• Research in Plant Disease
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• v.9 no.1
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• pp.36-38
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• 2003

Stem blight of brunfelsia (Brunfelsia calycina) caused by Fusarium oxysporum was found in greenhouse around Sungnam area, Kyunggi province, Korea in September 2001. The initial infection appeared as a slight wilting of the foliage, turned yellow from the lower leaves. The yellowing leaves were falled, resulting in blight of stem and eventual death of the entire plant. The vascular tissue of a diseased plants became dark brown and browning of the vascular system was a characteristic of the disease and the pith remained healthy, Isolates obtained from the lesions of the diseased plant were identified as F. oxysporum, based on the morphological characteristics of conidia. Symptom by artificial inoculation was same to the symptom of naturally infected plants. This is the first report demonstrating the stem blight on a brunfelsia caused by F. oxysporum in Korea, and we proposed to name this disease "stem blight of brunfelsia".

• Journal of the Korean Society of International Agriculture
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• v.23 no.5
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• pp.503-506
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• 2011

In order to analyze the resistant gene to Xanthomonas oryzae pv. oryzae in Korean native rices. Six Korean native rice varieties were crossed with IR-BB 101 contains Xa1 resistant gene and inoculated Japanese isolates IA(T7174). Cheonggunbyeo has Xa1 resistant gene only, and Yukseongjaerae, Agukdo, Heukpi and Icheon7ilchal have Xa1 and another one dominant gene. Ginggaragshare has Xa1 and another two dominant genes and two of those genes concerned complementary interaction against Japanese isolates IA(T7174).

• Weed & Turfgrass Science
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• v.2 no.1
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• pp.88-94
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• 2013

Brown patch caused by Rhizoctonia solani AG-1 IB occurred on Kentucky bluegrass during late May through early October 2010 at golf course in Gyeongbuk Province, Korea. Disease symptoms on the turfgrass for spring season were leaf blights dying from the leaf tip, which appeared patches of brown color in the field. However, it appeared patches of dark brown color or gray brown color in fall. The fungus (B-7 isolate) of brown patch was isolated from the diseased leaf tissue and cultured on potato-dextrose agar (PDA) for identification. The young hyphae had acute angular branching and few septa and mature hyphal branches showed about 90-degree angles and development of monilioid cells, which were morphologically identical to Rhizoctonia solani AG-1 IB reported previously. DNA sequences of ribosomal RNA gene (internal transcribed spacer) of the fungus were homologous with similarity of 99% to those of Rhizoctonia solani AG-1 IB isolates in GenBank database, confirming the identity of the causal agent of the disease. Pathogenicity of the fungus was also confirmed on the creeping bentgrass and Kentucky bluegrass by Koch's postulates. This is the first report of brown patch on Kentucky bluegrass caused by Rhizoctonia solani AG-1 IB in Korea.

• Journal of Life Science
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• v.22 no.2
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• pp.177-183
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• 2012

Bacterial wilt (brown rot) caused by Ralstonia solanacearum (Rs) is one of the most devastating bacterial plant diseases in potatoes. To isolate bacterial wilt disease resistance-related genes from the potato, the StACRE (HM749652) gene was isolated and a sequenced search was performed using functional orthologs of Solanaceae from potatoes. StACRE is homologous to the tobacco NtACRE 132 protein and belongs to the ATL family involved in ubiquitination. To analyze the expression pattern of this gene, RT-PCR was performed with potato treated with salicylic acid (SA) and Rs (KACC 10722). StACRE was strongly induced 3 hours after treatment with SA and 12 hours after infection with Rs. To investigate its biological functions in the potato, we constructed a vector for overexpression in the potato by the Gateway system, and then generated transgenic potato plants. The gene expression of transgenic potato was analyzed by northern blot analysis. In the results of disease resistance assay in relation to bacterial wilt, StACRE overexpressed transgenic potato plants were shown to have more resistance than wild-type potato.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.419-423
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• 2003

