• The Plant Pathology Journal
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• 제36권4호
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• pp.305-313
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• 2020

Host shifting and host expansion of fungal plant pathogens increases the rate of emergence of new pathogens and the incidence of disease in various crops, which threaten global food security. Magnaporthe species cause serious disease in rice, namely rice blast disease, as well as in many alternative hosts, including wheat, barley, and millet. A severe outbreak of wheat blast due to Magnaporthe oryzae occurred recently in Bangladesh, after the fungus was introduced from South America, causing great loss of yield. This outbreak of wheat blast is of growing concern, because it might spread to adjacent wheat-producing areas. Therefore, it is important to understand the host range and population structure of M. oryzae and related species for determining the evolutionary relationships among Magnaporthe species and for managing blast disease in the field. Here, we collected isolates of M. oryzae and related species from various Poaceae species, including crops and weeds surrounding rice fields, in Korea and determined their phylogenetic relationships and host species specificity. Internal transcribed spacer-mediated phylogenetic analysis revealed that M. oryzae and related species are classified into four groups primarily including isolates from rice, crabgrass, millet and tall fescue. Based on pathogenicity assays, M. oryzae and related species can infect different Poaceae hosts and move among hosts, suggesting the potential for host shifting and host expansion in nature. These results provide important information on the diversification of M. oryzae and related species with a broad range of Poaceae as hosts in crop fields.

• 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.

• Mycobiology
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• 제47권4호
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• pp.473-482
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• 2019

Rice blast disease, caused by the ascomycete fungus Magnaporthe oryzae, is one of the most important diseases in rice production. PAS (period circadian protein, aryl hydrocarbon receptor nuclear translocator protein, single-minded protein) domains are known to be involved in signal transduction pathways, but their functional roles have not been well studied in fungi. In this study, targeted gene deletion was carried out to investigate the functional roles of the PAS-containing gene MoPAS1 (MGG_02665) in M. oryzae. The deletion mutant ΔMopas1 exhibited easily wettable mycelia, reduced conidiation, and defects in appressorium formation and disease development compared to the wild type and complemented transformant. Exogenous cAMP restored appressorium formation in ΔMopas1, but the shape of the restored appressorium was irregular, indicating that MoPAS1 is involved in sensing the hydrophobic surface. To examine the expression and localization of MoPAS1 in M. oryzae during appressorium development and plant infection, we constructed a MoPAS1:GFP fusion construct. MoPAS1:GFP was observed in conidia and germ tubes at 0 and 2 h post-infection (hpi) on hydrophobic cover slips. By 8 hpi, most of the GFP signal was observed in the appressoria. During invasive growth in host cells, MoPAS1:GFP was found to be fully expressed in not only the appressoria but also invasive hyphae, suggesting that MoPAS may contribute to disease development in host cells. These results expand our knowledge of the roles of PAS-containing regulatory genes in the plant-pathogenic fungus M. oryzae.

• 한국응용곤충학회지
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• 제13권1호
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• pp.33-39
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• 1974

통일품종이 가지는 도열병 저항성의 요인을 구명하기 위하여 수도체내에 함유하는 질소, 규산 및 Flavonoid함량을 분석하고 시비수준을 달리하여 재배한 풍광에서 이들 성분함량이 도열병 발병율에 미치는 영향을 조사하였다. 1. 수도체내 규산과 Flavonoid 함량은 질소 시비량과 반비례하고 규산 시비량과는 정비례하여 증가하였다. 2. 도열병 상습답에서의 도열병 발병율은 체내 질소함량에 정비례하고 규산함량에 반비례하였다. 3. 도열병에 대하여 저항성인 통일에서는 저항성의 요인이 되는 규산 및 Flavonoid의 체내함량이 이병성인 풍광에 비하여 현저히 높았다. 4. 규화세포의 수는 고엽일수록 많고 생육의 진전에 따라 증가하였으며 풍광에서 보다는 통일에서 현저히 높았다. 5. 이들 체내 성분의 함량은 통일이 갖는 도열병 저항성의 한 요인인 것으로 보였다.

