• The Plant Pathology Journal
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• v.18 no.3
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• pp.138-141
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• 2002

A promising biocontrol agent, A2l-4, against Phytophthora blight of pepper was selected from 351 bacterial isolates collected from rhizosphere soils and roots of onion (Allium fistulosum L.). The isolate A21-4 was identified as Serratia plymuthica based on its 16S rRNA sequence and key characteristics as compared with that of an authentic culture of S. plymuthica (ATCC No. 6109D01). The isolate readily colonized on roots of various crops including pepper when inoculated on seed and not. Strain A2l-4 showed narrow spectrum of antibiotic activity, as revealed in its strong inhibitory activity to the genera Pythium and Phytophthora, but not to Fuasrium and Rhizoctonia. In pot experiments, none of the pepper seedlings treated with A2l-4 were infected by Phytophthora capsici, while 86% of the control plants were killed by the pathogen.

• Journal of the Korean Society of Tobacco Science
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• v.24 no.1
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• pp.7-12
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• 2002

During the screening or antiviral substances having inhibitory effect on tobacco mosaic virus(TMV) infection to tobacco plants, we found that a bacterial isolate, KTB61, which was identified as a Pseudomonas sp., strongly inhibited the formation of TMV local lesions. When the culture filtrate from KTB61 was applied on the upper surface of leaves of N. tabaccum Xanthi-nc tobacco at the same time of or 24 hours before TMV inoculation, almost complete inhibition was achieved. Incidence of systemic TMV infection to the susceptible tobacco cultivar, NC82, was reduced by 95% when TMV was inoculated onto the upper surface of leaves 24 hours after spraying the culture filtrate. Also 75∼80% of inhibitory effect was obtained by the inoculation of TMV onto the under surface of the leaves treated with culture filtrate 24 hours beforehand. In field trials, the TMV infection was reduced by 96.5% when the tobacco seedlings, N. tabaccum cv. NC82, were soaked with culture filtrate before transplanting.

• Animal cells and systems
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• v.9 no.1
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• pp.37-40
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• 2005

In okra Macrophomina phaseolina and Furasium verticilloides cause collar-rot, seedling-rot and other severe diseases at fruit maturing stages. These stages were located in all the components of the seeds. The seeds collected from seeds infected with Macrophomina phaseolina and Fusarium verticilloides revealed 100% infection. Such seeds resulted in pre- and post-emergence mortalities. Inoculated seeds also showed pre- and post-emergence death of the seedlings. The fungi seed-transmitted showed disease symptoms at different growth of okra plant. Fusarium verticilloides causes the wilt and Macrophomina phaseolina causes the collar-rot. Until now seed transmission of these fungi have not been studied. Hence, in the present study an attempt has been made to fill this lacunae.

• Journal of Plant Biology
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• v.36 no.2
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• pp.177-182
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• 1993

The root nodules of Elaeagnus umbellata were coralloid-shape due to repeated dichotomous branching of nodule meristem. The filamentous endophyte with vesicle cluster ranging from 30 ${\mu}{\textrm}{m}$ to 60 ${\mu}{\textrm}{m}$ in diameter was present only in the cortical cells. The isolated endophytes in vitro culture showed typical Frankia morphology, consisting of highly branched hyphae ranging from 0.8 ${\mu}{\textrm}{m}$ to 1.0 ${\mu}{\textrm}{m}$ in diameter, terminal and intrahyphal sporangia varing in shape and size up to 60 ${\mu}{\textrm}{m}$ in length and laminated vesicles. Its infectivity and effectivity were confirmed by induction of nitrogen-fixing root nodules on the inoculated seedlings of two Elaeagnus species. Consequently, the isolate was confirmed as a true symbiont of Elaeagnus umbellata root nodule and named Frankia EuIK1.

• Korean Journal of Microbiology
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• v.27 no.4
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• pp.398-403
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• 1989

The root nodule of Canavalia lineta was classified as a determinate nodule and the symbiont as a Rhizobium-bacteriod based on their morphological characteristics. Isolated encosymbiont was similar both to R. leguminosarum and R. meliloti in its peritrichous arrangement of flagella and some of the physiological characteristics. Compared to control plants, Canavalia seedlings inoculated with the isolate grew normally due to induced root nodules, confirming isolate's infectivity and effectivity. Characteristics of the reisolated endosymbiont from induced root nodule were identical to those of the first isolate, indicating the nodules were induced by the first isolate. From these results, it was confirmed that Rhizobium strain isolated from the root nodules of Canavalia lineata was a real symbiont, and was named Rhizobium sp. SNU003.

