• 식물병연구
• /
• 제19권4호
• /
• pp.265-272
• /
• 2013

전국 7개도 14개 시 군의 주요 고추 재배지에서 시들음 증상을 나타내는 식물체의 땅가 줄기에서 분리 선별된 63개 풋마름병균들의 특성을 조사하였다. 고추에서 분리된 풋마름병균들은 고추(cv. 대왕)와 토마토(cv. 서광)에 강한 병원성을 나타냈다. 모든 병원균들은 배양적, 생리 생화학적 특성 및 특이 PCR 검출에 의하여 Ralstonia solanacearum으로 동정되었다. 고추에서 분리된 63개 풋마름병균들은 race 1 계통으로 2가지 biovar로 구분되었는데, biovar 3은 17개 균주로 27%였고 biovar 4는 46개의 균주로 73%였으며, biovar 4의 생리형이 우점계통이었다. Rep-PCR에 의한 국내 고추 풋마름병균들의 유전적 다양성을 확인한 결과, 70%의 유사성을 기준으로 12개의 group으로 구분되었다. 이러한 결과들은 국내 고추 풋마름병에 대한 방제와 저항성 품종 육성에 중요한 기초 자료를 제공할 것이다.

• 한국어병학회지
• /
• 제22권1호
• /
• pp.35-44
• /
• 2009

Vibrio splendidus biovar II와 V. anguillarum이 우리나라 굴 유생에 있어서 bacillary necrosis를 일으킬 가능성이 있는지를 알아보기 위하여 인위감염을 실시하였다. 부화 후 5일생 유생은 V. splendidus biovar II를 1$1.81{\times}10^{4}$ CFU/$m\ell$ 농도로 인위감염 시켰을 때 8시간 후부터 폐사가 시작되어 16시간에 100% 폐사를 보였다. V. anguillarum을 $1.13{\times}10^{4-5}$ CFU/$m\ell$의 농도로 인위감염 시킨 실험구에서는 20시간 후부터 폐사가 시작 되어 24시간 후 5.55-20%의 폐사율을 보였다. 부화 후 10일생 유생은 V. splendidus biovar II $5.0{\times}10^{5}$ CFU/$m\ell$ 실험구에서 공격 후 8시간째부터 폐사가 나타나기 시작하여 24시간 후 90.47% 폐사하였으나, V. anguillarum 실험구는 $5.08{\times}10^{3-6}$ CFU/$m\ell$의 농도범위에서 폐사가 나타나지 않았다. 그러므로 V. splendidus biovar II는 5일생 유생에 강한 병원성이 있음을 확인하였다. 항균제 처리효과를 구명함으로써 조기 대처방안을 확립하기 위하여 Vibrio를 인위감염 시킨 굴 유생에 폐사가 나타나기 시작할 때 oxytetracycline과 streptomycin을 30 $\mu{g}/m\ell$의 농도로 처리하였다. 그 결과 굴 유생의 유의적인 생존율 증가는 볼 수 없었으나 생존시간이 다소 길어졌으므로 항균제 처리 시점 및 사용농도에 대한 추가연구의 필요성이 제기되었다. 인위감염 실험 시 수조내의 세균농도 분석 결과, V. anguillarum은 $1.13{\times}10^{5}$ CFU/$m\ell$에서 4시간 때 일시적인 증가를 보이다 시간이 경과할수록 $1.7{\times}10^{5}$ CFU/ 로 차츰 감소하는 경향을 보였고, V. splendidus biovar II는 $1.81{\times}10^{4}$ CFU/$m\ell$에서 $1.7{\times}10^{7}$ CFU/로 증가하여 강한 생존력을 보였다. 이와 같은 생존력의 차이는 두 균주간의 병원성 차이를 보이는 결과와 일치하였다. 국내에서는 보고된바 없지만 세계적으로 패류인공종묘에 대량폐사의 원인이 되는 V. splendidus biovar II의 국내산 굴 유생에 대한 병원성이 확인되어 국내에서 도 bacillary necrosis의 발생 가능성이 높음을 알 수 있었다.