• Bulletin of the Korean Chemical Society
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• 제33권5호
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• pp.1703-1706
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• 2012

Rice blast is the most serious disease of rice due to its harmfulness and its world wide distribution. $Magnaporthe$ $grisea$ is the cause of rice blast disease and destroys rice enough to feed several tens of millions of people each year. Fungicides are commonly used to control rice blast. But $M.$ $grisea$ acquires resistance to chemical treatments by genetic mutations. 2-Phenylimino-1,3-thiazolines were proposed as a novel class of fungicides against $M.$ $grisea$ in the previous study. To develop compounds with a higher biological activity, a new series of 2-phenylimino-1,3-thiazolines was synthesized and its fungicidal activity was determined against $M.$ $grisea$. The QSAR analysis was carried out on a series of 2-phenylimino-1,3-thiazolines. The QSAR results showed the dependence of fungicidal activity on the structural and physicochemical features of 2-phenylimino-1,3-thiazolines. Our results could be used as guidelines for the study of the mode of action and further design of optimal fungicides.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.68.1-68
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• 2003

When plants are infected by plant pathogens, typical disease symptom termed lesion, appears in compatible interaction. Whereas, in incompatible interactions, only small speck of lesions are visible on the leaf surfaces. Hypersensitive response (HR) of plant which is the result of infection by incompatible pathogens, is a well known defense response inducing rapid cell death resulting in complete resistance. However, some rice mutants show spontaneous disease symptoms during the growth stages without interaction with pathogens. We investigated the spontaneous cell death mutant called Blast Lesion Mimic(BLM) generated by EMS mutation, on the relationship with the hypersensitive response as well as resistant characteristics. Accumulation of phenolic compounds were detected around the lesions as lesions develop on leaf surface. Activation of PR gene was detected before the lesion appeared, and that result indicates the defense-related response are started earlier than lesion formation. The BLM mutant showed resistant response to inoculation of Magnaporthe grisea KJ201 with which the wild type Hwacheong is totally susceptible. Informations on the formation of spontaneous lesions and detail analysis of lesion mimic mutants and related genes are very limited to date. It is really important to understand the phenomenon of the defense-related lesion formation for developing resistant cultivar for rice blast pathogens

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2004년도 The 2004 KSPP Annual Meeting & International Symposium
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• pp.48-52
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• 2004

We have found the role of rice mitogen-activated protein kinase kinase kinase (MAPKKK), OsEDR1, as controling hypersensitive response (HR) and increased disease resistance to rice blast fungus Magnaporthe grisea. Generation of transgenic rice plants through introduction of the over-expression construct of OsEDR1 using Agrobacterium-mediated transformation results in lesion mimic phenotype. Up-regulation of defense mechanism was detected through detection of increased transcription level of rice PBZ1 and PR1a. Inoculation of rice blast fungus on the lesion mimic transgenic lines displayed significantly increased resistance. The disease symptoms were arrested like HR responses which are commonly detected in the incompatible interactions. High accumulation of phenolic compounds around developing lesions was detected under UV light. There was variation among transgenic lines on the timing of lesion progression as well as the lesion numbers on the rice leaves. Transgenic lines with few lesions also show increased resistance as well as equal amount of grain yields compared to that of wild type rice cultivar Nipponbare. This is the first report of the MAPKKK as a positive regulator molecule on defense mechanism through inducing HR-like cell death lesion mimic phenotype. The application of OsEDR1 is highly expected for the development of resistant cultivars against rice pathogens.