Bacterial blight caused by Xantomonas oryzae pv. oryzae is one of the most serious diseases of rice especially in southern area of Korea. Three races, $\textrm{K}_1$, $\textrm{K}_2$ and $\textrm{K}_3$, are the most dominant species. lo improve rice breeding efficiency using marker assisted selection, some RFLP markers were surveyed for polymorphism between resistant and susceptible to $\textrm{K}_1$ and $\textrm{K}_3$. And, 127 doubled-haploid (DH) lines derived from Milyang121/HRl1650-1-4-2 and 131 DH lines derived from Milyang123/HR10624-AC5 were evaluated to bacterial blight ($\textrm{K}_1$ and $\textrm{K}_3$). Milyang121 and HR10624-AC5 have Xa-1, resistant to $\textrm{K}_1$ race, and Milyang123 has Xa-3, resistant to $\textrm{K}_1$ and $\textrm{K}_3$ race. Three markers, RZ590, RZ536 and RG303, showing polymorphism between parents and resistance gene, Xa-1 and Xa-3, were analysed in the two combinations of DH lines. The segregation pattern of resistant DH population of Milyang123/HR10624-AC5 to susceptible showed 3:1 and 1:1 in $\textrm{K}_1$ and $\textrm{K}_3$ race. In three RFLP markers, RZ590 was linked to Xa-1 on chromosome 4, and RZ536 and RG303 were linked to Xa-3 on chromosome 11. The map distance between Xa-1 and RZ590 was 3.1cM on chromosome 4, and Xa-3 and RZ536/RG303 were 7.6/16.0cM on chromosome 11, respectively. The results of RFLP mapping will be useful for the selection and pyramiding of bacterial blight resistant genes.

• Research in Plant Disease
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• v.16 no.3
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• pp.224-231
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• 2010

Xanthomonas oryzae pv. oryzae, causal agent of bacterial leaf blight (BLB) of rice, had been collected and identified using Biolog and fatty acid analysis. Epidemics of BLB had been occurred all the times at several rice cultivating areas in Korea in 1999-2004. Most X. oryzae pv. oryzae isolated in 1999 and 2002 belonged to Korean race K1, but more than 50% of the pathogen isolated in 2003 belonged to Korean race K3. Especially, most pathogens isolated in Jeonnam and Joenbuk provinces belonged to Korean race K3. Inoculation test of near isogenic lines (NIL) of rice carrying single resistance genes against BLB showed that many isolates belonging to Korean race 1 reacted differently to diverse resistant monogenic lines of rice. Southern blot analysis also showed that the bacterial pathogens belonged to the same race had different numbers of avirulence genes. This results suggested that each Korean race type may respond to many resistance genes of rice. All the K3 races isolated in Jeonnam and Joenbuk provinces were able to cause disease on Xa3 monogenic lines of rice. Since most rice cultivars cultivated in Jeonnam and Jeonbuk were carrying Xa3 resistance genes, the bacterial pathogens isolated in Jeonnam and Jeonbuk were likely to develop to adapt to Xa3 resistance gene. Together with avirulence gene patterns of the bacterial isolates and the results of disease reaction of monogenic lines of rice to them, Korean X. oryzae pv. oryzae was classified into 19 pathotypes. This newly classified pathotypes should help the breeding of new resistance rice cultivars in Korea.

• Research in Plant Disease
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• v.23 no.3
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• pp.283-287
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• 2017

The twig blight of mulberry caused by Fusarium lateritium occurs mainly in Buan area, which is the main area of mulberry. The initial symptom on twigs showed dark edge blight and dark orange tiny particles on the spot, and it was withered and died. In the case of mulberry twig blight, the difference in the degree of occurrence between the years is intense, and an average of 2.7% occurred in Buan in 2013, but in 2014, it was difficult to search for the generated fields. In order to find the cause of the difference in the incidence of mulberry twig blight, we investigated and analyzed the weather conditions during cultivation and as a result, the occurrence of the disease increased under the condition that the temperature of the spring was lower and the number of days passing below the winter freezing point increased. In addition, it was analyzed that the occurrence of the next year increases when the rainfall is high and the number of sunshine is low after removing the harvested branches. Therefore, in the event that weather conditions causing twig blight diseases have elapsed, it is necessary to prevent the disease by spraying the registered applied fungicide prophylactically.

