• Current Research on Agriculture and Life Sciences
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• 제32권3호
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• pp.111-117
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• 2014

고추 역병은 그 병원균의 토양전염성 때문에 약제에 의한 방제효과가 낮아 저항성 품종의 개발이 기대되어 왔다. 고추 역병에는 CM334, AC2258, PI201234 등 다수의 저항성 유전자원이 보고되었으며, 이들의 저항성의 유전에 관한 연구로 진행되었다. 그러나 저항성의 유전양식은 실험에 사용한 재료와 연구자에 따라 1개, 2개, 혹은 3개 이상의 유전자, 다수의 유전자에 의한 양적 유전 등 다양하였다. 최근에는 분자적 방법으로 양적형질유전자좌(QTL)를 구명하는 연구가 보고되고 있으며, 분자표지를 이용한 선발 기술도 이미 육종 현장에서 활용되고 있다. 최근 저항성 품종이 다수 출시됨에 따라 새로운 병원형(pathotype), 즉, 레이스(race)의 출현에 관심이 높아지면서 이에 대한 연구가 보고되고 있다. 모두 품종과 병원균주간에 특이적 변이가 있으며, 이를 토대로 몇 개의 병원형(race)으로 분류할 수 있었다. 그러나 판별품종이 통일되지 않았고 시험에 사용한 품종들의 저항성 유전자의 조성도 달라 세계적으로 통일된 레이스분류체계는 아직 없는 실정이다. 이러한 배경에서 보다 안정된 저항성 품종의 육성을 위해서는 한 가지 저항성 재료보다는 다수의 저항성 유전자원에서 저항성을 도입하고, 육성과정에 육성품종의 보급 대상지역의 여러 균주를 사용하여 선발하는 것이 필요할 것이다.

• 한국응용곤충학회지
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• 제22권2호
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• pp.52-66
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• 1983

The brown planthopper, N. lugens (Stal), has become a serious pest of rice in tropical Asia during the last decade. At high pest density, its feeding damage causes 'hopperburn' or complete wilting and drying of the rice plant. It also transmits grassy and ragged stunt virus diseases. The estimated losses caused by the pest in tropical Asia exceed $US\$300$ millions. While cultivation of resistant rice varieties has proved to be highly effective against the pest, their long-term stability is threatened because of the evolution of prolific biotypes which can destroy these varieties. At present, identification of biotypes is based principally on the differential reactions of host rice varieties to the pest and on host-mediated behavioral and physiological responses of the pest. Recent findings of morphological differences in adult rostrum, legs, and antennae, body parts that possess receptors for host plant location and discrimination, and cytological differences in N. lugens populations maintained as stock cultures strongly complement other biotype studies. So far, three N. lugens biotypes have been identified in the Philippines. Biotype I can survive on and damage varieties that do not carry and genes for resistance, while Biotype 2 survives on resistant varieties carrying Bph 1 gene and Biotype 3 on varieties carrying gene bph 2. However, none of these biotypes can survive on varieties with genes Bph 3 or bph 4. Several varieties which are resistant in the Philippines are susceptible in India and Sri Lanka as the South Asian biotypes of N. lugens are more virulent than Southeast Asian biotypes. To monitor the pest biotypes in different geographical regions and to identify new sources of resistance, an International Brown Planthopper Nursery has been established in many cooperating countries. The evolution of biotypes is an exceedingly complex process which is governed by the interactions of genetic and biological factors of the pest populations and the genetic makeup of the cultivated varieties. While the strategy for sequential release of varieties with major resistance genes has been fairly successful so far, the monegenic resistance of these varieties makes them vulnerable to the development of the pest biotypes. Therefore, present breeding endeavors envisage utilizing both major and minor resistance genes for effective control of the pest.

• 원예과학기술지
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• 제31권5호
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• pp.626-632
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• 2013

