• Parasites, Hosts and Diseases
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• 제59권3호
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• pp.319-324
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• 2021

Incidence of tsutsugamushi disease (scrub typhus) caused by Orientia tsutsugamushi, is steadily increasing. It is a mite-borne disease transmitted by chigger mites. In this study, the chigger mites were collected from field small mammals in Hwaseong-si (city), Gyeonggi-do (province), Korea, 2019 and 2020. The field small mammals captured were 56 Apodemus agrarius (94.9%) and 3 Crocidura lasiura (5.1%). A total of 7,531 chigger mites were collected from the captured small mammals. Using PCR test, 153 chigger mite pools were examined and 17 pools were reported positive for O. tsutsugamushi. The O. tsutsugamushi were identified to 5 strains; Jecheon strain was most prevalent, followed by Boryong strain. The other strains were OI011, Taguchi, and Shimokoshi. Collectively, these results provide essential regional information on mite-borne tsutsugamushi disease in the Hwaseong-si, and further contribute to bring awareness and rapid diagnosis for the tsutsugamushi disease.

• The Plant Pathology Journal
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• 제39권4호
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• pp.374-383
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• 2023

Capsicum annuum (CA) is grown outdoors across fields in Jeollabuk-do, South Korea. The weeds surrounding these fields were investigated regarding the infection of 11 viruses infecting CA during the year 2014-2018. In the reverse transcription polymerase chain reaction diagnosis, 546 out of 821 CA samples (66.5%) were infected by nine viruses, and 190 out of 918 weed samples (20.7%) were infected by eight viruses. Correlation analysis of the mutual influence of the viruses infecting CA and weeds during these 5 years showed that five viruses had significant positive correlations with the infection in both CA and weeds. Over the study period, the weeds infected by cucumber mosaic virus (CMV) in the previous year were positively correlated with the incidence of CMV infection in CA in the current year, although the correlation was lower for tomato spotted wilt virus (TSWV) compared to CMV. The CMV infection percent was 14.0% in summer annuals, 11.4% in perennials, and 7.8% in winter annuals. However, considering the overwintering period without CA, the infection percent was 5.2% higher in winter annuals and perennials than that in summer annuals, indicating that winter annual and perennial weeds served as the main habitats for insect vectors. The TSWV infection percent in weeds was 10.4% in summer annuals, 6.4% in winter annuals, and 6.2% in perennials. The weeds surrounding CA fields, acting as the intermediate hosts, were found to be the potent sources of infection, influencing the spread and diversity of CA-infecting viruses. The results of this study can contribute to prevent viral infection in agricultural fields.

• Journal of Plant Biotechnology
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• 제35권2호
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• pp.101-108
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• 2008

아그로박테리움을 이용한 형질전환은 대다수의 쌍자엽과 몇몇 단자엽 식물의 게놈내로 외래유전자를 도입하는 성공적인 방법이다. 해충저항성 CryIAc 유전자가 도입된 배추형 질전환체를 아그로박테리움 형질전환법을 통해 얻은 후, 도입유전자의 수를 Southern 분석을 통하여 확인하였다. 배추형질전환체 46개 중에서 29개는 1 copy의 CryIAc 유전자가 도입된 것으로 확인되었다. 식물체의 게놈내로 T-DNA 결합에 관한 정보를 얻기 위해서 LB 인접서열을 genome walking PCR 방법을 통하여 분석하였다. 46개의 배추형질전환체중에서 37개는 운반체의 backbone 염기서열을 지니는 것으로 확인되었다. 이러한 결과는 도입 운반체의 LB 지점에서 제대로 종결이 이루어지지 않아서 운반체의 backbone 염기서열이 운반된 것으로 보여진다. 운반체의 backbone 염기서열이 도입되지 않은 9개체의 배추형질전환체를 LB 인접서열을 분석한 결과, 모든 LB 부위는 절단부위가 보존되지 않았고, 절단부위에서 36bp까지도 결실이 확인되었다.

• 한국응용곤충학회지
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• 제52권1호
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• pp.23-27
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• 2013

담배가루이가 매개하는 토마토황화잎말림병(TYLCV) 예방을 목적으로 해충의 유입을 원천적으로 차단할 수 있는 방충망 설치에 대한 연구가 수행되었다. 담배가루이가 60메쉬망을 통과는 할 수 있지만, 83메쉬 이상의 방충망으로 완전히 차단할 수 있었다. 담배가루이의 온실 내 유입을 차단하기 위한 3연동 온실($21.0{\times}18.3m$)에 60메쉬 망실, $5.65(W){\times}2.05(H){\times}18.45(L)(m)$을 별도로 설치하였다. 60메쉬 망실 내에서 담배가루이 산란과 아메리카잎굴파리 가해흔적이 출입문 쪽에 국부적으로 몇몇 발견되었으나, 토마토황화잎말림병에 걸린 토마토는 없었다. 토마토의 초장, 엽장, 엽폭, 화방수, 당도 조사결과 망실유무에 따른 처리구간의 차이는 없는 것으로 나타났고, 수량에서도 유의성 있는 차이를 발견할 수 없었다. 실용적인 관점에서 방충망의 설치는 유리온실이나 장기간 사용가능한 비닐온실 등의 측창과 천창 및 출입구에 설치할 경우 유망할 것으로 생각되었다.