• 한국토양비료학회지
• /
• 제50권6호
• /
• pp.562-573
• /
• 2017

Some symbiotic characteristics of native Korean Rhizobium leguminosarum biovar viciae were analysed to get some informations desirable for cultivation of hairy vetch (Vicia villosa Roth) using its symbiont in Korea. The size of indigenous populations of R. leguminosarum biovar viciae was higher in seven upland soils showing $1.7{\times}10^2{\sim}5.8{\times}10^4cells\;g{\cdot}soil^{-1}$, which appeared to be 10% and 37% higher for cultivated and uncultivated soils of hairy vetch, respectively, than seven paddy soils with $1.7{\times}10^2{\sim}1.7{\times}10^4cells\;g{\cdot}soil^{-1}$. In symbiotic potentials, however, the yields of hairy vetch treated with 10-fold-diluted ($10^{-1}$) inoculum and 1000-fold-diluted ($10^{-3}$) one was 11.2% and 8.8% more, respectively, in paddy than upland. Hairy vetch inoculated with either strain KHR 106 from Sacheon or strain KHR 120 from Yesan among native Korean R. leguminosarum biovar viciae isolates was of similar yield increment of 16% (p < 0.05) in upland soils with native R. leguminosarum biovar viciae of $5.8{\times}10cells\;g{\cdot}soil^{-1}$. In case of coinoculation of the two strains, however, the yields was not significantly increased. In especial, isolate KHR 106, KHR 120, and KHR 122 from Suwon, which has also good symbiotic effectiveness, showed different protein profile patterns each other. As a result, hairy vetch is possibly able to use atmospheric nitrogen through symbiotic relationship with diverse native R. leguminosarum biovar viciae in Korean arable lands. For safe and good production of hairy, however, the use of superior strains with high symbiotic effectiveness and competitiveness will be desirable.

• 미생물학회지
• /
• 제25권1호
• /
• pp.17-22
• /
• 1987

For the purpose of securing of strains which can be usefully utilized to study symbiosis between Rhizobium and legume plant, A. tumefaciens T7 was isolated and characterized and then subgroup biovar was determined. A. tumefaciens T7 induced smooth tumor like nopaline type one and did not grow at $37^{\circ}C$ and in the presence of 2% NaCl on yeast extract mannitol medium. The strain was able to grow on the New and Kerr selective media and utilize erythritol but not phenylalanine, tryptophan, and tartarate as a sole carbon source. Negative results were obtained from 3-keto-lactose production and oxidase test. The strain produced alkalifrom malonate and citrate and showed acid litmus milk reaction At least two large plasmids were detected in the cell lysate. According to all of these results, it could be concluded that subdivision of isolated strain was biovar 2.

• Journal of Microbiology and Biotechnology
• /
• 제1권3호
• /
• pp.202-206
• /
• 1991

To produce acetoin as a precursor of the tetramethylpyrazine flavor compound from citrate by Lactococcus lactis ssp. lactis biovar. diacetilactis FC1, fermentation factors such as inital pH of culture media, temperature, concentration of Na-citrate, thiamin-HC1 and sugars were examined. The best acetoin production was achieved with initial pH in the culture media of 5.5, fermentation temperature of $34^{\circ}C$, Na-citrate concentration of 3%, addition of thiamin-HC1 at 2 mg/l and galactose as a carbon source. When fermentation was carried out under the optimum conditions, the exhaustion of Na-citrate and the production of acetoin took simultaneously and acetoin reached the maximum content, 80 mmole/l after 20 hours.

• Journal of Microbiology and Biotechnology
• /
• 제6권2호
• /
• pp.137-141
• /
• 1996

Acetoin and ammonia, the precursors of tetramethylpyrazine (TMP) having "meaty" or "roasted" flavors, were produced by the culture of Lactococcus lactis ssp. lactis biovar. diacetilactis FC1 in free and immobilized cell systems. Cells were immobilized using k-carrageenan and then were incubated at $34^{\circ}C$. The TMP productivity (0.34 g/l) and the conversion ratio (9.3%) of acetoin to TMP of the immobilized cell system were higher than those (0.24 g/l, 7.0%) of the free cell system. When the beads were activated for 12 h, the productivity of acetoin and TMP increased slightly.

