the 2nd leaves of the resistant cultivar. SA also enhanced susceptibility of the susceptible cultivar to A. brassicicola. By contrast, SA elevated disease resistance to Xcc in the resistant cultivar, but not in the susceptible cultivar. Methyl jasmonate (MJ) treatment did not affect the disease resistance to C. higginsianum and Xcc in either cultivar, but it compromised the disease resistance to A. brassicicola in the resistant cultivar. Treatment with 1-aminocyclopropane-1-carboxylic acid (ACC) ethylene precursor did not change resistance of the either cultivar to C. higginsianum and Xcc. Effect of ACC pretreatment on the resistance to A. brassicicola was not distinguished between susceptible and resistant cultivars, because cultivar resistance of the resistant cultivar was lost by prolonged moist dark conditions. Taken together, exogenously applied SA, JA and ethylene altered defense signaling crosstalk to three diseases of anthracnose, black spot and black rot in a cultivar-dependent manner.

• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.33-40
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• 1998

The phenolic acids in needles of five pine species such as Pinus densiflora, P. thunbergii. P. virginiana. P. rigida. and P. koraiensis were analyzed seasionally (March, June, September and December) in order to investigate the resistant factors against pine gall-midge(Thecodiplosis japonensis Uchida et Inouye). The interrelation of resistance to pine gall-midge and the content of phenolic acids in pine needles was investigated in the artificial hybride pine species. The contents of salicylic acid in susceptible species (P. densiflora and P. thunbergii) to pine gall-midge which watered with salicylic acid solution in a pot was determined. The results can be concluded as follows, 1. There was a little change in total phenolic constituents of resistant and susceptible pines seasonally. The each content of benzoic acid, salicylic acid and p-hydroxybenzoic acid in June was the highest through four seasons. 2. In June, resistant species showed higher content of salicylic acid than susceptible species, while the content of gallic acid was the highest in December. 3. Among the 21 artificial hybrids(P. densiflora ${\times}$ P. virginiana. P. thunbergii ${\times}$ P. virginiana), the hybrides of the higher salicylic acid content showed the lower rate of pine gall formation. 4. Pine gall formation of the susceptible species which were watered with salicylic acid solution remarkably decreased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.3
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• pp.264-273
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• 2007

In order to examine the cross-tolerance of two chilling-tolerant cultivars (Donganbyeo and Heukhyangbyeo) and two chilling-susceptible cultivars (Hyangmibyeo and Taekbaekbyeo) to salt, paraquat, and drought, changes of physiological response and antioxidant enzymes were investigated. The seedlings were grown in a growth chamber until the 4-leaf stage. The seedlings were exposed to chilling at $5^{\circ}C$ for 3 days. For drought treatment, the seedlings were subjected to drought by withholding water from plants for 5 days. For paraquat study, plants were sprayed with $300{\mu}M$ paraquat. For the salt stress, the seedlings were transferred to the Hoagland's nutrient solution containing 0.6% (w/v) NaCl for 4 days. Chilling-tolerant cultivars showed cross-tolerant to other stresses, salt, paraquat, and drought in physiological parameters, such as leaf injury, chlorophyll a fluorescence, and lipid peroxidation. The baseline levels of antioxidative enzyme activities, catalase (CAT) and peroxidase (POX) activities in chilling-tolerant cultivars were higher than in the chilling-susceptible cultivars. However, there were no differences in ascorbate peroxidase (APX) and glutathione reductase (GR) activities between chilling-tolerant and -susceptible cultivars in untreated control. CAT activity in chilling-tolerant cultivars was higher than that in chilling-susceptible cultivars during chilling, salt, and drought treatments, but not during paraquat treatment. However, other antioxidative enzymes, APX, POX, and GR activities showed no significant differences between chilling-tolerant and -susceptible cultivars during chilling, salt, paraquat, and drought treatments. Thus, it was assumed that CAT contribute to cross-tolerance mechanism of chilling, salt, and drought in rice plants.