무 시들음병에 대한 저항성 검정 체계를 확립하기 위하여 실험하는 과정에서 병원균인 Fusarium oxysporum f. sp. raphani가 무 유묘에 독성(phytotoxicity)을 일으키는 독소(phytotoxin)를 생산한다는 것을 발견했다. F. oxysporum f. sp. raphani KR1 균주는 여러 배지 중 malt extract broth 배지에서 배양하였을 때 그리고 $25^{\circ}C$에서 14일 동안 150rpm으로 진탕배양하였을 때 가장 많은 독소를 생산하였다. 무에 대한 독성 반응을 이용하여 F. oxysporum f. sp. raphani의 배양액으로부터 phytotoxin을 분리하였다. 그리고 Mass와 NMR Spectroscopy 분석을 통하여 이 화합물은 fusaric acid로 동정되었다. 독소의 역할을 규명하기 위하여 fusaric acid를 무, 양배추, 브로콜리 등 F. oxysporum f. sp. raphani의 기주 및 비기주 배추과 작물에 대한 독소 활성을 조사하였다. Fusaric aicd는 무 유묘에 대하여 농도 의존적으로 활성을 보였으며, F. oxysporum f. sp. raphani에 대한 감수성 품종뿐만 아니라 저항성 품종에 대해서도 유사한 정도의 독성을 나타냈다. 그리고 F. oxysporum f. sp. raphani가 생산하는 fusaric acid는 병원균의 비기주 배추과 작물인 양배추와 브로콜리에 대해서도 강한 활성을 보였다. 따라서 이들 결과는 이 독소가 병원성 관련 독소이나 비기주 특이적 독소이며, 무 시들음병 저항성 검정에서 이 독소가 제거된 포자현탁액을 접종원으로 사용해야 한다는 것을 나타낸다.

• Tuberculosis and Respiratory Diseases
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• 제69권1호
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• pp.39-42
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• 2010

Mycobacterium massiliense is newly identified rapid-growing nontuberculous mycobacterium, but there are no reports of this mycobacterium species being the cause of human illness. We describe one case of Mycobacterium massiliense infection presenting as antibiotic-resistant acute pneumonia that resulted in surgical treatment.

• 한국식물병리학회지
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• 제14권6호
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• pp.618-621
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• 1998

In pseudoperonospora humuli, the cause of hop downy mildew, environmental and host factors affecting laboratory production of oospore were examined. After 7 days incubation of leaf disk inoculated with sporangia on water, additional incubations were carried out under different conditions of temperature and moisture. Oospore production was also compared between very susceptible (Nugget) and resistant (Fuggle) hop cultivars. Oospores were not produced at 18$^{\circ}C$ regardless of other incubation conditions. Leaf disks failed to produce oospore when incubated on water for up to 18 days at 8$^{\circ}C$. No oospores formed on infection sites without necrosis. However, abundant oospores were produced at necrotized infection sites when inoculated leaf disk incubated on dry filter paper for 5 days at 8$^{\circ}C$. Both susceptible and resistant hop cultivars produced abundant oospores. In the measurement of optimal temperature for oospore production, oospores were produced at 6 to 12$^{\circ}C$ Most abundant oospores were produced at 8$^{\circ}C$. We suggest that proper combination of low temperature, dryness and necrosis may be a critical environmental factors for oospore production of P. humuli.

• 한국응용곤충학회지
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• 제32권4호
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• pp.373-381
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• 1993

Resistance evolution to organophosphate-based pesticides in apple and pear inhabiting arthropods of western North America extends to many classes of pest and some beneficial species. Resistance management programs to minimize resistance in pests while exploiting it in natural enemies have met with mixed success. Among beneficials, resistances have been exploited mostly among predators of pest mites. Evolution of resistant mites, leafminers, leafhopper, aphids, leafrollers and some internal fruit feeders have led to development of new monitoring methods and means to delay or avoid resistance. But it is resistance to azinphosmethyl in codling moth (Cydia pomonella) that is changing the pest control system and moving it from chemical to biologically-based means. Newly merging IPM system will depend more on use of biological, cultural, behavior and genetic controls. But more selective pesticides also will be needed to augment pheromones, resistant host plants and genetically altered organisms. These more biologically-based tactics will be prone to resistance evolution in pests as well, if used too unilaterally and/or too extensively.

• The Plant Pathology Journal
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• 제20권3호
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• pp.206-211
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• 2004

Transgenic Nicotiana benthamiana plants harboring coat protein (CP) gene of Zucchini green mottle mosaic virus (ZGMMV) were generated for virus-resistant screening and complementation analysis of related viruses for environmental safety assessment (SA) of living modified organism (LMO) purposes. Transformation of leaf disc of N.benthamiana was performed by using Agrobacterium-mediated method and the pZGC-PPGA748 containing the ZGMMV CP and NPTII genes. Two kinds of transgenic homozygous groups, virus-resistant and virus-susceptible N.benthamiana lines, were obtained by screening of challenging homologous virus for Tl generations. These two pathologically different lines can be useful for host-virus interactions and LMO environmental SA.

