• 한국작물학회지
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• 제68권3호
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• pp.134-146
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• 2023

콩 역병(Phytophthora root rot, PRR)은 난균(oomycete)인 Phytophthora sojae에 의해 발생하는 콩의 주요 병 중 하나로, 배수가 잘 안 되는 밭이나 습한 토양에서 심하게 발생한다. 역병의 피해를 효과적으로 줄일 수 있는 방법은 주로 역병 저항성 품종을 재배하는 것으로, 이는 저항성 유전자 Rps (resistance to P. sojae)에 대한 연구를 중심으로 이루어진다. 본 연구는 대풍 과 천알(계통명 SS0404-T5-76)을 교배하여 구축한 RIL (recombinant inbred line) 집단을 이용하여 콩 역병 균주40468과 연관된 저항성 유전자좌를 탐색하기 위해 수행되었다. 역병 균주40468에 대한 저항성 평가는 하배축 접종(hypocotyl inoculation) 방법으로 이루어졌다. 저항성 검정 결과, 천알은 저항성,대풍은 감수성을 보였고 집단 내에서는 계통들의 표현형이 분리되는 양상을 보였다. 집단 내에서 표현형 분포는 1:1 (R:S) (χ2 = 0.57, p = 0.75) 분리비와 일치하였으며, 이는 저항성 반응이 단일 유전자에 의해 조절됨을 나타낸다. 대풍, 천알과 각 RIL 계통들은 고밀도 SNP 유전자형 분석을 통해 데이터를 얻었고, 이를 바탕으로 유전자 지도를 작성하였다. 일원분산 분석(Single-marker ANOVA) 및 linkage analysis 결과, 18번 염색체의 55.9~56.4 Mbp에서 높은 통계적 유의성을 보였으며, 이 지역의 표현형 분산은 ~98%로 나타났다. 탐색된 영역은 다수의 선행연구에서 Rps의 위치로 보고된 지역과 겹치며, 콩 표준 유전체 정보를 기반으로 0.5 Mbp 범위 내에서 leucine-rich repeat (LRR) 또는 serine/threonine kinase(STK)을 합성하는 유전자 9개를 포함하고 있다. 천알은 역병 균주40468에 대한 저항성 유전자좌가 밝혀진 첫 국내 콩 품종으로, 본 연구에서 밝힌 천알의 저항성 유전자좌는 향후 역병 저항성 육종 및 연구에서 유용한 재료가 될 것이다.

• Weed & Turfgrass Science
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• 제2권3호
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• pp.306-311
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• 2013

Pythium aphanidermatum에 의한 잎마름병(pythium blights)이 chewing fescue "Jamestowm II" 품종에서 2011년 6월 상순에 대구대학교 시험포장에서 발생하였다. 잔디에 발병증상은 잎 끝으로부터 잎마름 증상과 뿌리 썩음증상이 나타나고, 잎색은 진한갈색,회 갈색으로 나타났다. 병원균은 병든 잎과 지제부에서 분리를 하였으며, 동정을 위하여 PDA에서 배양하였다. 균사에는 잎 같은 포자가 복잡한 구조로 부풀어져 있고, 균사로부터 구별되지 않은 실같은 포자낭이 있다. 리보소옴 DNA의 염기서열을 분석한 결과, 유전자은행 DB에 P. aphanidermatum 균주 와의 100% 상동성을 나타낸다는 것을 확인하였다. 병원성은 chewing fescue, creeping bentgrass 및 Kentucky bluegrass에서 코흐의 원칙에 따라 확인하였다. 이것은 chewing fescue 종에서 P. aphanidermatum 에 의한 잎마름병을 국내에서 처음보고 한다.

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1605-1613
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• 2010

Twenty-nine P. polymyxa strains isolated from rhizospheres of various crops were clustered into five genotypic groups on the basis of BOX-PCR analysis. The characteristics of several plant growth-promoting factors among the isolates revealed the distinct attributes in each allocated group. Under gnotobiotic conditions, inoculation of pepper roots with P. polymyxa isolates significantly increased the biomass in 17 of total 29 treated plants with untreated plants. Experiments on induced systemic resistance (ISR) against bacterial spot pathogen Xanthomonas axonopodis pv. vesicatoria in pepper by P. polymyxa strains were conducted and only one isolate (KNUC265) was selected. Further studies into ISR mediation by the KNUC265 strain against the soft-rot pathogen Erwinia carotovora subsp. carotovora in tobacco demonstrated that the tobacco seedlings exposed to either bacterial volatiles or diffusible metabolites exhibited a reduction in disease severity. In conclusion, ISR and plant growth promotion triggered by P. polymyxa isolates were systemically investigated on pepper for the first time. The P. polymyxa KNUC265 strain, which elicited both ISR and plant growth promotion, could be potentially used in improving the yield of pepper and possibly of other crops.

