• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.84.1-84
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• 2003

Magnaporthe grisea, the casual agent of rice blast, forms an appressorium to penetrate its host. Much has been learned about environmental cues and signal transduction pathways, especially those involving CAMP and MAP kinases, on appressorium formation during the last decade. More recently, pharmacological data suggest that calcium/calmodulin-dependent signaling system is involved in its appressorium formation. To determine the role of phosphoinositide-specific phospholipase C (PI-PLC) on appressorium formation, a gene (WPLCl) encoding PI-PLC was cloned and characterized from M. grisea strain 70-15. Sequence analysis showed that MPLCl has alt five conserved domains present in other phospholipase C genes from several filamentous fungi and mammals. Null mutants (mplcl) generated by targeted gene disruption exhibited pleiotropic effects on conidial morphology, appressorium formation, fertility and pathogenicity. mplcl mutants developed nonfunctional appressoria and are also defective in infectious growth in host tissues. Defects in appressorium formation and pathogenicity in mplcl mutants were complemented by a mouse PLCdelta-1 cDNA under the control of the MPLCl promoter. These results suggest that cellular signaling mediated by MPLCl plays crucial and diverse roles in development and pathogenicity of M. grisea, and functional conservation between fungal and mammalian Pl-PLCs.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.1047-1051
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• 2004

The phytopathogenic bacterium Pectobacterium chrysanthemi secretes multiple isozymes of plant cell wall disrupting enzyme such as pectate lyase and cellulase. The cel gene, existing in tandem with the pel gene, was isolated previously [10]. The role of Cel5Z and PelL1 in P. chrysanthemi PY35 pathogenicity on potato tissues was assessed by mutagenizing cloned cel gene and pel gene in tandem and recombining them with the chromosomal alleles. Strains with the Km cassette interposon in pelL1 or a double mutant showed a delay in the appearance of symptoms, suggesting that P. chrysanthemi PY35 pectate lyase PelL1 may playa minor role in soft-rot pathogenesis.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.277-280
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• 2015

In August 2015, we collected samples of gray mold from sweet basil growing in Sachunmeon, Gangneung, Gangwon Province, Korea. Symptoms included extensive growth of mycelia with gray conidia on young leaves, stems, and blossoms. The pathogen was isolated from infected leaves and blossoms and the fungus was cultured on potato dextrose agar. For identification of the fungus, morphology and rDNA sequencing analysis of the fungus were performed, which confirmed its pathogenicity according to Koch's postulates. The results of morphological examinations, pathogenicity tests, and the rDNA sequences of the internal transcribed spacer regions (ITS1 and ITS4) and the three nuclear protein-coding genes G3PDH, HSP60, and RPB2 showed that the causal agent was Botrytis cinerea. This is the first report of gray mold caused by Botrytis cinerea on sweet basil in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.65.1-65
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• 2003

In addition to the five well-characterized genes of Tobacco mosaic virus (TMV), this virus contains a sixth open reading frame (ORF6) that encodes a 4.8 kDa protein. TMV ORF6 overlaps the ORFs encoding the 30 kDa movement protein and the adjacent 17.5 kDa capsid protein. Although the 4.8 kDa protein could not be detected in vivo, alteration of the AUG codons of this ORF resulted in a mutant virus that attenuated the virulence of the mutated TMV in Nicotiana benthamiana, but not N. tabacum (tobacco). These sequence changes did not affect either the replication or movement of the mutated TMV. Expression of TMV ORF6 from the virus expression vector Potato virus X (PVX) intensified the virulence of this virus in N. benthmiana, but not tobacco, while expression of TMV ORF6 from the virus expression vector Tobacco rattle virus enhanced the pathogenicity observed in both N. benthamima and tobacco. Thus, the TMV ORF6 is a host- and virus-specific. virulence factor. However, two separate assays indicated that the TMV 4.8 kDa protein was not a suppression of RNA silencing. A fusion protein formed between the TMV 4.8 kDa protein and the green fluorescent protein was expressed from the PVX vector and localized to plasmodesmata. Possible roles of the 4.8 kDa protein in pathogenicity will be discussed

• The Plant Pathology Journal
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• v.40 no.3
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• pp.235-250
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• 2024

During the infection process, plant pathogenic fungi encounter plant-derived oxidative stress, and an appropriate response to this stress is crucial to their survival and establishment of the disease. Plant pathogenic fungi have evolved several mechanisms to eliminate oxidants from the external environment and maintain cellular redox homeostasis. When oxidative stress is perceived, various signaling transduction pathways are triggered and activate the downstream genes responsible for the oxidative stress response. Despite extensive research on antioxidant systems and their regulatory mechanisms in plant pathogenic fungi, the specific functions of individual antioxidants and their impacts on pathogenicity have not recently been systematically summarized. Therefore, our objective is to consolidate previous research on the antioxidant systems of plant pathogenic fungi. In this review, we explore the plant immune responses during fungal infection, with a focus on the generation and function of reactive oxygen species. Furthermore, we delve into the three antioxidant systems, summarizing their functions and regulatory mechanisms involved in oxidative stress response. This comprehensive review provides an integrated overview of the antioxidant mechanisms within plant pathogenic fungi, revealing how the oxidative stress response contributes to their pathogenicity.