• 한국산림과학회지
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• 제98권6호
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• pp.696-702
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• 2009

본 연구는 충매화인 백합나무의 구조적 생리적 특성을 활용하여 인공교배 시 교배봉투 설치 과정의 생략이 가능한지 여부를 판단하기 위해 수행되었다. 이를 위해 1) 자연 상태(open-pollination)의 비교구, 2) 생식기관(꽃잎, 수술)을 제거하지 않고 교배봉투만 설치(self-pollination), 3) 생식기관만 제거하고 방치, 4) 생식기관 제거 및 인공수분을 실시 후 교배봉투 설치, 5) 생식기관 제거 및 인공수분 실시 후 교배봉투를 씌우지 않는 5 가지의 교배처리를 하였다. 시험결과, 생식기관을 제거하지 않고 교배봉투만 설치한 2번 처리구에서는 충실종자가 전혀 만들어지지 않아 자연 상태에서 자가수분에 의해 종자가 결실될 확률은 매우 낮은 것으로 보인다. 생식기관만 제거하고 교배봉투를 씌우지 않은 3번 처리구의 충실종자 결실률은 0.2%로 통상적인 대규모 인공교배 시의 발생하는 오차수준 보다 매우 낮은 미미한 수준이었다. 생식기관을 제거하고 인공수분을 실시한 후 교배봉투를 씌운 4번 처리구와 씌우지 않은 5번 처리구 종자 충실률은 각각 27.9%와 24.0%로 나타나 인공수분 후 교배봉투를 씌우지 않아도 외부 화분의 유입에 의한 종자 결실률의 증가는 없는 것으로 보인다. 이상의 결과를 종합해 보면 백합나무에서는 대규모 인공교배 시 인공수분 후 교배봉투를 씌우는 과정을 생략해도 큰 무리가 없을 것으로 생각된다.

• Parasites, Hosts and Diseases
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• 제58권5호
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• pp.551-558
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• 2020

The flaviviruses are small single-stranded RNA viruses that are typically transmitted by mosquitoes or tick vectors and are etiological agents of acute zoonotic infections. The viruses are found around the world and account for significant cases of human diseases. We investigated population of culicine mosquitoes in central region of Korean Peninsula, Incheon Metropolitan City and Hwaseong-si. Aedes vexans nipponii was the most frequently collected mosquitoes (56.5%), followed by Ochlerotatus dorsalis (23.6%), Anopheles spp. (10.9%), and Culex pipiens complex (5.9%). In rural regions of Hwaseong, Aedes vexans nipponii was the highest population (62.9%), followed by Ochlerotatus dorsalis (23.9%) and Anopheles spp. (12.0%). In another rural region of Incheon (habitat of migratory birds), Culex pipiens complex was the highest population (31.4%), followed by Ochlerotatus dorsalis (30.5%), and Aedes vexans vexans (27.5%). Culex pipiens complex was the predominant species in the urban region (84.7%). Culicine mosquitoes were identified at the species level, pooled up to 30 mosquitoes each, and tested for flaviviral RNA using the SYBR Green-based RT-PCR and confirmed by cDNA sequencing. Three of the assayed 2,683 pools (989 pools without Anopheles spp.) were positive for Culex flaviviruses, an insect-specific virus, from Culex pipiens pallens collected at the habitats for migratory birds in Incheon. The maximum likelihood estimation (the estimated number) for Culex pipiens pallens positive for Culex flavivirus was 25. Although viruses responsible for mosquito-borne diseases were not identified, we encourage intensified monitoring and long-term surveillance of both vector and viruses in the interest of global public health.

• International Journal of Industrial Entomology and Biomaterials
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• 제11권2호
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• pp.125-127
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• 2005

In order to improve the transformation efficiency of the Bacillus thuringiensis (Bt)-Escherichia coli (E. coli) shuttle vector, pHT3101, we intended to minimize replication origin of Bt in pHT3101. For this, two modified shuttle vectors, pHT1K and pHT261, in which 2.9 kb of replication origin of Bt were shortened to 1 kb and 261 bp, respectively as previously reported. Whereas the pHT1K could efficiently transform Bt into the antibiotic resistant, no transformants were obtained with pHT261. Furthermore, pHT1K showed higher transformation efficiency compared to that of parent vector, pHT3101. Therefore, pHT1K might be a very useful Bt-E. coli shuttle vector carrying minimal replication origin of Bt.