• Mycobiology
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• 제43권3호
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• pp.333-338
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• 2015

In a previous study, we identified a Streptomyces sp., A3265, as exhibiting potent antifungal activity against various plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, and Rhizoctonia solani. This strain also exhibited a biocontrolling effect against ginseng root rot and damping-off disease, common diseases of ginseng and other crops. In this study, we isolated two antifungal substances responsible for this biocontrolling effect via Diaion HP-20 and Sephadex LH-20 column chromatography, medium pressure liquid chromatography, and high-performance liquid chromatography. These compounds were identified as guanidylfungin A and methyl guanidylfungin A by spectroscopic methods. These compounds exhibited potent antimicrobial activity against various plant pathogenic fungi as well as against bacteria.

• Journal of Ginseng Research
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• 제44권2호
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• pp.332-340
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• 2020

Background: The valuable medicinal plant Panax ginseng has high pharmaceutical efficacy because it produces ginsenosides. However, its yields decline because of a root-rot disease caused by Ilyonectria mors-panacis. Because species within Ilyonectria showed variable aggressiveness by altering ginsenoside concentrations in inoculated plants, we investigated how such infections might regulate the biosynthesis of ginsenosides and their related signaling molecules. Methods: Two-year-old ginseng seedlings were treated with I. mors-panacis and I. robusta. Roots from infected and pathogen-free plants were harvested at 4 and 16 days after inoculation. We then examined levels or/and expression of genes of ginsenosides, salicylic acid (SA), jasmonic acid (JA), and reactive oxygen species (ROS). We also checked the susceptibility of those pathogens to ROS. Results: Ginsenoside biosynthesis was significantly suppressed and increased in response to infection by I. mors-panacis and I. robusta, respectively. Regulation of JA was significantly higher in I. robusta-infected roots, while levels of SA and ROS were significantly higher in I. mors-panacis-infected roots. Catalase activity was significantly higher in I. robusta-infected roots followed in order by mock roots and those infected by I. mors-panacis. Moreover, I. mors-panacis was resistant to ROS compared with I. robusta. Conclusion: Infection by the weakly aggressive I. robusta led to the upregulation of ginsenoside production and biosynthesis, probably because only a low level of ROS was induced. In contrast, the more aggressive I. mors-panacis suppressed ginsenoside biosynthesis, probably because of higher ROS levels and subsequent induction of programmed cell death pathways. Furthermore, I. mors-panacis may have increased its virulence by resisting the cytotoxicity of ROS.

• The Plant Pathology Journal
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• 제21권4호
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• pp.317-321
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• 2005

Since 2000 severe rots on aerial and underground parts of paprika (Capsicum annum L.) has occurred in most surveyed glasshouses throughout the country. A total of 56 isolates of a fungus were consistently isolated from various plant parts such as fruit, stem, branch, and root collected from 16 farms in five provinces. Anamorph stage of the fungus was identified as Fusarium solani based on its morphological characteristics. However, the fungus readily produced a sexual structure of perithecia on infected plant tissues and on agar media. Since the fungus formed abundant perithecium by a single isolate, it was considered as a homothallic strain of Nectria haematococca, the teleomorph of F. solani. Irregularly globose perithecia with orange to red color formed sparsely to gregariously on dead tissues of fruits and basal stems at the late infection stage, which is a diagnostic sign for the disease. Perithecia ranged from 125 to 220 ${\mu}m$ in diameter varied among isolates. Asci enveloping eight ascospores were cylindrical and measured 60-80x8-12 ${\mu}m$. Ellipsoid to obovate ascospores are two-celled and measured 11-18x4-7 ${\mu}m$. Ascospores were hyaline, slightly constricted at the central septum, and revealed longitudinal striations that is characteristic of the species. This fungus that has never been reported in Korea has previously become a threat to paprika cultivation because of its strong pathogenicity and nationwide distribution.

• The Plant Pathology Journal
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• 제33권4호
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• pp.362-369
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• 2017

White root rot disease, caused by the pathogen Rosellinia necatrix, is one of the world's most devastating plant fungal diseases and affects several commercially important species of fruit trees and crops. Recent global outbreaks of R. necatrix and advances in molecular techniques have both increased interest in this pathogen. However, the lack of information regarding the genomic structure and transcriptome of R. necatrix has been a barrier to the progress of functional genomic research and the control of this harmful pathogen. Here, we identified 10,616 novel full-length transcripts from the filamentous hyphal tissue of R. necatrix (KACC 40445 strain) using PacBio single-molecule sequencing technology. After annotation of the unigene sets, we selected 14 cell cycle-related genes, which are likely either positively or negatively involved in hyphal growth by cell cycle control. The expression of the selected genes was further compared between two strains that displayed different growth rates on nutritional media. Furthermore, we predicted pathogen-related effector genes and cell wall-degrading enzymes from the annotated gene sets. These results provide the most comprehensive transcriptomal resources for R. necatrix, and could facilitate functional genomics and further analyses of this important phytopathogen.

