• Journal of Microbiology and Biotechnology
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• 제29권10호
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• pp.1624-1628
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• 2019

Banana planting altered microbial communities and induced the enrichment of Fusarium oxysporum in rhizosphere compared with that of forest soil. Diseased plant rhizosphere soil (WR) harbored increased pathogen abundance and showed distinct microbial structures from healthy plant rhizosphere soil (HR). The enriched taxon of Bordetella and key taxon of Chaetomium together with some other taxa showed negative associations with pathogen in HR, indicating their importance in pathogen inhibition. Furthermore, a more stable microbiota was observed in HR than in WR. Taken together, the lower pathogen abundance, specific beneficial microbial taxa and stable microbiota contributed to disease suppression.

• The Plant Pathology Journal
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• 제24권3호
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• pp.337-351
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• 2008

Host-pathogen interaction in rice bacterial blight pathosystem was analyzed for a better understanding of their relationship and recognition of stable pathogenicity among the populations of Xanthomonas oryzae pv. oryzae. A total number of 52 bacterial strains isolated from diseased leaf samples collected from 12 rice growing states and one Union Territory of India, were inoculated on 16 rice varieties, each possessing known genes for resistance. Analysis of variance revealed that the host genotypes(G) accounted for largest(78.4%) proportion of the total sum of squares(SS), followed by 16.5% due to the pathogen isolates(I) and 5.1% due to the $I{\times}G$ interactions. Application of the Additive Main effects and Multiplicative Interaction(AMMI) model revealed that the first two interaction principal component axes(IPCA) accounted for 66.8% and 21.5% of the interaction SS, respectively. The biplot generated using the isolate and genotypic scores of the first two IPCAs revealed groups of host genotypes and pathogen isolates falling into four sectors. A group of five isolates with high virulence, high absolute IPCA-1 scores, moderate IPCA-2 scores, low AMMI stability index '$D_i$' values and minimal deviations from additive main effects displayed in AMMI biplot as well as response plot, were identified as possessing stable pathogenicity across 16 host genotypes. The largest group of 27 isolates with low virulence, small IPCA-1 as well as IPCA-2 scores, low $D_i$ values and minimal deviations from additive main effect predictions, possessed stable pathogenicity for low virulence. The AMMI analysis and biplot display facilitated in a better understanding of the host-pathogen interaction, adaptability of pathogen isolates to specific host genotypes, identification of isolates showing stable pathogenicity and most discriminating host genotypes, which could be useful in location specific breeding programs aiming at deployment of resistant host genotypes in bacterial blight disease control strategies.

• The Plant Pathology Journal
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• 제17권6호
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• pp.391.2-391
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• 2001

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1999년도 정기총회 및 춘계 학술발표회
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• pp.36.1-36
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• 1999

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2000년도 추계 학술발표회
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• pp.24.1-24
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• 2000

• 한국식물병리학회지
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• 제11권3호
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• pp.282-284
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• 1995

Grey leaf spot on tomato plants was first observed in Sedo-myeon, Puyo-kun, Chungnam province of Korea in 1994. This disease which had not been reported before in Korea exhibited different symptoms from those of other leaf spot diseases on tomato plants. The symptoms were characterized by small irregular-shaped spots on leaves at the initial stage of the infection, subsequent spread and coalescence of the spots throughout the leaves with ultimate necrosis, and abscission from the plants. When healthy tomato plants were inoculated with a conidial suspension of the fungus isolated from the lesion of a diseased plant in a field, the same characteristic symptoms as those in the field were produced. Furthermore, the same pathogen could be reisolated from the lesions formed buy the inoculation. Conidial characteristics of the pathogen were as follows; oblong shape with constricted 3 transverse septa, round-shaped base, round- or point-shaped apex, size of 45~75$\times$12.5~17.5 ${\mu}{\textrm}{m}$, and 3.5 : 1 ratio of length to width. The pathogen was identified as Stemphylium lycopersici and thus this is the first report on the occurrence of grey leaf spot disease on tomato plants caused by s. lycopersici in Korea.