• Korean Journal of Weed Science
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• v.17 no.4
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• pp.400-406
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• 1997

Greenhouse studies were conducted to evaluate the tolerance of 42 pepper cultivars to postemergence applications of bentazon [3-(1-methylethyl)-(1H)-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide]. Cultivars, Jopoong, Singsing House, Sweet Green, Kwangbok, and Ilcheon showed relatively tolerant response to bentazon, while cultivars, Dahhong, Early Glory, Korea, Cheongyang, Nostalgia, and Daejanggyeong were susceptible ones to it. At rates over 2.40 kg ai/ha, the tolerant cultivars appeared to be clearly or more tolerant than the susceptible cultivars. For the determination of growth inhibition by bentazon, the concentration required to reduce growth by 50% (GR_(50)) was 2.00 to 2.40 kg ai/ha for susceptible cultivars, and 10.00 to 12.00 kg ai/ha for tolerant cultivars. Moreover, the herbicide rate required to inhibit growth by 50% $(I_{50})$ was 2.40 kg ai/ha for susceptible cultivars and 9.60 kg ai/ha for tolerant cultivars, respectively. On the $I_{50}$ and $GR_{50}$ estimates of growth, the tolerant cultivars were 5- to 6-fold more tolerant to bentazon than susceptible ones.

• Korean journal of applied entomology
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• v.31 no.2
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• pp.144-152
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• 1992

The juvenile hormone(JH) titers and juvenile hormone esterase (JHE) activities were mea¬sured in larval homogenates of the chestnut gall waL,J, Dryocosmus kuriphilus Yasumatsu, parasiting a susceptible and two resistant chestnut ( Cheuk-Pa, and Dan- Tak) varieties by GLC, Galleria wax test and Liquid scintilation counter. JH of the chestnut gall wasp was identified as JH- I. Their juvenile hormone titers were 35,800 GU/g(Cheuk-Pa), 30,900 GU/g (Dan-Tak), and 28,600 GU/g(susceptible variety). The juvenile hormone esterase activities were 1.48 n mole/min/ml(Cheuk-Pa), 1.63 n mole/min/ml(Dan- Tak), and 1.89 n mole/mini ml(susceptible variety). JH titer activity of the chestnut gall wasp parasiting resistant varie¬ties were higher than that from susceptible, whereas their JHE activity was higher in those from susceptible variety than those from resitant varieties. JH titer and JH specific esterase activity was inversely proportional.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.500-510
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• 2023

In this study, lactic acid bacteria were isolated from 21 top-selling probiotic products on Korean market and their antimicrobial resistance were analyzed. A total 152 strains were claimed to be contained in these products and 70 isolates belonging to three genera (Bifidobacterium, Lactobacillus, and Lactococcus) were obtained from these products. RAPD-PCR showed diversity among isolates of the same species except for two isolates of Lacticaibacillus rhamnosus from two different products. The agar dilution method and the broth dilution method produced different MICs for several antimicrobials. With the agar dilution method, five isolates (three isolates of Bifidobacterium animalis subsp. lactis, one isolate of B. breve, one isolate of B. longum) were susceptible to all nine antimicrobials and 15 isolates were multi-drug resistant. With the broth microdilution method, only two isolates (one isolate of B. breve and one isolate of B. longum) were susceptible while 16 isolates were multi-drug resistant. In this study, only two AMR genes were detected: 1) lnu(A) in one isolate of clindamycin-susceptible and lincomycin-resistant Limosilactobacillus reuteri; and 2) tet(W) in one tetracycline-susceptible isolate of B. longum B1-1 and two tetracycline-susceptible isolates and three tetracycline resistant isolates of B. animalis subsp. lactis. Transfer of these two genes via conjugation with a filter mating technique was not observed. These results suggest a need to monitor antimicrobial resistance in newly registered probiotics as well as probiotics with a long history of use.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.70.2-70
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• 2003