• Microbiology and Biotechnology Letters
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• v.32 no.3
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• pp.256-264
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• 2004

A new primer set was developed for the detection and identification of Xanthomonas oryzae pv. oryzae, the bacterial leaf blight (BLB) pathogen in rice plant. The nucleotide sequence of hpaA gene was determined from X. o. pv. oryzae str. KACC10331, and the sequence information was used to design primers for the application of the polymerase chain reaction (PCR). The nucleotide sequence of hpaA from X. o. pv. oryzae str. KACC 10331 was aligned with those of X. campestris pv. vesicatoria, X. campestris pv. campestris, X. axonopodis pv. citri, and X. axonopodis pv. glycines. Based on these results, a primer set(XOF and XOR) was designed for the specific detection of hpaA in X. o. pv. oryzae. The length of PCR products amplified using the primer set was 534-bp. The PCR product was detected from only X. o. pv. oryzae among other Xanthomonas strains and reference bacteria. This product was used to confirm the conservation of hpaA among Xanthomonas strains by Southern-blotting. Furthermore, PCR amplification with XOF and XOR was used to detect the pathogen in an artificially infected leaf. The sensitivity of PCR detection in the pure culture suspension was also determined. This PCR-based detection methods will be a useful method for the detection and identification of X. o. pv. oryzae as well as disease forecasting.

• Asian Journal of Turfgrass Science
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• v.26 no.2
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• pp.96-101
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• 2012

Dollar spot caused by Sclerotinia homoeocarpa F.T. Benn. is a common and economically important turfgrass disease in South Korea. Fungicides were evaluated for control of dollar spot in creeping bentgrass golf course putting green. Commercial formulations of propiconazole, thiophanate-methyl, chlorothalonil, trifloxystrobin and boscalid were applied to plots of creeping bentgrass, each of the latter four fungicides was tank mixed with propiconazole at the same rates, and applied as treatments. The dollar spot severity in the nontreated plots of field A and B progressed toward peak diseases of 18.3 and 66.7% from 10 or 15 days after inoculation, respectively. Significant differences were detected among control values of the fungicides. Dollar spot control provided by boscalid was significantly greater than the other fungicides which showed low control values in a higher disease condition. No synergistic interactions, except propiconazole + thiophanate-methyl treated plot, were detected under a lower disease pressure. However, under a higher disease pressure, synergism was observed at all fungicide combinations, except a propiconazole and boscalid tank mixture. These data suggest turfgrass managers in golf course can take advantage of fungicide synergism to control dollar spot using the products and rates in this study.

• Research in Plant Disease
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• v.13 no.3
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• pp.152-156
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• 2007

Incidences of leaf blight of lily cultivars Raizan and Casa Blanca in the open field cultivation were 50% and 45.4%, respectively, while those in the green house cultivation were significantly reduced to 1.5% and 1.9%, respectively, In the green house, the incidences of the disease in sprinkler watering cultivation were $14.5{\sim}16.5%$, while those in drip watering cultivation were only $1.5{\sim}2%$. Incidence of the disease was severe in the field where the lily was cultivated successively for 2 to 3 years. Isolation frequencies of B. elliptica from overwintered plant debrises such as leaves, stems, capsules, and bulbs were 43.3%, 46.7%, 60% and 0%, respectively, while those of B. cinerea were 10.3%, 0%, 3.3% and 0%, respectively, Incidence of leaf blight in the field where diseased plant debris was cleaned was 7.3%, while that in the field where diseased plant debris was not cleaned was 56.5%. Incidences of the disease in the field where coverages of soil surface with black vinyl, bark or rice straw were used were 6.6%, 8.2% and 11.3%, respectively, while that in the field where the coverage was not used was 21.3%.