Global Approaches to Identify Genes Involved during Infection Structure Formation in Rice Blast Fungus,Magnaporthe grisea

Woobong Choi 한국식물병리학회 2003 Plant Pathology Journal Vol.19 No.1

Genomics, the powerful tool for identifying genes involved in the pathogenesis of plant pathogenic fungi

Woobong Choi 한국생명과학회 2005 한국생명과학회 심포지움 Vol.44 No.-

단백질 어레이의 발달과 응용 그리고 전망

최우봉 동의대학교 산업기술개발연구소 2005 産業技術硏究誌 Vol.19 No.-

The early applications of microarrays and detection technologies have been centered on DNA-based applications. The application of array technologies to proteomics is now occurring at a rapid rate. Numerous researchers have begun to develop technologies for the creation of microarrays of protein-based screening tools. The stability of antibody molecules when bound to surfaces has made antibody arrays a starting point for proteomic microarray technology. To minimize disadvantages due to size and availability, some researchers have instead opted for antibody fragments, antibody mimics or phage display technology to create libraries for protein chips. Even further removed from antibodies are libraries of aptamers, which are single-stranded oligonucleotides that express high affinity for protein molecules. A variation on the theme of protein chips arrayed with antibody mimics or other protein capture ligand is that of affinity MS where the protein chips are directly placed in a mass spectrometer for detection. Other approaches include the creation of intact protein microarrays directly on glass slides or chips. Although many of the proteins may likely be denatured, successful screening has been demonstrated. The investigation of protein-protein interactions has formed the basis of a technique called yeast two-hybrid. In this method, yeast "bait" proteins can be probed with other yeast "prey" proteins fused to DNA binding domains. Although the current interpretation of protein arrays emphasizes microarray grids of proteins or ligands on glass slides or chips, 2-D gels are technically macroarrays of authentic proteins. In an innovative departure from the traditional concept of proteinchips, some researchers are implementing microfluidic printing of arrayed chemistries on individual protein spots blotted onto membranes. Other researchers are using in-jet printing technology to create protein microarrays on chips. The rapid growth of proteomics and the active climate for new technology is driving a new generation of companies and academic efforts that are developing novel protein microarray techniques for the future.

Phytophthora Species, New Threats to the Plant Health in Korea

Hyun, Ik-Hwa,Choi, Woobong The Korean Society of Plant Pathology 2014 Plant Pathology Journal Vol.30 No.4

Given the lack of a resistant genetic pool in host plants, the introduction of exotic invasive pathogens can result in epidemics that affect a specific ecosystem and economy. Plant quarantine, which is designed to protect endemic plant resources, is a highly invaluable safeguard that should keep biosecurity with increasing international trade and global transportation. A total of 34 species of plant pathogens including Phytophthora infestans were documented as introduced from other countries into Korea from 1900 to 2010. The genus Phytophthora, classified in oomycetes, includes more than 120 species that are mostly recognized worldwide as highly invasive plant pathogens. After 2000, over 50 new species of Phytophthora were identified internationally as plant pathogens occurring in crops and forest trees. In Korea, Phytophthora is also one of the most serious plant pathogens. To date, 22 species (about one-fifth of known species) of the genus have been identified and reported as plant pathogens in the country. The likelihood of new exotic Phytophthora species being introduced into Korea continues to increase, thus necessitating intensive plant quarantine inspections. As new potential threats to plant health in Korea, six Phytophthora species, namely, P. alni, P. inundata, P. kernoviae, P. pinifolia, P. quercina, and P. ramorum, are discussed in this review with focus on history, disease, biology, management, and plant quarantine issues.

Extracellular Matrix Protein Gene, EMP1, Is Required for Appressorium Formation and Pathogenicity of the Rice Blast Fungus, Magnaporthe grisea

이용환,Namsook Ahn,김순옥,Woobong Choi,Kyung-Hwan Im 한국분자세포생물학회 2004 Molecules and cells Vol.17 No.1

Magnaporthe grisea, the causal fungus of rice blast, forms a specialized infection structure called an ap-pressorium that is crucial for host plant penetration. A cDNA clone of M. grisea, showing strong sequence ho-mology to FEM1 of Fusarium oxysporum and encoding an extracellular matrix protein, was isolated during an expressed sequence tag (EST) analysis of an appres-sorium cDNA library and named extracellular matrix protein 1 (EMP1). Sequence analysis of the corre-sponding genomic clone revealed that EMP1 contains an open reading frame of 685 nucleotides encoding 207 amino acids. The estimated molecular weight of the protein product was 20.5 kDa with a pI of 7.84. It con-tains an 18 amino acid N-terminal secretion signal se-quence, as well as four potential N-glycosylation sites. At its C-terminus, the protein contains a 16 amino acid sequence with the characteristics of a glycosylphos-phatidylinositol (GPI) anchor addition signal. North-ern blot analysis showed that EMP1 transcripts accu-mulate during appressorium formation but not during vegetative growth. An EMP1 null mutant, emp1, gener-ated by targeted gene disruption, exhibited reduced levels of appressorium formation and pathogenicity but no effect on mycelial growth rate or conidiation ability. These data suggest that EMP1 plays important roles in appressorium formation and the pathogenicity of M. grisea.

Extracellular matrix protein gene, EMP1, is required for appressorium formation and pathogenicity of the rice blast fungus, Magnaporthe grisea.

