• The Plant Pathology Journal
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• 제32권1호
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• pp.53-57
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• 2016

Major diseases in grafted cacti have been reported and Fusarium oxysporum, Bipolaris cactivora, Phytophthora spp. and Collectotrichum spp. are known as causal pathogens. These pathogens can lead to plant death after infection. Therefore, some European countries have quarantined imported cacti that are infected with specific fungal pathogens. Consequently, we developed PCR detection methods to identify four quarantined fungal pathogens and reduce export rejection rates of Korean grafted cacti. The pathogen specific primer sets F.oF-F.oR, B.CF-B.CR, P.nF-P.nR, and P.cF-P.CR were tested for F. oxysporum, B.cactivora, P. nicotinae, and P. cactorum, respectively. The F.oF-F.oR primer set was designed from the Fusarium ITS region; the B.CF-B.CR and P.nF-P.nR primers respectively from Bipolaris and Phytophthora ITS1; and the P.cF-P.CR primer set from the Ypt1protein gene region. The quarantine fungal pathogen primer pairs were amplified to the specific number of base pairs in each of the following fungal pathogens: 210-bp (F. oxysporum), 510-bp (B. cactivora), 313-bp (P. nicotinae), and 447-bp (P. cactorum). The detection limit for the mono- and multiplex PCR primer sets was 0.1 ng of template DNA under in vitro conditions. Therefore, each primer set successfully diagnosed contamination of quarantine pathogens in export grafted cacti. Consequently, our methodology is a viable tool to screen contamination of the fungal pathogen in exported grafted cacti.

• The Plant Pathology Journal
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• 제18권6호
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• pp.301-307
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• 2002

Graft transmission and cytopathological studies of a severe pear disease, pear black necrotic leafspot（PBNLS), were carried out to determine the causal agent of the disease. No evidence was found that a fungal or bacterial pathogen could be the causal agent of the disease. Attempts to transmit the agent by sap-inoculation to other plants including herbaceous hosts failed. How-ever, the pathogen was readily graft-transmitted from symptomatic diseased pears to healthy pears. Graft transmission of the pathogen was also demonstrated by using an indicator plant, PS-95, developed in the laboratory through various grafting methods. Ultrastructural study of the disease revealed the consistent presence of flexuous rod-shaped virus-like particles (VLP) in the symptomatic leaves of both Niitaka cultivar and indicator pear, PS-95. The particles, approximately 12 nm in diameter with undetermined length, occurred in the cytoplasm of mesophyll parenchyma cells. Cells with VLPs also contained fibril-containing vesicles, which are common in cells infected with plant viruses with ssRNA genome. The vesicles were formed at the tonoplast. Based on the symptomatology, the presence of fibril-containing vesicles, and graft-transmissibility, it is believed that the VLPs that occurred on symptomatic leaves of black necrotic leafspot of pear are viral in nature, possibly those of a capillovirus.

• The Plant Pathology Journal
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• 제16권2호
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• pp.55-62
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• 2000

No Abstract.See Full-text

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.9-12
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• 2003

Clubroot disease of curcifer crops caused by Plasmodiophora brassicae had been first reported in 1920 in Korea, and maintained mild occurrence until 1980s. Since 1990s the disease has become severe in alpine areas of Kyonggi and Kangwon, gradually spread to plain fields throughout the country, and remains as the greatest limiting factor for its production. Researches on the disease has begun in late 1990s in our laboratory after experiencing severe epidemics. Survey of occurrence and etiological and ecological studies have been carried out, particularly, on the pathogen physiology, race identification, quantification of soil pathogen population, host spectrum of the pathogen, and control measures.(중략)

• 농업생명과학연구
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• 제50권5호
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• pp.251-255
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• 2016

In year of 2013, anthracnose disease symptoms were observed on stem of stonecrop in a plant resource field, Southern Forest Resource Research Center, Jinju, South Korea. The disease symptoms were appeared 2-5 cm smudged irregular black spot color on the plant stems. Suspected pathogen was isolated from the lesion with surface sterilization method and identified it as Colletotrichum gloeosporioides by morphological characteristics and phylogenetic analyses. Artificially inoculated the isolated pathogen led to the similar disease symptom as originally observed in the field. The fungal pathogen was re-isolated from the inoculated lesion and it exhibited the same characteristics compared to the original isolate. This is the first report of anthracnose of stonecrop grown in open fields, caused by Colletotrichum gloeosporioides in Korea.

• The Plant Pathology Journal
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• 제38권2호
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• pp.102-114
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• 2022

Pectobacterium carotovorum subsp. carotovorum (Pcc) is a gram-negative, broad host range bacterial pathogen which causes soft rot disease in potatoes as well as other vegetables worldwide. While Pectobacterium infection relies on the production of major cell wall degrading enzymes, other virulence factors and the mechanism of genetic adaptation of this pathogen is not yet clear. In the present study, we have performed an in-depth genome-wide characterization of Pcc strain ICMP5702 isolated from potato and compared it with other pathogenic bacteria from the Pectobacterium genus to identify key virulent determinants. The draft genome of Pcc ICMP5702 contains 4,774,457 bp with a G + C content of 51.90% and 4,520 open reading frames. Genome annotation revealed prominent genes encoding key virulence factors such as plant cell wall degrading enzymes, flagella-based motility, phage proteins, cell membrane structures, and secretion systems. Whereas, a majority of determinants were conserved among the Pectobacterium strains, few notable genes encoding AvrE-family type III secretion system effectors, pectate lyase and metalloprotease in addition to the CRISPR-Cas based adaptive immune system were uniquely represented. Overall, the information generated through this study will contribute to decipher the mechanism of infection and adaptive immunity in Pcc.

