• 식물병연구
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• 제24권1호
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• pp.33-40
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• 2018

본 연구는 무기살균제, 식물추출물, 미생물 등 우리나라에 등록된 병해관리용 유기농자재 중 19종에 대해 배검은별무늬병균과 배붉은별무늬병균을 접종하고 배 잎 조직에서의 항균활성을 확인하고자 수행하였다. 배검은별무늬병균에 대해 황, 구리 등이 함유된 유기농자재 9종 중에서 대부분은 포자발아를 완전히 억제하였고, 일부 발아한 포자의 경우에도 부착기가 전혀 형성되지 않았으나 배붉은별무늬병균에 대해서는 석회황합제, 네오보르도, 흰가리스 등에 한하여 항균활성을 보였다. 식물추출물을 함유하는 유기농자재 중 흰가루자바는 배 검은 별무늬병균의 분생포자 발아를 완전하게 억제하였으며 배 붉은별무늬병균에 대해서도 71.6% 수준으로 비교적 높은 포자발아 억제효과를 보였다. 미생물 함유 제제로써 청고탄(Streptomyces griseus)은 배검은별무늬병균에 대해 88.8%의 포자발아억제율을 보이고 부착기도 형성하지 않으며 세포간에 자재집적이 확인되지 않았다. 탑시드(Paenibacillus polymyxa)는 배검은별무늬병균과 배 붉은별무늬병균에 대해 포자발아억제율이 각각 71.0%와 90.6% 수준이며 부착기형성도 이뤄지지 않았다. 향후 직접적인 접촉으로 인하여 발생되는 보호효과뿐만 아니라 미생물 대사산물과 천연화합물이 지니고 있는 유도저항성 효과도 고려하여 포장조건에서 누적적으로 살포하면서 종합적인 항균활성을 검토할 필요가 있다.

• Mycobiology
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• 제40권2호
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• pp.111-116
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• 2012

Ten strains of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana were evaluated to find the most effective strain for optimization studies. The first criterion tested for strain selection was the mortality (> 50%) of Spodoptera litura larvae after inoculation of the fungus for 4 days. Results on several bioassays revealed that B. bassiana BNBCRC showed the most virulence on mortality S. litura larvae (80% mortality). B. bassiana BNBCRC also showed the highest germination rate (72.22%). However, its conidia yield ($7.2{\times}10^8$ conidia/mL) was lower than those of B. bassiana B 14841 ($8.3{\times}10^8$ conidia/mL) and M. anisopliae M6 ($8.2{\times}10^8$ conidia/mL). The highest accumulative radial growth was obtained from the strain B14841 (37.10 mm/day) while the strain BNBCRC showed moderate radial growth (24.40 mm/day). M. anisopliae M6 possessed the highest protease activity (145.00 mU/mL) while M. anisopliae M8 possessed the highest chitinase activity (20.00 mU/mL) during 96~144 hr cultivation. Amongst these criteria, selection based on virulence and germination rate lead to the selection of B. bassiana BNBCRC. B. bassiana B14841 would be selected if based on growth rate while M. anisopliae M6 and M8 possessed the highest enzyme activities.

• 한국작물학회지
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• 제63권1호
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• pp.57-63
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• 2018

The effects of endophytic microbial inoculation and temperature on the phenolic content of tartary buckwheat (TP) sprouts were investigated. TP seeds were inoculated with Herbaspirillum spp. at concentrations (%v/v) of 0 (control), 10, 20, and 40% at 20, 25, and $30^{\circ}C$ in a growth chamber for seven days. It was observed that the phenolic content (PC) including flavonoid, rutin, and tanin increased with an increase in inoculant rate at $20^{\circ}C$, whereas the PC content increased with an increase in temperature regardless of the inoculant rate. Therefore, it is suggested that increasing the inoculant rate is effective at achieving higher phenolic contents when plants are grown at lower temperatures.

• 식물병연구
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• 제28권4호
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• pp.245-247
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• 2022

In August 2021, we surveyed diseases of wild vegetables grown in Taebaek, Gangwon Province, Korea. During the disease survey, we observed severe damping-off symptoms in young edible aster (Aster scaber) plants in a vinyl greenhouse investigated. The incidence of the disease in the plants ranged from 5% to 20%. Diseased plants of edible aster were collected from the vinyl greenhouse, and fungi were isolated from petiole lesions of the diseased plants. Rhizoctonia sp. was consistently isolated from the petiole lesions. We examined morphological characteristics and anastomosis groups of nine Rhizoctonia sp. isolates obtained from the petiole lesions. The examination results revealed that all the isolates corresponded to Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for their pathogenicity on edible aster plants by artificial inoculation. Inoculation tests showed that the tested isolates caused damping-off symptoms on the inoculated plants. The induced symptoms were similar to those observed in the vinyl greenhouse investigated. Damping-off of edible aster caused by R. solani AG-4 is first reported in this study.

• 식물병연구
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• 제29권4호
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• pp.377-383
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• 2023

In 2020 and 2021, we surveyed diseases of three-leaf ladybell (Adenophora triphylla) plants grown in fields at two locations in Korea. During the disease surveys, severe leaf rot symptoms were observed on the young plants in Hongseong, and stem rot symptoms on the adult plants in Cheolwon. The incidence of leaf rot was 5-60%, and that of stem rot 1-10%. We obtained 6 fungal isolates each from the leaf rot lesions and the stem rot lesions. All the isolates were morphologically identified as Rhizoctonia solani. Anastomosis test and investigation of cultural features of the fungal isolates revealed that the isolates from the leaf rot lesions corresponded to R. solani AG-1(IB), and those from the stem rot lesions to R. solani AG-2-2(IIIB). Two isolates each of R. solani AG-1(IB) and AG-2-2(IIIB) were used for DNA sequence analysis and pathogenicity test to three-leaf ladybell plants through artificial inoculation. The anastomosis groups and cultural types of the R. solani isolates were confirmed by the sequence analysis. The pathogenicity tests revealed that the isolates of R. solani AG-1(IB) caused only leaf rot symptoms on the inoculated plants, and those of R. solani AG-2-2(IIIB) leaf rot and stem rot symptoms. The induced symptoms were similar to those observed in the fields investigated. Leaf and stem rot of three-leaf ladybell caused by the two anastomosis groups and cultural types of R. solani is first reported in this study.