• 한국생물공학회:학술대회논문집
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• 2000.04a
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• pp.584-587
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• 2000

The invasion genes from Salmonella typhimurium were identified by the construction of a cosmid library and subcloning genes into a plasmid vector, pGEM-7Z. The 4.65 kb fragment of the invasion-conferring genomic region of the subclone, pSV6235 was sequenced in both direction. The three open reading frames, which were located at downstream of a promoter region, were designated as sir (Salmonella invasion region)A coding for the 36 amino acids, sirB coding for the 132 amino acids and sirC for the 82 amino acids, respectively. Interesingly, the genomic region of pSV6235 was highly homologous to Yersinia enterocolitica genomic DNA for a high pathogenicity island and Salmonella enteritidis insertion element IS1351 and IS200 DNA. These results show that there could be a significant relationship between S. typhimurium, Y. enterocolitica and S. enteritidis with respect to horizontal evolution process and acquisition of virulence determinants by means of transposon, plasmid or bacteriophage.

• Mycobiology
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• v.45 no.2
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• pp.84-89
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• 2017

Fungi of the Metarhizium genus are a very versatile model for understanding pathogenicity in insects and their symbiotic relationship with plants. To establish a co-transformation system for the transformation of multiple M. robertsii genes using Agrobacterium tumefaciens, we evaluated whether the antibiotic nourseothricin has the same marker selection efficiency as phosphinothricin using separate vectors. Subsequently, in the two vectors containing the nourseothricin and phosphinothricin resistance cassettes were inserted eGFP and mCherry expression cassettes, respectively. These new vectors were then introduced independently into A. tumefaciens and used to transform M. robertsii either in independent events or in one single co-transformation event using an equimolar mixture of A. tumefaciens cultures. The number of transformants obtained by co-transformation was similar to that obtained by the individual transformation events. This method provides an additional strategy for the simultaneous insertion of multiple genes into M. robertsii.

• Journal of Microbiology and Biotechnology
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• v.26 no.5
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• pp.938-945
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• 2016

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most serious threats to rice production. In this study, screening of rice for resistance to BLB was carried out at two different times and locations; that is, in a greenhouse during winter and in an open field during summer. The pathogenicity of Xoo race K1 was tested on 32 Korean rice cultivars. Inoculation was conducted at the maximum tillering stage, and the lesion length was measured after 14 days of inoculation. Five cultivars, Hanareum, Namcheon, Samgdeok, Samgang, and Yangjo, were found to be resistant in both the greenhouse and open-field screenings. Expression of the plant defense-related genes JAmyb, OsNPR1, OsPR1a, OsWRKY45, and OsPR10b was observed in resistant and susceptible cultivars by qRT-PCR. Among the five genes tested, only OsPR10b showed coherent expression with the phenotypes. Screening of resistance to Xoo in rice was more accurate when conducted in open fields in the summer cultivation period than in greenhouses in winter. The expression of plant defense-related genes after bacterial inoculation could give another perspective in elucidating defense mechanisms by using both resistant and susceptible individuals.

• Mycobiology
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• v.46 no.2
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• pp.168-171
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• 2018

In 2016, a severe leaf spot disease was found on Iris ensata Thumb. in Nanjing, China. The symptom was elliptical, fusiform, or irregularly necrotic lesion surrounded by a yellow halo, from which a small-spored Alternaria species was isolated. The fungus was identified as Alternaria iridiaustralis based on morphological characteristics. The pathogenicity tests revealed that the fungus was the causal pathogen of the disease. Phylogenic analyses using sequences of ITS, gpd, endoPG, and RPB2 genes confirmed the morphological identification. This study is the first report of A. iridiaustralis causing leaf spots on I. ensata in China.

• Mycobiology
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• v.48 no.3
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• pp.233-239
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• 2020

A small-spored Alternaria was found from black spots of storaged Koerle pear (Pyrus sinkiangensis), one of the economically important fruit in Xinjiang province, China. The morphology is similar to A. limoniasperae but obviously different in secondary conidiophores and conidial septa. A phylogenetic analysis using sequence datasets of ITS, GAPDH, TEF1, RPB2, Alt a1, OPA10-2, and EndoPG genes revealed that it belonged to the Alternaria alternata complex group. Pathogenicity tests illustrated that the fungus was the causal pathogen of black spot on Koerle pear fruit.