• Journal of Microbiology and Biotechnology
• /
• 제4권3호
• /
• pp.191-194
• /
• 1994

Acetoin and ammonia, the precursors of tetramethylpyrazine (TMP) having "nutty " or "roasted" flavors, were produced by cultivating Lactococcus lactis ssp. lactis biovar. diacetilactis FC1. The effects of the volume concentration ratio (VCR) of cell-free medium on the formation of TMP were investigated using a rotary evaporator at $70^{\circ}C than at 80^{\circ}C$. As the VCR increased, the formation of TMP and the conversion ratio of acetoin to TMP increased. More TMP were formed at $70^{\circ}C than at 80^{\circ}C$. As the VCR increased, the concentration of acetoin decreased implying the formation of TMP from acetoin and ammonia.

• The Plant Pathology Journal
• /
• 제30권3호
• /
• pp.299-303
• /
• 2014

This study aims to isolate and identify the causal pathogen of tomato bacterial wilt in Egypt. In 2008, tomato plants showing typical symptoms of bacterial wilt disease with no foliar yellowing were observed in Minia, Assiut and Sohag governorates, Egypt. When cut stems of symptomatic plants were submerged in water, whitish ooze was evident and longitudinal sections showed a brown discoloration in the vascular tissues. Bacteria were isolated on triphenyl tetrazolium chloride medium and fifteen isolates shown typical morphological and cultural characteristics were confirmed as Ralstonia solanacearum biovar 2 race 1. Pathogenicity tests showed that all isolates proved to be pathogenic to tomato plants, varied from 52 to 97% wilting. This is the first report of R. solanacearum biovar 2 race 1 causing bacterial wilt in tomato crop in Egypt.

• 식물병연구
• /
• 제26권1호
• /
• pp.44-47
• /
• 2020

국내에서 분리된 키위 궤양병 원인균인 Pseudomonas syringae pv. actinidiae 균주들에서 스트렙토마이신 저항성 균주가 확인되었다. 2008년부터 2017년 사이에 키위 궤양병이 발병한 111개 과수원에서 분리된 734개 균주의 스트렙토마이신 저항성을 조사하였다. 각 균주의 생존 여부는 100 ㎍/ml의 스트렙토마이신 배지에서 검정하였다. 734개 균주들 중에서 9개 과수원에서 분리된 총 38개 P. syringae pv. actinidiae 균주가 저항성을 나타내었다. Biovar 2에 속하는 저항성 균주들의 경우 몇 개의 특정년도에 발견된 반면, biovar 3에 속하는 저항성 균주들은 2016년 이후에만 발견되었다. 따라서, 키위 궤양병 방제용으로 스트렙토마이신 사용 시 주의해야 하며, 만일 사용하려면 사용 전에 항생제 감수성 테스트가 필요하다.

• The Plant Pathology Journal
• /
• 제22권4호
• /
• pp.318-322
• /
• 2006

One hundred and nine Agrobacterium isolates were recovered from 68 samples(51 plant tumor and 17 soil) that were collected from different habitats in Northern Jordan. The isolated cultures were grouped into 3 biovars based on their biochemical characteristics and biovar I, II, and III comprised a total number of 46, 41, and 22 isolates, respectively. Isolates of biovar I were obtained primarily from the diseased peach, oak and rose plants, whereas isolates of biovar II and ill were obtained mostly from apple and grape plants, respectively. Twenty-nine isolates were found to be virulent to at least one of the tested hosts such as carrots, chickpeas, garden peas and tomato plants with a response of tumor formation or tumor with roots induction. Our result suggested that A. tumefaciens strains from tumor of various plants and soil of Jordan were diverse and they have a variation in their virulence.