Ahn, Namsook,Kim, Soonok,Choi, Woobong,Im, Kyung-Hwan,Lee, Yong-Hwan Korean Society for Molecular Biology 2004 Molecules and cells Vol.17 No.1

<P>Magnaporthe grisea, the causal fungus of rice blast, forms a specialized infection structure called an appressorium that is crucial for host plant penetration. A cDNA clone of M. grisea, showing strong sequence homology to FEM1 of Fusarium oxysporum and encoding an extracellular matrix protein, was isolated during an expressed sequence tag (EST) analysis of an appressorium cDNA library and named extracellular matrix protein 1 (EMP1). Sequence analysis of the corresponding genomic clone revealed that EMP1 contains an open reading frame of 685 nucleotides encoding 207 amino acids. The estimated molecular weight of the protein product was 20.5 kDa with a pI of 7.84. It contains an 18 amino acid N-terminal secretion signal sequence, as well as four potential N-glycosylation sites. At its C-terminus, the protein contains a 16 amino acid sequence with the characteristics of a glycosylphosphatidylinositol (GPI) anchor addition signal. Northern blot analysis showed that EMP1 transcripts accumulate during appressorium formation but not during vegetative growth. An EMP1 null mutant, emp1, generated by targeted gene disruption, exhibited reduced levels of appressorium formation and pathogenicity but no effect on mycelial growth rate or conidiation ability. These data suggest that EMP1 plays important roles in appressorium formation and the pathogenicity of M. grisea.</P>

서산, 태안 및 고흥 지역에서 마늘 흑색썩음병을 일으키는 Sclerotium cepivorum의 살균제 감수성 조사

김형조(Hyung Jo Kim),최우봉(Woobong Choi),김흥태(Heung Tae Kim) 한국농약과학회 2013 농약과학회지 Vol.17 No.2

Fusarium Wilt of Winter Daphne (Daphne odora Thunb.) Caused by Fusarium oxysporum

Gyoung Hee Kim,Jae-Seoun Hur,Woobong Choi,Young Jin Koh 한국식물병리학회 2005 Plant Pathology Journal Vol.21 No.2

Antifungal Activity of Paenibacillus kribbensis Strain T-9 Isolated from Soils against Several Plant Pathogenic Fungi

Xu, Sheng Jun,Hong, Sae Jin,Choi, Woobong,Kim, Byung Sup The Korean Society of Plant Pathology 2014 Plant Pathology Journal Vol.30 No.1

The bacterial strain T-9, which shows strong antifungal activity, is isolated from the soils of Samcheok, Gangwondo and identified as Paenibacillus kribbensis according to morphological and taxonomic characteristics and 16S rRNA gene sequence analysis. The P. kribbensis strain T-9 strongly inhibits the growth of various phytopathogenic fungi including Botrytis cinerea, Colletotricum acutatum, Fusarium oxysporum f. sp. radicis-lycopersici, Magnaporthe oryzae, Phytophthora capsici, Rhizoctonia solani, and Sclerotium cepivorum in vitro. Also, the P. kribbensis strain T-9 exhibited similar or better control effects to plant diseases than in fungicide treatment through in vivo assays. In the 2-year greenhouse experiments, P. kribbensis strain T-9 was highly effective against clubroot. In the 2-year field trials, the P. kribbensis strain T-9 was less effective than the fungicide, but reduced clubroot on Chinese cabbage when compared to the control. The above-described results indicate that the strain T-9 may have the potential as an antagonist to control various phytopathogenic fungi.

Analysis of Genes Expressed during Pepper-Phytophthora capsici Interaction using EST Technology

Dongyoung Kim(김동영),Jong-Hwan Lee(이종환),Woobong Choi(최우봉) 한국생명과학회 2014 생명과학회지 Vol.24 No.11

고추는 한국, 중국, 멕시코를 포함한 온대 및 아열대 지역을 중심으로 전세계적으로 전형적인 향신료로 식용되고 있으며 그 생산량 및 사용량은 해마다 증가하는 추세에 있다. 고추역병균인 Phytophthora capsici는 고추의 생산에 있어, 질적, 양적으로 많은 피해를 야기하는 식물병원균으로 알려져 있다. 난균강에 속하는 이 병원균은 기주식물의 뿌리, 줄기, 잎과 함께 과실에 이르기까지 식물체 전체를 가해한다. 고추역병의 발병을 분자수중에서 이해하기 위해서는, 발병과정에서 발현되는 유전자에 대한 연구분석이 필수적이며, 이를 위해 최근 개발되어 응용되고 있는 발현서열표지(expressed sequence tags, ESTs)의 분석을 시도하였다. 고추역병균을 접종한후 3일째 발병초기의 고추잎으로부터 추출한 total RNA를 이용하여 고추-고추역병균 발병초기 cDNA library를 구축하였다. 이 cDNA library에서 무작위로 선발된 5,760 clone에 대하여 말단 염기서열 분석을 수행하여 5,148개의 양질의 염기서열을 확보하고 contig assembly에 적용한 결과, 2,990개의 unigenes을 확보하였다. 이들 2,990개의 unigenes에 대한 BLASTX를 이용한 상동성 분석결과, 2,409개가 기존에 알려진 서열과 matching을 보였으며, 이중 606개가 기능적으로 구분되었다. Pepper, consumed as a typical spice food around world, is mainly cultivated in warm countries, including Korea, China, and Mexico. Phytophthora capsici is a pathogen on several economically important crops, including pepper. The oomycete attacks the roots, stems, leaves, and fruit of the host plants. To understand the molecular mechanisms underlying development of the disease, the genes expressed during pepper-P. capsici interaction were explored by analyzing expressed sequence tags (ESTs). A cDNA library was constructed from total RNA extracted from pepper leaves challenged with P. capsici for three days, resulting in an early stage of symptom development for comparable interaction. A comprehensive analysis of single-pass sequencing of 5,760 randomly selected cDNA clones extracted 5,148 high-quality entries for contig assembly, which generated 2,990 unigenes. A homology search of the unigenes with BLASTX resulted in 2,409 matches, of which 606 showed classified functional catalogs.