• Korean journal of applied entomology
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• v.46 no.1 s.145
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• pp.169-173
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• 2007

Root-knot nematode damage was found on yam, Dioscorea bulbifera in Andong Korea. From the root-knots, female nematodes were isolated and subjected to DNA sequence analysis. Sequence of cytochrome oxidase subunit II (COII) was analyzed from the genomic DNA of the isolate. COII locus size and sequence of the nematode isolate were similar to those of Meloidogyne javanica or M. incognita. However, an analysis of HinfI restriction site, a species-specific character between these two species, showed that the isolate did not match to either M. javanica or M. incognita.

• Journal of Plant Biotechnology
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• v.50
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• pp.163-168
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• 2023

Sweetpotato (Ipomoea batatas [L.]) is a globally important root crop cultivated for food and industrial processes. The crop is susceptible to the root-knot nematode (RKN) Meloidogyne incognita, a major plant-parasitic RKN that reduces the yield and quality of sweetpotato. Previous transcriptomic and proteomic analyses identified several genes that displayed differential expression patterns in susceptible and resistant cultivars in response to M. incognita infection. Among these, several sporamin genes were identified for RKN resilience. Sporamin is a storage protein primarily found in sweetpotato and morning glory (Ipomoea nil). In this study, transcriptional analysis was employed to investigate the role of sporamin genes in the defense response of sweetpotato against RKN infection in three susceptible and three resistant cultivars. Twenty-three sporamin genes were identified in sweetpotato and classified as group A or group B sporamin genes based on comparisons with characterized sweetpotato and Japanese morning glory sporamins. Two group A sporamin genes showed significantly elevated levels of expression in resistant but not in susceptible cultivars. These results suggest that the elevated expression of specific sporamin genes may play a crucial role in protecting sweetpotato roots from RKN infection.

• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.960-966
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• 2022

Lactic acid bacteria (LAB) exert antagonistic activity against root-knot nematodes, mainly by producing organic acids via carbohydrate fermentation. However, they have not yet been used for root-knot nematode (Meloidogyne incognita) control owing to a lack of economic feasibility and effectiveness. In this study, we aimed to isolate organic acid-producing LAB from kimchi (Korean traditional fermented cabbage) and evaluated their nematicidal activity. Among the 234 strains isolated, those showing the highest nematicidal activity were selected and identified as Lactiplantibacillus plantarum WiKim0090. Nematicidal activity and egg hatch inhibitory activity of WiKim0090 culture filtrate were dose dependent. Nematode mortality 3 days after treatment with 2.5% of the culture filtrate was 100%, with a 50% lethal concentration of 1.41%. In pot tests, the inhibitory activity of an L. plantarum WiKim0090-copper sulfate mixture on gall formation increased. Compared to abamectin application, which is a commercial nematicide, a higher control value was observed using the WiKim0090-copper sulfate mixture, indicating that this combination can be effective in controlling the root-knot nematode.

• Research in Plant Disease
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• v.18 no.4
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• pp.370-375
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• 2012

Ninety two pepper (Capsicum annuum L.) cultivars were screened for resistance to two common species of root-knot nematodes, Meloidogyne incognita and M. arenaria. All 92 pepper cultivars were resistant to M. arenaria (0-3 eggmass/plant) but were susceptible to M. incognita (76-678 eggmass/plant). Susceptibility to M. incognita were slightly differed; 'Geomok' and 'Shintaepung' had relatively less eggmass (<100 eggmass/plant) when compared to those 29 very susceptible culivars such as 'Bulggotcheoreum' (>300 eggmass/plant). Therefore, pepper is highly recommended as a high-valued rotation crop to only those greenhouses infested with M. arenaria, but should restrict for M. incognita.

• The Plant Pathology Journal
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• v.35 no.1
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• pp.51-62
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• 2019

A great variable response was observed when PP-3 and PP-J encumbered with 116 populations of root knot nematode (RKN) at two different temperatures ($25{\pm}2^{\circ}C$ and $30{\pm}2^{\circ}C$) and concentrations ($10^4$ and $10^5$ spores/ml). The PCR reaction amplified intergenic region between cytochrome oxidase subunit II gene (COII) and large subunit of rRNA gene (lrRNA) of the mitochondrial genome of different RKN species. The primer C2F3 and 1108 identified M. incognita with the highest frequency (52.6%) followed by M. javanica (36.8%) and M. arenaria (10.5%). The sizes of PCR products were 1.7 kb for M. incognita and M. javanica populations while populations of M. arenaria produced 1.1 kb fragment. The digestion with Hinf I yielded three different fragment length patterns on 1.5 % agarose gel. From current research it is concluded that intra-Meloidogyne genetic variability exist in RKN populations which have better encumbrance with P. penetrans.