• 한국균학회지
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• 제48권4호
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• pp.519-521
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• 2020

Damping-off symptoms were frequently observed on young plants of Indian lettuce (Lactuca indica) grown in a farmer's vinyl greenhouse located in Goseong, Gangwon province of Korea during a disease survey in June 2019. The incidence of diseased plants in the vinyl greenhouse investigated was 30-50%. Four isolates of Rhizoctonia sp. were obtained from the diseased plants and identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on Indian lettuce by artificial inoculation. All the tested isolates induced damping-off symptoms on the inoculated plants. The symptoms were similar to those observed in plants from the farmer's vinyl greenhouse investigated. This is the first report of R. solani AG-4 causing damping-off in Indian lettuce.

• 식물병연구
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• 제27권1호
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• pp.45-47
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• 2021

Damping-off symptoms were frequently observed on young plants of coastal hogfennel (Peucedanum japonicum) grown in a farmer's vinyl greenhouse located in Goseong, Gangwon Province, Korea during a disease survey in June 2019. Incidence of the diseased plants was 50-70% in the vinyl greenhouse investigated during the disease survey. Eight isolates of Rhizoctonia sp. were obtained from the diseased plants. All the isolates were identified as Rhizoctonia solani AG-4 based on the morphological characteristics and anastomosis test. Three isolates of R. solani AG-4 were tested for pathogenicity on coastal hogfennel by artificial inoculation. All the tested isolates induced damping-off symptoms on the inoculated plants. The symptoms were similar to those observed in the farmer's vinyl greenhouse investigated. This is the first report of R. solani AG-4 causing damping-off in coastal hogfennel.

• The Plant Pathology Journal
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• 제39권3호
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• pp.255-264
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• 2023

Sweet potato symptomless virus 1 (SPSMV-1) is a single-stranded circular DNA virus, belonging to the genus Mastrevirus (family Geminiviridae) that was first identified on sweet potato plants in South Korea in 2012. Although SPSMV-1 does not induce distinct symptoms in sweet potato plants, its co-infection with different sweet potato viruses is highly prevalent, and thus threatens sweet potato production in South Korea. In this study, the complete genome sequence of a Korean isolate of SPSMV-1 was obtained by Sanger sequencing of polymerase chain reaction (PCR) amplicons from sweet potato plants collected in the field (Suwon). An infectious clone of SPSMV-1 (1.1-mer) was constructed, cloned into the plant expression vector pCAMBIA1303, and agro-inoculated into Nicotiana benthamiana using three Agrobacterium tumefaciens strains (GV3101, LBA4404, and EHA105). Although no visual differences were observed between the mock and infected groups, SPSMV-1 accumulation was detected in the roots, stems, and newly produced leaves through PCR. The A. tumefaciens strain LBA4404 was the most effective at transferring the SPSMV-1 genome to N. benthamiana. We confirmed the viral replication in N. benthamiana samples through strand-specific amplification using virion-sense- and complementary-sense-specific primer sets.

• 식물병연구
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• 제14권3호
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• pp.182-186
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• 2008

최근 벼 유기재배에서 식물병 방제를 위한 친환경농자재가 없는 것이 주요한 제한요인으로 제기되고 있다. 식물병 방제를 위해 보르도액은 효과적인 예방 농자재로 사용되어져 왔다. 본 연구에서는 석회보르도액의 벼 잎도열병 방제효과를 조사하였다. 온실검정결과 6-6식 석회보르도액 100배액을 발병초에 살포한 결과 70.8%의 방제효과를 나타냈다. 포장검정에서는 4-8식과 6-6식 석회보르도액을 살포한 결과 잎도열병에 대한 방제효과가 73.6%와 71%를 나타냈다. 각각 조제한 석회보르도액의 30배와 50배 처리농도에서는 약해가 발생하였으나, 200배액 살포농도에서는 약해가 나타나지 않았다. 따라서 유기재배 및 무농약 재배포장에서 벼 잎도열병 방제를 위한 효과적인 친환경농자재로서 석회보르도액이 활용될 수 있을 것으로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제23권4호
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• pp.489-498
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• 2013

A new Bacillus strain degrading starch, named Bacillus sp. UEB-S, was isolated from a southern Tunisian area. Amylase production using solid-state fermentation on millet, an inexpensive and available agro-resource, was investigated. Response surface methodology was applied to establish the relationship between enzyme production and four variables: inoculum size, moisture-to-millet ratio, temperature, and fermentation duration. The maximum enzyme activity recovered was 680 U/g of dry substrate when using $1.38{\times}10^9$ CFU/g as inoculation level, 5.6:1 (ml/g) as moisture ratio (86%), for 4 days of cultivation at $37^{\circ}C$, which was in perfect agreement with the predicted model value. Amylase was purified by Q-Sepharose anion-exchange and Sephacryl S-200 gel filtration chromatography with a 14-fold increase in specific activity. Its molecular mass was estimated at 130 kDa. The enzyme showed maximal activity at pH 5 and $70^{\circ}C$, and efficiently hydrolyzed starch to yield glucose and maltose as end products. The enzyme proved its efficiency for digesting raw cereal below gelatinization temperature and, hence, its potentiality to be used in industrial processes.