• The Plant Pathology Journal
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• 제16권2호
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• pp.105-109
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• 2000

The Pi-b is the rice gene conferring race specific resistance to the blast fungus Magnaporthe grisea race having a corresponding avirulence gene, AVR-Pi-b. All resistant cultivars have two copies of the Pi-b gene, but susceptible cultivars have a single copy of the gene. About 1 Kbp insertion sequence was detected in the open reading frame of the Pi-b gene from the susceptible cv. Nipponbare. The nature of insertion sequence was identified as a solo long terminal repeat (LTR) of new rice Tyl-copia-like retrotransposon. LTR was widely distributed in the rice genome. Various types of different patterns of restriction fragment length polymorphism of LTR were detected in indica cultivars, whereas a single type was detected from japonica cultivars. The insertion of LTR sequence in the Pi-b gene in the susceptible cultivar suggested that retrotransposon-mediated insertional mutation might played an important role in the resistance breakdown as well as evolution of resistance genes in rice.

• 한국유기농업학회지
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• 제19권spc호
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• pp.123-126
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• 2011

To investigate the forecasting of plant disease and insect for an agricultural complex and farm in environment-friendly cultivation of Rice, environment-friendly agricultural five complexs and five farms were selected in Youngam and Naju area, Jonnam, Korea. Preventation objects of plant disease and insect were leaf blast, neck blast, sheath blight, bacterial leaf blight, and hopper. Factors of sheath blight occurrence in environment-friendly agricultural complex were a fast transplanting time and a narrow planting density. Bacterial leaf blight in rice occurred severely in the area under water. Rice growth in environment-friendly agricultural complex was decreased heavy drying by hopper appearance.

• The Plant Pathology Journal
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• 제32권1호
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• pp.8-15
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• 2016

To identify a novel biopesticide controlling rice blast disease caused by Magnaporthe oryzae, 700 plant extracts were evaluated for their inhibitory effects on mycelial growth of M. oryzae. The L. foenum-graecum Herba extract showed the lowest inhibition concentration ($IC_{50}$) of $39.28{\mu}g/ml$, which is lower than the $IC_{50}$ of blasticidin S ($63.06{\mu}g/ml$), a conventional fungicide for rice blast disease. When treatments were combined, the $IC_{50}$ of blasticidin S was dramatically reduced to $10.67{\mu}g/ml$. Since ABC transporter genes are involved in fungicide resistance of many organisms, we performed RT-PCR to investigate the transcriptional changes of 40 ABC transporter family genes of M. oryzae treated with the plant extract, blasticidin S, and tetrandrine, a recognized ABC transporter inhibitor. Four ABC transporter genes were prominently activated by blasticidin S treatment, but were suppressed by combinational treatment of blasticidin S with the plant extract, or with tetrandrine that didn't show cellular toxicity by itself in this study. Mycelial death was detected via confocal microscopy at 24 h after plant extract treatment. Finally, subsequent rice field study revealed that the plant extract had high control efficacy of 63.3% and should be considered a biopesticide for rice blast disease. These results showed that extract of L. foenum graecum Herba suppresses M. oryzae ABC transporter genes inducing mycelial death and therefore may be a potent novel biopesticide.

• Journal of Crop Science and Biotechnology
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• 제10권4호
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• pp.231-236
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• 2007

Differentially expressed genes(DEG) were identified in a rice variety, Sathi, an indica type showing high allelopathic potential against barnyardgrass(Echinochloa crus-galli(L.) Beauv. var. frumentaceae). Rice plants were grown with and without barnyardgrass and total RNA was extracted from rice leaves at 45 days after seeding. DEG full-screening was performed by $GeneFishing^{TM}$ method. The differentially expressed bands were re-amplified and sequenced, then analyzed by Basic Local Alignment Search Tool(BLAST) searching for homology sequence identification. Gel electrophoresis showed nine possible genes associated with allelopathic potential in Sathi, six genes(namely DEG-1, 4, 5, 7, 8, and 9) showed higher expression, and three genes(DEG-2, 3 and 6) showed lower expression as compared to the control. cDNA sequence analysis showed that DEG-7 and DEG-9 had the same sequence. From RT PCR results, DEG-6 and DEG-7 were considered as true DEG, whereas DEG-1, 2, 3, 4, 5, and 8 were considered as putative DEG. Results from blast-n and blast-x search suggested that DEG-1 is homologous to a gene for S-adenosylmethionine synthetase, DEG-2 is homologous to a chloroplast gene for ribulose 1,5-bisphosphate carboxylase large subunit, DEG-8 is homologous to oxysterol-binding protein with an 85.7% sequence similarity, DEG-5 is homologous to histone 2B protein with a 47.9% sequence similarity, DEG-6 is homologous to nicotineamine aminotransferase with a 33.1% sequence similarity, DEG-3 has 98.8% similarity with nucleotides sequence that has 33.1% similarity with oxygen evolving complex protein in photosystem II, DEG-7 is homologous to nucleotides sequence that may relate with putative serin/threonine protein kinase and putative transposable element, and DEG-4 has 98.8% similarity with nucleotides sequence for an unknown protein.