• Korean journal of applied entomology
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• v.21 no.3 s.52
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• pp.146-152
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• 1982

Survey on potato parasitic nematodes has been undertaken in order to find distribution of the nemic fauna. 41 soil samples were taken from potato fields in Gyeongbug, Gyeongnam and Gangweon provinces. Twenty four species belonging to 16 different genera were identified. Potato cyst nematode, Globodera rostochiensis was not found in the areas. Potato-rot nematode, Ditylenchus destructor and stem nematode, Ditylenchus dipsaci were found from several potato fields and population density high and showed damage to the crops. Root-lesion nematode, Pratylenchus minyus, Pratylenchus penetrans, Pratytenchus thornei and Pratylenchus vulnus were found and their population of these four species were high depending on the fields. Root-knot nematode, Meloidogyne hapla and Meloidogyne incognita were found. M. hapla was found only in Gangweon province and the population density was high. M. incognita was found at Milyang in Gyeongnam province. Spiral nematode, Heticotylenchus digonichus, Helicotylenchus dihystera, Helicotylenchus pseudorobustus, Rotylenchus orientalis and Rotylenchus pini were found. Aphelenchoides saprophilus, Criconemoides informis, Ditylenchus destructor, D. dipsaci, Helicotylenchus digonichus, H. dihystera, Hemicriconemoides intermedius, Meloidogyne hapla, Psilenchus hilarulus, Pratylenchus minyus, and Xiphinema americanum were first found from potato fields in Korea.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.159-163
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• 1987

In order to investigate the distribution and density of root-knot nematodes in economic crops, samples were collected from 3,226 fields of 18 economic crops. Nematodes were extracted using a modified Baermann's funnel technique. Identification of races was based on the differential host-test for Meloidogyne spp. by Tayler and Sasser. M. hapla was dominant in fields in the middle parts of Korean peninsula; M. incognita, in the southern parts, and distribution of M. javanica was limited to Jeju island and southern seaside areas. Two races of M. arenaria identified in this study were races 1 and 2. The three races identified in M. incognita were races, 1, 2 and 3. Of these races, race 1 of M. arenaria and race 3 of M. icognita were identified for the first time in Korea.

• The Plant Pathology Journal
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• v.34 no.1
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• pp.35-43
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• 2018

Root-knot nematodes (Meloidogyne spp.) are parasites that attack many field crops and orchard trees, and affect both the quantity and quality of the products. A root-colonizing bacterium, Pseudomonas chlororaphis O6, possesses beneficial traits including strong nematicidal activity. To determine the molecular mechanisms involved in the nematicidal activity of P. chlororaphis O6, we constructed two mutants; one lacking hydrogen cyanide production, and a second lacking an insecticidal toxin, FitD. Root drenching with wild-type P. chlororaphis O6 cells caused juvenile mortality in vitro and in planta. Efficacy was not altered in the fitD mutant compared to the wild-type but was reduced in both bioassays for the mutant lacking hydrogen cyanide production. The reduced number of galls on tomato plants caused by the wild-type strain was comparable to that of a standard chemical nematicide. These findings suggest that hydrogen cyanide-producing root colonizers, such as P. chlororaphis O6, could be formulated as "green" nematicides that are compatible with many crops and offer agricultural sustainability.

• Horticultural Science & Technology
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• v.32 no.2
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• pp.217-226
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• 2014

Root-knot symptoms were found on a commercial tomato cultivar carrying Mi, a resistance gene to root-knot nematodes including Meloidogyne incognita, M. arenaria, and M. javanica in 2012 at Buyeo, Chungnam Province in Korea. The isolate was identified as M. incognita based on molecular analyses using two species-specific primer sets. Pathogenicity of the isolate on one susceptible and three resistant tomato cultivars to the root-knot nematodes was tested. The nematode isolate showed strong pathogenicity on all the tested cultivars at all tested incubation temperatures. In addition, resistance degree of 33 commercial tomato cultivars, 8 susceptible and 25 resistant cultivars to root-knot nematodes, was also tested. Plants were determined as resistant when they suppressed the nematode reproduction. All the cultivars demonstrated strong susceptibility to the nematode regardless of resistance of the tomato cultivars. To our knowledge, this is the first report on the occurrence of Mi infecting M. incognita isolate in Korea. On the other hand, to construct an efficient screening method for selecting resistant breeding source to the nematode isolate, root-knot development of M. incognita on four tomato cultivars according to several conditions such as inoculum concentration, plant growth stage, and incubation period after transplant was investigated. Reproduction of the nematode on all the tested cultivars according to inoculum concentration increased in a dose-dependent manner. Except for inoculum concentration, there was no significant difference in reproduction level of the cultivars according to the other tested conditions. On the basis of the results, we suggest an efficient screening method for new resistant tomato to the nematode isolate.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.147-155
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• 2021

To investigate the incidence of plant-parasitic nematodes (PPNs) in perilla fields in Korea, 55 soil samples were collected from open fields and plastic-film house fields and were analyzed during January 2020 to October 2020. Root-lesion nematodes (RLNs), spiral nematodes, root-knot nematodes, and stunt nematodes were detected in perilla fields, and the incidences of RLNs (39%) and spiral nematodes (55%) were higher than those of other nematodes. Among PPNs, RLNs are very important species found on economic crops. The detection frequency of RLNs was increased due to continuous crop cultivation, and the frequency of fields that cultivated only one crop continuously for over 11 years was twice higher than the frequency of fields that cultivated only one crop for less than 5 years. The PPN species diversity and density were different between leaf-perilla cultivation fields and seed-perilla cultivation fields. In phylogenetic analysis of RLNs, Pratylenchus penetrans, P. vulnus, and Pratylenchoides leiocauda were identified in perilla fields. These results suggest the RLNs should be considered for establishing nematode management strategies in perilla fields in Korea.