• 한국응용곤충학회지
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• 제4권
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• pp.1-6
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• 1965

In Korea the most important plant industry is the rice-growing but she has not yet attained self-sufficiency with regard to rice which is the basic food of Korean. In the past, various measures of increasing rice production have been tried with some success but the increasing rate of did not show the sufficient result. Judging from experiences, disease control may be the most important factor which has influence on increasing of rice production in Korea. During the past 60 years three periods divided by the transition of rice diseases were noted, and especially the recent transition attracted much attention . That is, sheath blight and stripe which were minor diseases in the past have promptly spread all over the country and caused heavy losses to rice plant, and also local outbreak of bacterial leaf blight and dwarf were noticed. Various environmental factors are related to such transition of rice disease. Above all, cultivated varieties susceptible to these diseases, increase of application of nitrogenous fertilizer, earlier transplanting and density of transplanting are considered to be lucre closely related to the development of these diseases and successive development of blast. On the other hand. application of forage fungicides such as organic mercury compounds specific to blast contributed to reduce prevalent area if blast in spite of wide spread of susceptible varieties and increase of application of nitrogenous fertilizer. These facts were confirmed by Korean investigators At the present which various diseases to control coexist in the same region, no one variety resistant to all of these diseases is provided and cultural practices for the control of these diseases often do not produce sufficient yield of rice. it is emphasized that a role of pesticides is very great.

• 한국육종학회지
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• 제40권4호
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• pp.394-400
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• 2008

한국에서 육성한 131개 벼 품종을 이용하여 한국과 필리핀 도열병 균주에 대한 저항성 양상을 조사하여 벼 도열병 저항성 육종연구를 위한 기초자료를 얻고자 본 시험을 수행하였다. 1. 한국과 필리핀에서 밭못자리 검정을 실시한 결과, 전체 품종의 평균 잎도열병 발병정도는 한국에서 4.6으로 필리핀에서 2.0보다 2배 이상 높게 나타났으며, 시험품종 가운데 양국에서 저항성 반응이 서로 다르게 나타난 품종의 비율이 60.3%로 나타났다. 2. 양국에서 수집된 도열병 균주를 이용한 유묘접종검정 결과, 한국 수집 도열병 균주들이 필리핀 수집 균주들보다 병원성이 강한 것으로 나타났는데, 시험품종을 침해하는 비율이 가장 높았던 균주는 한국 균주에서는 93-093, 필리핀 균주에서는 92329-9이었으며, 각각 68.7%와 47.3%의 품종 침해비율을 나타내었다. 3. 도열병 저항성 반응이 다른 9개 품종을 이용한 내구저항성 평가 결과, 팔공벼, 섬진벼, 태백벼, 삼강벼, 밀양23호 등 5품종은 한국 및 필리핀 균주를 이용한 연계검정에서 공히 낮은 병반면적율을 나타내어 내구저항성 품종으로 구분되었다. 4. 한국 연계검정에서 내구성이 낮았던 일품벼와 기호벼는 필리핀 균주를 이용한 연계검정에서 일품벼는 내구저항성이 높은 것으로 나타났고, 기호벼는 3차 파종부터 병반면적율이 급격히 증가하는 경향을 나타내어, 품종의 내구저항성 평가는 환경에 존재하는 친환성 균주수와 균주와 품종간 친화성 정도가 병의 진전 및 확산에 함께 관여하는 것으로 판단되었다.

• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 2003년도 정기총회 및 추계학술발표회
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• pp.108.2-109
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• 2003

The Gyeonggi-do Agricultural Research and Extension Services has developed a web-site (www.epilove.com) in collaboration with EPINET to provide information on agricultural weather and rice disease and insect pest management in Gyeonggi-do. Weather information includes near real-time weather data monitored by automated weather stations (AWS) installed at rice paddy fields of 11 Agricultural Technology Centers (ATC) in Gyeonggi-do, and weekly weather forecast by Korea Meteorological Administration (KMA). Map images of hourly air temperature and rainfall are also generated at 309m x 309m resolution using hourly data obtained from AWS installed at 191 locations by KMA. Based on near real-time weather data from 11 ATC, hourly infection risks of rice blast, sheath blight, and bacterial grain rot for individual districts are estimated by disease forecasting models, BLAST, SHBLIGHT, and GRAINROT. Users can diagnose various diseases and insects of rice and find their information in detail by browsing thumbnail images of them. A database on agrochemicals is linked to the system for disease and insect diagnosis to help users search for appropriate agrochemicals to control diseases and insect pests.