To evaluate the resistance to crown gall in grape rootstocks, cuttings from twenty seven grape rootstocks were inoculated with Agrobacterium vitis Cheonan 493 and size of galls from grapevines was measured in a greenhouse. Tumors were formed in all varieties of grape rootstocks tested in this study and no grape rootstock variety was immune to crown gall. Tumors were found on the stems of all plants tested in '196-17'and '41B' Based on measuring size and weight of galls formedon the stem of grape rootstocks, '779P' was extremely susceptible to crown gall. Some varieties such as 'Gloire', '140R', '101-l4M', '3309C', and '333EM' found to be resistant, while '99R', '1447P', 'Rupestris du lot', '110R', 'Freedom', and '41B'were susceptible and '1103P', '5C', '420A', 'Golia', and '5BB' were moderately susceptible to crown gall.

• Korean Journal Plant Pathology
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• v.11 no.4
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• pp.318-323
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• 1995

The effect of AF-toxin I produced by the strawberry pathotype of Alternaria alternata on the protein synthesis of susceptible strawberry protoplasts was examined by using the radiolabeled amino acids. The incorporation of the radiolabeled amino acids into newly synthesized proteins in the strawberry protoplasts was stimulated by the toxin treatment at relatively low concentrations (2.2$\times$10-11 to 2.2$\times$10-9 M), but not at higher concentrations (2.2$\times$10-8 to 2.2$\times$10-6 M). An one-dimensional SDS-polyacrylamide gel electrophoresis revealed no detectable differences in the proteins synthesized in both the toxintreated and untreated protoplasts. The susceptible strawberry protoplasts were treated with AF-toxin I and stained with Fluostain I to detect the extracellular polysaccharides. The toxin treatment induced the accumulation of extracellular polysccharides in a dose-dependent manner. These results indicate a transient activation of cellular metabolism in the susceptible cells by the toxin exposure.

• Natural Product Sciences
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• v.10 no.6
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• pp.325-329
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• 2004

The composition of essential oil from O. javanica was analyzed by gas chromatography-mass spectrometry. Using the broth dilution method and disk diffusion test, anti-microbial activities of the oil fraction and its main components were evaluated against various antibiotic-susceptible and resistant strains of pathogenic microorganisms. As a result of GC-MS analysis, 57 compounds, including ${\alpha}-terpinolene$ (28.1%), dl-limonene (16.0%), ${\gamma}-terpinene$ (10.3%), ${\beta}-pinene$ (9.7%) and ${\alpha}-pinene$ (6.0%) were identified in the essential oil fraction. The essential oil fraction of O. javanica and its main components exhibited significant inhibitory activities, particularly against Candida albicans (antibiotic-susceptible strains) and Streptococcus pneumoniae (antibiotic- susceptible and resistant strains). The main components of the O. javanica oil fraction displayed different patterns of activity against the three tested Candida species as exemplified by the differential minimum inhibiting concentration (MIC) values. The disk diffusion test showed that the activities were dose dependent.

• The Plant Pathology Journal
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• v.16 no.2
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• pp.105-109
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• 2000

The Pi-b is the rice gene conferring race specific resistance to the blast fungus Magnaporthe grisea race having a corresponding avirulence gene, AVR-Pi-b. All resistant cultivars have two copies of the Pi-b gene, but susceptible cultivars have a single copy of the gene. About 1 Kbp insertion sequence was detected in the open reading frame of the Pi-b gene from the susceptible cv. Nipponbare. The nature of insertion sequence was identified as a solo long terminal repeat (LTR) of new rice Tyl-copia-like retrotransposon. LTR was widely distributed in the rice genome. Various types of different patterns of restriction fragment length polymorphism of LTR were detected in indica cultivars, whereas a single type was detected from japonica cultivars. The insertion of LTR sequence in the Pi-b gene in the susceptible cultivar suggested that retrotransposon-mediated insertional mutation might played an important role in the resistance breakdown as well as evolution of resistance genes in rice.