• Mycobiology
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• 제46권4호
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• pp.361-369
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• 2018

The rice blast fungus, Magnaporthe oryzae, is an important pathogen of rice plants. It is well known that genes encoded in the genome have different evolutionary histories that are related to their functions. Phylostratigraphy is a method that correlates the evolutionary origin of genes with evolutionary transitions. Here we applied phylostratigraphy to partition total gene content of M. oryzae into distinct classes (phylostrata), which we designated PS1 to PS7, based on estimation of their emergence time. Genes in individual phylostrata did not show significant biases in their global distribution among seven chromosomes, but at the local level, clustering of genes belonging to the same phylostratum was observed. Our phylostrata-wide analysis of genes revealed that genes in the same phylostratum tend to be similar in many physical and functional characteristics such as gene length and structure, GC contents, codon adaptation index, and level of transcription, which correlates with biological functions in evolutionary context. We also found that a significant proportion of genes in the genome are orphans, for which no orthologs can be detected in the database. Among them, we narrowed down to seven orphan genes having transcriptional and translational evidences, and showed that one of them is implicated in asexual reproduction and virulence, suggesting ongoing evolution in this fungus through lineage-specific genes. Our results provide genomic basis for linking functions of pathogenicity factors and gene emergence time.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.13-13
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• 2017

By the progress of genome sequencing, infrastructures for marker-assisted breeding (MAB) of rice came to be established. Fine mapping and gene isolation have been conducted using the breeding materials derived from natural variations and artificial mutants. Such genetic analysis by the genome-wide dense markers provided us the knowledge about the many genes controlling important traits. We identified several genes or quantitative trait loci (QTL) for heading date, blast resistance, eating quality, high-temperature stress tolerance, and so on. NILs of each gene controlling heading date contribute to elongate the rice harvest period. Determination of precise gene location of blast resistance gene pi21, allowed us to overcome linkage drag, co-introduction of undesirable eating quality. We could also breed the first practical rice cultivar in Japan with a brown planthopper resistance gene bph11 in the genetic back-ground of an elite cultivar. Discovery of major and minor QTLs for good eating quality allowed us to fine-tune of eating quality according to the rice planting area or usage of rice grain. Many rice cultivars have bred efficiently by MAB for several traits, or by marker-assisted backcross breeding through chromosome segment substitution lines (CSSLs) using genetically diverse accessions. We are also systematically supporting the crop breeding of other sectors by MAB or by providing resources such as CSSLs. It is possible to pyramid many genes for important traits by using MAB, but is still difficult to improve the yielding ability. We are performing a Genomic Selection (GS) for improvement of rice biomass and grain yield. We are also trying to apply the genome editing technology for high yield rice breeding.

• 한국육종학회지
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• 제40권4호
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• pp.408-413
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• 2008