• The Plant Pathology Journal
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• 제23권2호
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• pp.76-89
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• 2007

CaCDPK4, a full-length cDNA clone encoding Capsicum annuum calcium-dependent protein kinase 4, was isolated from chili pepper (Capsicum annuum L.). Deduced amino acid sequence of CaCDPK4 shares the highest homology with tobacco NpCDPK8 and chickpea CaCDPK2 with 79% identity. Genomic blot analyses revealed that CaCDPK4 is present as a single copy in pepper genome, but it belongs to a multigene family. CaCDPK4 was highly induced when pepper plants were inoculated with an incompatible bacterial pathogen. Induced levels of CaCDPK4 transcripts were also detected in pepper leaves by the treatment of ethephon, an ethylene-inducing agent, and high-salt stress condition. The bacterial-expressed GST-CaCDPK4 protein showed to retain the autophosphorylation activity in vitro. GUS expression driven by CaCDPK4 promoter was examined in transgenic Arabidopsis containing transcriptional fusion of CaCDPK4 promoter. GUS expression under CaCDPK4 promoter was strong in the root and veins of the seedlings. GW (-1965) and D3 (-1377) promoters conferred on GUS expression in response to inoculation of an incompatible bacterial pathogen, but D4-GUS (-913) and DS-GUS (-833) did not. Taken together, our results suggest that CaCDPK4 can be implicated on signal transduction pathway of defense response against an incompatible bacterial pathogen in pepper.

• Molecules and Cells
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• 제27권4호
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• pp.475-480
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• 2009

The transcription of soybean (Glycine max) calmodulin isoform-4 (GmCaM-4) is dramatically induced within 0.5 h of exposure to pathogen or NaCl. Core cis-acting elements that regulate the expression of the GmCaM-4 gene in response to pathogen and salt stress were previously identified, between -1,207 and -1,128 bp, and between -858 and -728 bp, in the GmCaM-4 promoter. Here, we characterized the properties of the DNA-binding complexes that form at the two core cis-acting elements of the GmCaM-4 promoter in pathogen-treated nuclear extracts. We generated GUS reporter constructs harboring various deletions of approximately 1.3-kb GmCaM-4 promoter, and analyzed GUS expression in tobacco plants transformed with these constructs. The GUS expression analysis suggested that the two previously identified core regions are involved in inducing GmCaM-4 expression in the heterologous system. Finally, a transient expression assay of Arabidopsis protoplasts showed that the GmCaM-4 promoter produced greater levels of GUS activity than did the CaMV35S promoter after pathogen or NaCl treatments, suggesting that the GmCaM-4 promoter may be useful in the production of conditional gene expression systems.

• The Plant Pathology Journal
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• 제34권3호
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• pp.163-170
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• 2018

Strawberry Fusarium wilt disease, caused by Fusarium oxysporum f. sp. fragariae, is the most devastating disease in strawberry production. The pathogen produces chlamydospores which tolerate against harsh environment, fungicide and survive for decades in soil. Development of detection and quantification techniques are regarded significantly in many soilborne pathogens to prevent damage from diseases. In this study, we improved specific-quantitative primers for F. oxysporum f. sp. fragariae to reveal correlation between the pathogen density and the disease severity. Standard curve $r^2$ value of the specific-quantitative primers for qRT-PCR and meting curve were over 0.99 and $80.5^{\circ}C$, respectively. Over pathogen $10^5cfu/g$ of soil was required to cause the disease in both lab and field conditions. With the minimum density to develop the wilt disease, the pathogen affected near 60% in nursery plantation. A biological control microbe agent and soil solarization reduced the pathogen population 2-fold and 1.5-fold in soil, respectively. The developed F. oxysporum f. sp. fragariae specific qRT-PCR protocol may contribute to evaluating soil healthiness and appropriate decision making to control the disease.

• 생명과학회지
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• 제21권9호
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• pp.1295-1300
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• 2011

식물체에서 당 조절 인자의 병 저항성 생리적 특성을 살펴보길 위하여, 원형질막에 존재하는 glucose 조절인자인 애기장대 AtPGR 유전자의 과발현 및 RNAi 형질전환체를 사용하였다[3]. AtPGR 유전자는 병원균 처리에 의하여 전사 발현양이 증가하였을 뿐만 아니라, JA와 SA 처리 시에도 AtPGR 전사 발현양이 증가함을 확인하였다. 과발현 형질전환체를 이용하여 병 저항성을 살펴본 결과, AtPGR 유전자는 병원균에 대해 저항성을 유도함을 알수 있었다. 또한 병원균 유도 증가 유전자로 알려진 PDF1.2 및 PR1 유전자 발현 양상을 qPCR을 통해 살펴본 결과, AtPGR 유전자는 PDF1.2 유전자를 SA 경로 하에서는 증가시키는 반면, JA 경로 하에서는 발현 증가량을 감소시키는 경향이 있음을 나타내었고, PR1 유전자의 발현은 JA 경로를 통해 조절할 것으로 생각되어진다. 이러한 결과를 바탕으로, AtPGR 유전자는 glucose 뿐만 아니라 병원균 반응에도 관련되어져 있음을 알 수 있다.