• 한국토양비료학회지
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• 제51권1호
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• pp.28-34
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• 2018

Yuzu (Citrus junos) gummosis disease, caused by Phytophthora nicotianae, was first reported in 1997. As known in citrus, Phytophthora is the most fastidious soil-borne pathogen to control. In order to minimize its damage to Citrus spp., integrated pest management (IPM) approach, including fungicide chemicals and resistant cultivars, is necessary. Therefore, in this study we tried to evaluate tolerance of yuzu cultivars and its related species against yuzu Phytophthora. Trifoliate orange was evaluated as a susceptible host to yuzu Phytophthora by both mycelial growth onto extract media and immature fruit inoculation. However, in zoospores spray-inoculation on 2-year-old cuttings tree, trifoliate orange appeared to have a resistant property as showing less than 6% diseased leaf rate. Among yuzu cultivars only 'Namhae No. 1' appeared resistant property against both P. nicotianae and P. citrophthora. The 'Namhae No. 1' showed 5.7% and 10.6% diseased leaf ratio by P. nicotianae and P. citrophthora, respectively. Clearly, in order to reduce damages caused by two yuzu Phytophthora, we suggest that growers may utilize a trifoliate orange as a rootstock and 'Namhae No. 1' as a scion for fruit production.

• Journal of Microbiology and Biotechnology
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• 제33권6호
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• pp.715-723
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• 2023

Microbial biofilms are resilient, immune-evasive, often antibiotic-resistant health challenges, and increasingly the target for research into novel therapeutic strategies. We evaluated the effects of a nutraceutical enzyme and botanical blend (NEBB) on established biofilm. Five microbial strains with known implications in chronic human illnesses were tested: Candida albicans, Staphylococcus aureus, Staphylococcus simulans (coagulase-negative, penicillin-resistant), Borrelia burgdorferi, and Pseudomonas aeruginosa. The strains were allowed to form biofilm in vitro. Biofilm cultures were treated with NEBB containing enzymes targeted at lipids, proteins, and sugars, also containing the mucolytic compound N-acetyl cysteine, along with antimicrobial extracts from cranberry, berberine, rosemary, and peppermint. The post-treatment biofilm mass was evaluated by crystal-violet staining, and metabolic activity was measured using the MTT assay. Average biofilm mass and metabolic activity for NEBB-treated biofilms were compared to the average of untreated control cultures. Treatment of established biofilm with NEBB resulted in biofilm-disruption, involving significant reductions in biofilm mass and metabolic activity for Candida and both Staphylococcus species. For B. burgdorferi, we observed reduced biofilm mass, but the remaining residual biofilm showed a mild increase in metabolic activity, suggesting a shift from metabolically quiescent, treatment-resistant persister forms of B. burgdorferi to a more active form, potentially more recognizable by the host immune system. For P. aeruginosa, low doses of NEBB significantly reduced biofilm mass and metabolic activity while higher doses of NEBB increased biofilm mass and metabolic activity. The results suggest that targeted nutraceutical support may help disrupt biofilm communities, offering new facets for integrative combinational treatment strategies.

• International Journal of Industrial Entomology and Biomaterials
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• 제13권1호
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• pp.31-35
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• 2006

The ubiquitin conjugating enzyme 2 (E2) is core component of ubiquitin proteasome pathway (UPP) which represents a selective mechanism for intracellular proteolysis in eukaryotic cells. The E2 has been implicated in the intracellular transfer of ubiquitin to target protein. We show here the involvement of E2 in antiviral immune of Bombyx mori to Bombyx mori nuclear polyhedrosis virus (BmNPV). In this study, mRNA fluorescent differential display PCR (FDD-PCR) was performed with BmNPV highly resistant silkworm strain NB and susceptible silkworm strain 306. At 24 h post BmNPV infection, FDD-PCR with the arbitrary primer AP34 showed that one cDNA band was down-regulated in the midgut of resistant strain, but highly expressed in susceptible strain. The deduced amino acid sequence of this cDNA clone share 99% identity with the recently published B. mori ubiquitin conjugating enzyme E2 (Genbank NO: DQ311351). Fluorescent quantitative PCR corroborated down regulation of E2 in resistant strain. We there conclude that BmNPV infection evokes strong response of susceptible strain including activation of UPP. BmNPV may evolve escape mechanisms that manipulate the UPP in order to persist in the infected host. In addition, the identification of down-regulation of E2 in resistant strain, as well as structure data, are essential to understanding how UPP operates in silkworm antiviral immune to BmNPV disease.