벼 조생종 품종 금오3호의 잎도열병 저항성 및 도열병 저항성 연관마커 zt56591과의 관계를 분석한 결과, '03~'07년까지 5년간 전국 14개 지역 잎도열병 밭못자리 검정의 평균 발병정도는 금오3호가 1.6으로 진부벼 3.6, 금오벼 5.3 및 일품벼 6.4에 비해 낮았다. 저항성(0-3) 12개소, 중도 저항성(4-6) 2개소이며, 감수성(7-9)을 보인 곳은 없었다. 도열병 내구저항성에서 병반 면적율이 0.1~5.0%사이로 지속적인 저항성을 보였으며, 29개 균주에 저항성반응을 보였고, 1개 균주에 대해서는 이병성 반응을 보였다. 도열병 저항성과 연관된 DNA marker를 이용하여 분석한 결과 '금오3호'는 도열병 광범위 저항성 유전자로 알려진 Pizt와 연관된 마커 zt56591에 저항성 밴드 패턴을 나타내었다. 또한, 아끼다고마찌/금오3호 RIL집단에서 Pizt 연관마커와 잎도열병 저항성과의 관계를 분석한 결과 조환가가 1.1%로 밀접히 연관되어 있어 '금오3호'와 교배된 후대집단에서 zt56591마커를 이용한 MAS선발도 가능할 것으로 판단되었다.

• The Plant Pathology Journal
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• 제40권3호
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• pp.299-309
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• 2024

The rice blast disease, caused by the fungal pathogen, Magnaporthe oryzae (syn. Pyricularia oryzae), poses a significant threat to the global rice production. Understanding how this disease impacts the plant's microbial communities is crucial for gaining insights into host-pathogen interactions. In this study, we investigated the changes in communities of bacterial and fungal endophytes inhabiting different compartments in healthy and diseased plants. We found that both alpha and beta diversities of endophytic communities do not change significantly by the pathogen infection. Rather, the type of plant compartment appeared to be the main driver of endophytic community structures. Although the overall structure seemed to be consistent between healthy and diseased plants, our analysis of differentially abundant taxa revealed the specific bacterial and fungal operational taxonomic units that exhibited enrichment in the root and leaf compartments of infected plants. These findings suggest that endophyte communities are robust to the changes at the early stage of pathogen infection, and that some of endophytes enriched in infected plants might have roles in the defense against the pathogen.

• 식물병연구
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• 제25권4호
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• pp.196-204
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• 2019

지난 2014년에 전남의 나주, 해남, 영암, 고흥, 장흥 등과, 경남의 밀양, 진주, 고성 등에서 이삭도열병이 심하게 발생하여 벼의 재배면적 대비 발생면적 비율이 전남은 11.0%, 경남은 14.6%에 달하였다. 본 연구에서는 남부지방의 주된 발생지역들에 대하여 2014년 8월의 기상 환경, 품종별 재배 면적 차이, 식물체 질소함량에 따른 이삭도열병 발생 정도에 대하여 분석함으로써, 2014년 남부지방 이삭도열병 대발생의 원인을 구명하였다. 2014년에 각 시도 안에서 10,000 ha 이상 재배된 품종으로는 새누리, 일미벼, 황금누리, 운광, 동진1호, 남평벼 등이 있었다. 2014년의 8월 한 달 동안의 평균기온은 해남과 밀양에서 2018년보다 각각 3.2℃, 3.1℃ 낮고 평년보다 1.5℃, 1.3℃ 낮았다. 강수량은 해남과 밀양에서 2018년보다 각각 70.0%, 42.0% 많고 평년보다 40.1%, 125.7% 많았다. 도열병 감염 위험 예측모형에 의한 8월의 감염 경보 발생일수는 2014년이 2018년보다 많았고, 2014년은 전국적으로 발생일수가 많았다. 식물체의 질소함량은 병 발생이 심한 포장(병든이삭률 60% 이상)이 적은 포장(10% 이하)보다 유의하게 높았다. 결론적으로, 2014년에 특정 지역에서 이삭도열병이 대발생한 것은 감수성 품종이 재배되고 저온과 잦은 강우도 있었지만, 특히 질소질 비료가 다량으로 시용된 점이 특정 필지를 중심으로 다 발생하게 한 주요 원인이었다.

• The Plant Pathology Journal
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• 제19권6호
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• pp.301-304
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• 2003

Gamma-ray irradiation is known to induce various mutations in plants caused by chromosome alterations. This study investigated disease responses of selected gamma-ray induced rice mutants generated from seven Japonica-type rice cultivars against three plant diseases. Among the tested 22 mutants, three gain-of-function mutants and six loss-of-function mutants against rice blast were obtained, as well as three loss-of-function mutants against bacterial leaf blight (BLB). Two of the loss-of-function mutants were susceptible to both rice blast and BLB. Gain-of-function mutation has not been frequently observed in rice plants, thus, the mutants can be used to identify loci of novel genes for the regulation of disease resistant response.