• Journal of Applied Biological Chemistry
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• v.57 no.2
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• pp.153-157
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• 2014

Plant-growth-promoting rhizobacteria can affect plant growth by various direct and indirect mechanisms. This study was conducted to determine the ability of some rhizobacterial strains to enhance the seed germination of Lactuca sativa (lettuce) and Raphanus sativus (radish). Seeds were inoculated using a spore suspension ($1{\times}10^7cfumL^{-1}$) and incubated in a growth chamber at $28^{\circ}C$ under dark conditions and 65% RH. Azotobacter chroococcum and LAP mix inoculation increased the plumule length of L. sativa by 1.3, 0.8, and 0.7 cm, respectively, in comparison to the uninoculated control. Pseudomonas putida showed an increase of only 0.6 cm in plumule length when compared to the control. Inoculation of A. chroococcum, P. putida, and LAP mix enhanced the seed germination rate of R. sativus, by 10, 5, and 30%, respectively, in comparison with the uninoculated seeds. The results demonstrated that the inoculation of seeds by select rhizobacterial strains showed remarkable enhancement to the radicle length of lettuce and radish seedlings.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.25-28
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• 1994

One hundred fifty four our of 262 isolates of Fusarium oxysporum obtained from healthy plant tissues of various crops and their rhizosphere soil were found to be nonpathogenic to cucumber plants. The nonpathogenic isolates were frequently found from sesame plant tissues and rhizosphere soil, but less from healthy plant tissues of cucumber and water melon. When the 154 nonpathogenic isolates were preinoculated into cucumber seedlings, and then challenge-inoculated with Fusarium wilt pathogen, 21 isolates protected effectively cucumber plants from Fusarium wilt infections. A year later, 9 out of 21 isolates fully sustained their protective effect. Among 9 isolates showing good protective effects, 7 were isolates from cucumber plants. These 9 isolates except 1 isolate, were not pathogenic to water melon, chines melon, tomato and sesame.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.29-33
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• 1994

One hundred fifty four out of 262 isolates of Fusarium oxysporum obtained from healthy plant tissues of various crops and their rhizosphere soil were found to be nonpathogenic to cucumber plants. The nonpathogenic isolates were frequently found from sesame plant tissues and rhizosphere soil, but less from healthy plant tissues of cucumber and water melon. When the 154 nonpathogenic isolates were preinoculated into cucumber seedlings, and then challenge-inoculated with Fusarium wilt pathogen, 21 isolates protected effectively cucumber plants from Fusarium wilt infections. A year later, 9 out of 21 isolates fully sustained their protective effect. Among 9 isolates showing good protective effects, 7 were isolates from cucumber plants. These 9 isolates, except 1 isolate, were not pathogenic to water melon, chinese melon, tomato and sesame.

• The Korean Journal of Mycology
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• v.51 no.2
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• pp.121-125
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• 2023

In this study, we examined the ectomycorrhiza (ECM) formed by a species of the genus Tuber, T. koreanum, with two indigenous Korean oak species, Quercus acutissima and Q. dentata. T. koreanum showed a high colonization rate for both oak species, with a higher mean colonization rate observed for Q. acutissima. The mycorrhizal characteristics of T. koreanum were described, revealing distinct morphological and anatomical differences between the ECM formed with the two host plants. This study is significant because it is the first to elucidate ECM formations of T. koreanum in indigenous oak trees. However, further studies are required to differentiate the ECM associations formed by T. koreanum from those of other Tuber species.

• Journal of Bio-Environment Control
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• v.29 no.1
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• pp.96-102
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• 2020

Fusarium wilt caused by Fusarium oxysporum is a devastating disease limiting production of watermelon in Korea. The best way to control diseases is to use resistant gourd rootstock on watermelon. This study was conducted to establish an efficient screening method for resistant bottle gourd to Fusarium oxysporum f. sp. lagenaria. To develop an efficient inoculation method, incubation temperature after inoculation (15, 20, 25, and 30℃), inoculum concentration (1 × 10⁵, 5 × 10⁵, 1 × 10⁶, and 5 × 10⁶ conidia·mL^-1), and growth stages of seedlings (7, 10, 13, and 16 days) was investigated. Disease development of Fusarium wilt of bottle gourd was little affected by differences in incubation temperature and growth stages of seedlings. But resistant lines were more susceptible and appeared more severe symptoms at the higher inoculation level. Taken together, we suggest that an effective screening method for resistant gourd plant to Fusarium wilt is to dip the roots of 10-day old seedlings in spore suspension of 1 × 10⁵ - 1 × 10⁶ conidia·mL^-1, for 30 min, to transplant the seedlings into a non-infected soil, and then to incubate the inoculated plants in a growth room at 25℃ for 3 weeks to develop Fusarium wilt.