• The Plant Pathology Journal
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• 제36권6호
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• pp.591-599
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• 2020

Phytophthora root and stem rot reduce soybean yields worldwide. The use of R-gene type resistance is currently crucial for protecting soybean production. The present study aimed to identify the genomic location of a gene conferring resistance to Phytophthora sojae isolate 2457 in the recombinant inbred line population developed by a cross of Daepung × Daewon. Singlemarker analysis identified 20 single nucleotide polymorphisms associated with resistance to the P. sojae isolate 2457, which explained ~67% of phenotypic variance. Daewon contributed a resistance allele for the locus. This region is a well-known location for Rps1 and Rps7. The present study is the first, however, to identify an Rps gene locus from a major soybean variety cultivated in South Korea. Linkage analysis also identified a 573 kb region on chromosome 3 with high significance (logarithm of odds = 13.7). This genomic region was not further narrowed down due to lack of recombinants within the interval. Based on the latest soybean genome, ten leucine-rich repeat coding genes and four serine/ threonine protein kinase-coding genes are annotated in this region, which all are well-known types of genes for conferring disease resistance in crops. These genes would be candidates for molecular characterization of the resistance in further studies. The identified R-gene locus would be useful in developing P. sojae resistant varieties in the future. The results of the present study provide foundational knowledge for researchers who are interested in soybean-P. sojae interaction.

• 한국토양비료학회지
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• 제36권3호
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• pp.134-144
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• 2003

생물적 방제균인 Pseudomonas chlororaphis O6는 phenazine, protease와 HCN 등과 같은 여러 가지 2차 대사 산물들을 분비하여 식물병원균의 생육을 억제하였다. 또한 O6 균을 밀종자에 접종하였을 때, F. culmorum에 의한 뿌리 썩음병을 방제하는 효과가 있었다. 오이 뿌리 분비액내의 주 유기산은 fumaric acid, malic acid, benzoic acid, succinic acid 였고, 당으로는 glucose와 fructose가 검출되었으며, 유기산의 농도는 당의 농도보다 10배 정도 높았다. O6 균은 오이 뿌리 분비액을 영양원으로 하는 배지에서 생육하였다. 유기산을 흡수하는데 관여할 것으로 추정되는 O6 균의 dctA 유전자는 1,335 bp의 open reading frame을 가지고 있었으며, 444개의 아미노산으로 구성된 약 47 kD 의 pI가 8.2인 단백질을 암호화하였다. DctA 단백질은 10개의 putative trans-membrane domains를 가지고 있어, 세포막에 내재된 단백질로 추정되었다. 오이의 뿌리 분비액 중 유기산이 O6 균의 뿌리 정착에 중요한 물질로 작용한다면 본 연구에 의해 클로닝된 dctA 유전자는 식물 정착이나 생물적 방제균의 유용 형질의 발현을 연구하는데 중요한 유전자로 이용될 수 있을 것이다.

• 한국토양비료학회지
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• 제33권1호
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• pp.24-31
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• 2000

도라지 재배지 32개 농가의 토양 물리적 성질을 조사하고 근경부패병 발병 및 수량에 미치는 영향을 조사한 결과는 다음과 같다. 발병율과 유효토심은 Y = -0.747X + 88.19($R^2=0.394^{***}$), 토양경도는 Y = 4.36X + 8.93($R^2=0.201^*$), 용적밀도는 Y = 104.7X - 80.99($R^2=0.295^{**}$), 점토함량과는 Y = 1.24X + 14.14($R^2=0.196^*$), 토양공극과 Y= -3.l1X + 215.9($R^2=0.220^*$), 미사함량과는 Y = -0.75X + 67.85($R^2=0.178^*$)의 상관을 나타냈다. 수량은 토심과 Y = 0.263X + 0.971($R^2=0.105^*$), 경도는 Y = -1.712X + 30.60($R^2=0.109^*$), 자갈함량은 Y= -0.9172X + 45.74($R^2=0.113^*$), 점토함량은 Y = -0.688X+32.74($R^2=0.158^*$), 공극률은 Y = 1.974X -93.19($R^2=0.231^*$), 미사함량 Y = 53.05X - 108.65($R^2=0.232^{**}$)의 상관이 있었다. 위의 결과 다년생 도라지 재배적지는 유효토심 1m 이상, 토양경도는 $5kg\;cm^{-2}$ 이하, 용적밀도는 $1.0Mg\;m^{-3}$ 정도, 공극율은 58~63%, 수분함량은 13~17%, 점토함량은 5~10%, 미사함량은 38~64%가 좋은 것으로 나타났으며 토성은 미사질양토가 가장 좋은 것으로 분석되었다.