• The Plant Pathology Journal
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• 제34권5호
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• pp.356-366
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• 2018

The red flour beetle, Tribolium castaneum, is one of the most common and economically important pests of stored cereal products worldwide. Furthermore, these beetles can act as vectors for several fungal post-harvest diseases. In this study, we collected T. castaneum from 49 rice processing complexes (RPCs) nationwide during 2016-2017 and identified contaminating fungal species on the surface of the beetles. Five beetles from each region were placed on potato dextrose agar media or Fusarium selection media after wet processing with 100% relative humidity at $27^{\circ}C$ for one week. A total of 142 fungal isolates were thus collected. By sequence analysis of the internal transcribed spacer region, 23 fungal genera including one unidentified taxon were found to be associated with T. castaneum. The genus Aspergillus spp. (28.9%) was the most frequently present, followed by Cladosporium spp. (12.0%), Hyphopichia burtonii (9.2%), Penicillium spp. (8.5%), Mucor spp. (6.3%), Rhizopus spp. (5.6%), Cephaliophora spp. (3.5%), Alternaria alternata (2.8%) and Monascus sp. (2.8%). Less commonly identified were genera Fusarium, Nigrospora, Beauveria, Chaetomium, Coprinellus, Irpex, Lichtheimia, Trichoderma, Byssochlamys, Cochliobolus, Cunninghamella, Mortierella, Polyporales, Rhizomucor and Talaromyces. Among the isolates, two known mycotoxin-producing fungi, Aspergillus flavus and Fusarium spp. were also identified. This result is consistent with previous studies that surveyed fungal and mycotoxin contamination in rice from RPCs. Our study indicates that the storage pest, T. castaneum, would play an important role in spreading fungal contaminants and consequently increasing mycotoxin contamination in stored rice.

• The Plant Pathology Journal
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• 제38권4호
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• pp.287-295
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• 2022

Citrus tristeza virus (CTV) is efficiently transmitted in a semi-persistent manner by the brown citrus aphid (Toxoptera citricida (Kirkaldy)). Currently, the most sensitive method for detecting plant viruses in insect vectors is reverse-transcription quantitative polymerase chain reaction (RT-qPCR). In this study, the elongation factor-1 alpha (EF-1α) gene and acidic p0 ribosomal protein (RPAP0) gene were confirmed to be suitable reference genes for RT-qPCR normalization in viruliferous T. citricida aphids using the geNorm, NormFinder, and BestKeeper tools. Then the relative CTV titer in aphids (T. citricida) at different post-acquisition feeding times on healthy plants was quantified by RT-qPCR using EF-1α and RPAP0 as reference genes. The relative CTV titer retained in the aphids gradually decreased with increasing feeding time. During the first 0.5 h of feeding time on healthy plants, the remaining CTV titer in aphids showed about 80% rapid loss for the highly transmissible isolate CT11A and 40% loss for the poorly transmissible isolate CTLJ. The relative CTV titer in aphids during more than 12 h post-acquisition times for CT11A was significantly lower than at the other feeding times, which is similar to the trend found for CTLJ. To our knowledge, this is the first report about the relative titer variation of CTV remaining in T. citricida at different post-acquisition feeding times on healthy plants.

• 한국응용곤충학회지
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• 제55권2호
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• pp.177-188
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• 2016

알파 프로테박테리아(${\alpha}-proteobacterium$)인 볼바키아(Wolbachia) 세균은 절지동물 세포내의 중요한 공생균 중의 하나이다. 그람 음성 세균인 이 공생균은 기주동물의 여러 생물적 과정에 관여하고 있으며, 현재 생물적 방제 수단으로 주목 받고 있다. 볼바키아는 기주 세포의 세포질에 서식하는 세균인데 암컷을 통하여 세대간 전염된다. 볼파키아의 감염 개체 밀도를 높이기 위해 기주의 생식방식을 조작하는 다양한 전략을 발달시켰다. 볼바키아 유전자형 계통은 볼바키아 표면 단백질(WSP)의 고변이영역 아미노산 서열과 복합좌위 서열 타이핑(Multilocus sequence typing, MLST)으로 결정된다. 상이한 유전계통 판별은 wsp, 16S rRNA, ftsZ, gltA, groEL 등 유전자 분자표지를 이용하게 된다.. 이 계통 볼바키아 세균과 그들의 우월한 표현형이 농업해충과 인간의 질병매개 곤충에 대한 방제 프로그램에서 이용 가능성이 고려되고 있다. 볼바키아 표현형들은 세포질불일치(cytoplasmic incompatibility, CI), 단성생식 유도(parthenogenesis induction, PI), 여성화(feminization, F), 수컷치사(male killing, MK) 등을 유발하는 것으로 알려져 있다. 기타 볼바키아 세균의 농업과 위생곤충 방제 프로그램에서 응용 방안을 고찰하였다.