• Title/Summary/Keyword: 저병원성

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Low-pathogenic Pinewood Nematode Found in Dead Trees and Resistance of Pines Induced by Its Pre-inoculation (고사목에서 발견되는 저병원성 소나무재선충 및 이의 인공접종에 의하여 유도되는 소나무의 저항성)

  • Park, Seung-Chan;Moon, Yil-Sung;Kim, Dong-Soo
    • Korean journal of applied entomology
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    • v.53 no.2
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    • pp.141-147
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    • 2014
  • Pinewood nematode (PWN: Bursaphelenchus xylophilus) is known to kill pine tree species that are indigenous to countries where the pest was inadvertently imported, but some cultures from the extraction of dead pines do not damage trees. Experiments were conducted to examine the effect of pre-inoculation of these low-pathogenic pinewood nematode on resistance of pine trees against the pest species. The pre-inoculated pine saplings showed induced resistance which lasted for a year, and repeated inoculation of these low-pathogenic nematodes enhanced tree resistance. All nematode samples extracted from dying or dead pines that had been killed not more than three months before the extraction were pathogenic, and most of those extracted from pines that had been killed 2-3 years before were low-pathogenic. When inoculated in pine saplings, number of low-pathogenic nematodes settled, as studied two days after inoculation, was not different from that of pathogenic ones. However, as studied after 30 days of inoculation, rate of reproduction in low-pathogenic nematodes was far lower than that of pathogenic nematodes. The rate of reproduction of several nematode isolates growing on fungal mat media of Botrytis cinerea varied, but three of four low-pathogenic isolates showed same level of reproduction rates as pathogenic ones.

Vegetative Incompatibility and Hypovirulence Conversion of Cryphonectria(Endothia) parasitica(Murr.)Barr (Cryphonectria(Endothia) parasitica(Murr.)Barr의 체세포(體細胞) 불화합성(不和合性)과 저병원성(低病原性) 변환(變換))

  • Lee, Jong-Kyu
    • The Korean Journal of Mycology
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    • v.22 no.4
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    • pp.343-349
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    • 1994
  • One hundred and two virulent(V) strains of Cryphonectria parasitica were isolated from the cankers of American chestnut (Castanea dentata) trees in western Massachusetts, USA. The diversity of vegetative compatibility groups (VCGs) of C. parasitica was investigated. One hundred and two strains represented 54 VCGs; 38 VCGs had only one strain each, 6 VCGs had 2 strains each, and 10 most common VCGs had 52 strains. Great diversity in VCGs may due to the increasing numbers of VCGs with time since the pathogen has been in Massachusetts for 80 years. Ten vegetative compatibility representative strains were selected from the 10 most common VCGs and converted to hypovirulent (H) strains through the pairing and hyphal anastomosis of H strains (4 strains with French dsRNA elements and 17 strains with Italian dsRNA elements). All of the 10 representative strains were converted to H strains by at least more than one of the H strains.

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Changes in Immunological Factors Induced by H9N2 Avian Influenza Challenge in Broilers (저병원성 조류인플루엔자 감염에 따른 육계의 면역인자 변화)

  • Kim, Deok-Hwan;Kim, Kyu-Jik;Noh, Jin-Yong;Lee, Sun-Hak;Song, Chang-Seon;Park, Hae Kyoung;Nahm, Sang-Soep
    • Korean Journal of Poultry Science
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    • v.47 no.4
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    • pp.229-235
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    • 2020
  • Avian influenza virus infection, one of the most important diseases recognized in the poultry industry, is known to cause changes in cytokine and serum protein levels. However, the normal ranges and/or age-dependent changes in important cytokines and serum proteins associated with influenza infection have not been fully elucidated. In this study, the levels of cytokines (interleukin-1β, interleukin-6, and interferon-γ) and serum proteins (vitamin D binding protein and ovotransferrin) were determined in 1-week- to 4-week-old broilers at 1-week intervals after challenge with a low pathogenic influenza virus. The results showed that the physiological levels of cytokines and serum proteins varied with aging during the 4 weeks. The levels of interleukin-1β and interleukin-6 increased from 20% to 35% after influenza infection compared to those in the negative control group, indicating that these cytokines may be used to monitor disease progression.