• Journal of Microbiology and Biotechnology
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• 제14권4호
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• pp.872-876
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• 2004

The plant pathogen Erwinia pyrifoliae was infected with bacteriophage PEa1(h), which produced a translucent halo plaque when grown on a lawn of E. pyrifoliae. To investigate the function of an exopolysaccharide (EPS)-depolymerase in the growth of E. pyrifoliae, an EPS-depolymerase gene was synthesized using the PCR method and sequenced. The synthesized gene was then transferred to E. pyrifoliae. The transformed E. pyrifoliae did not produce any ooze, and its growth was inhibited. However, the EPS-depolymerase did not appear to induce cell death. Accordingly, the present results suggest that an EPS-depolymerase may be effective in inhibiting the cell growth or infection of the pathogen E. pyrifoliae.

• The Plant Pathology Journal
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• 제31권1호
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• pp.78-82
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• 2015

In 2011, a leaf blight disease was observed on cosmos (Cosmos bipinnatus) leaves in Nonsan, Korea. The causal pathogen was isolated and identified based on morphological and molecular approaches. Morphological characteristics of the pathogen matched well with the Alternaria cosmosa and also easily distinguishable from Alternaria zinniae reported from cosmos seeds by producing branched beak. Phylogenetically, the pathogen could not be distinguished from A. passiflorae based on the sequence analysis of a combined data set of Alt a1 and gpd genes. However, A. passiflorae was distinguished from the present species by having conidiophores with 4 to 5 conidiogenous loci. The results indicate that the present Alternaria species is A. cosmosa. Pathogenicity tests revealed that the isolate was pathogenic to the leaves of Cosmos bipinnatus. This is the first report of Alternaria blight disease caused by A. cosmosa on cosmos in Korea.

• 한국미생물·생명공학회지
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• 제18권1호
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• pp.98-102
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• 1990

본 실험에서는 채소 등에서 연부병을 유발시키는 원인균의 일종인 Erwinia herbicola의 생육을 저해시키는 bacteriocin 생산균주를 경작지로부터 분리하여 몇 가지 특성을 조사하였다. 분리균주가 생산하는 bacteriocin은 배양 48시간안에서 가장 많은 축적량을 보였고 bacteriocin 생산유전자는 chromosome 상에 있음을 확인하였다. 또한 Erwinia 속의 chromosomal DNA 를 분리하여 EcoRI으로 절단하고 pLAFR3 vector의 EcoRI site에 cloning 하여 bacteriocin을 생성하는 형질전환체, 두 개체를 얻었다. 이들 중 bacteriocin 생산능이 우수한 CH 49 clone의 제한효소 지도를 작성하였다. Vector 내에 삽입된 3.0kb insert 내에 BamHI과 NglII site가 각각 한 개씩 있음을 밝혔다.

• The Plant Pathology Journal
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• 제34권2호
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• pp.126-138
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• 2018

Rice blast caused by Magnaporthe oryzae is a major disease. In the present study, we aimed to identify and evaluate the novel bacterial isolates from rice rhizosphere for biocontrol of M. oryzae pathogen. Sixty bacterial strains from the rice plant's rhizosphere were tested for their biocontrol activity against M. oryzae under in vitro and in vivo. Among them, B. amyloliquefaciens had significant high activity against the pathogen. The least disease severity and highest germination were recorded in seeds treated with B. amyloliquefaciens UASBR9 (0.96 and 98.00%) compared to untreated control (3.43 and 95.00%, respectively) under in vivo condition. These isolates had high activity of enzymes in relation to growth promoting activity upon challenge inoculation of the pathogen. The potential strains were identified based on 16S rRNA gene sequencing and dominance of these particular genes were associated in Bacillus strains. These strains were also confirmed for the presence of antimicrobial peptide biosynthetic genes viz., srfAA (surfactin), fenD (fengycin), spaS (subtilin), and ituC (iturin) related to secondary metabolite production (e.g., AMPs). Overall, the results suggested that application of potential bacterial strains like B. amyloliquefaciens UASBR9 not only helps in control of the biological suppression of one of the most devastating rice pathogens, M. grisea but also increases plant growth along with a reduction in application of toxic chemical pesticides.