• The Plant Pathology Journal
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• 제28권4호
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• pp.423-427
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• 2012

Pseudomonas syringae pv. actinidiae strains, the causal agents of bacterial canker on kiwifruit, were isolated from Korea and Italy in 2011. Among 87 isolates, a total of six representative strains, three from Korea and three from Italy, were identified on the basis of biochemical and physiological tests. Identities were confirmed by PCR using P. syringae pv. actinidiae-specific primers PsaF1/R2, which amplified a 280-bp DNA fragment. The strains isolated from Korea in this study displayed BOX-PCR patterns similar to those isolated from Italy but different from those isolated previously in Korea or the pathotype P. syringae pv. actinidiae strain. The effector hopA1 and hopH1 genes, which are known to be present in strains isolated recently from France and Italy, were also present in P. syringae pv. actinidiae strains, SYS1, SYS2 and SYS4, isolated from Korea in this work. However, no amplicons of the expected size were obtained from strains previously isolated from Korea and Japan. In addition, the Korean strains isolated in this work belonged to haplotype I for the cts gene identical to those strains isolated from recent outbreaks in Italy. These results suggest that P. syringae pv. actinidiae strains isolated from Korea and examined in this work are a new type of strain similar to those found from recent outbreaks in Italy. This is the first report on the occurrence of cts haplotype I strains of P. syringae pv. actinidiae affecting kiwifruit plants in Korea.

• The Plant Pathology Journal
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• 제19권6호
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• pp.269-273
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• 2003

A total of 57 isolates of Colletotrichum gloeosporioides were recovered from diseased tissues of Hall's crab apple (Malus haliana), 3 cultivars of edible apple (M. pumila var. dulcissima), red pepper (Capsicum annum), and grapevine (Vitis vinifera) fruits. All isolates showed strong virulence on their own host plants. Isolates from edible apple exhibited high level of cultivar specificity in pathogenicity tests. Ten isolates from apple cultivar 'Fuji' were virulent on 'Jonathan' and 'Rall's Genet'. However, 12 isolates from 'Jonathan' and 'Rall's Genet' were not virulent on 'Fuji'. Among the 24 isolates from red pepper, only seven and two isolates were infective on edible apple and grapevine fruits, respectively. All six isolates from grapevine were only virulent on their own host. These isolates were grouped into five vegetative compatibility groups (VCGs), A, B, C, D, and E, by demonstrating heterokaryosis through complementation using nitrate-nonutilizing (nit) mutants. Among them, isolates belong to VCG-A and VCG-D accounted for 24 and 17 isolates； those in VCG-A exhibited wide host range involving Hall's crab apple, all three edible apple cultivars, and red pepper. On the other hand, isolates of VCG-D and VCG-E showed limited host range specific to red pepper and grapevine, respectively. Taken together, the data suggest that among C. gloeosporioides isolates, the concepts of pathotype and/or forma specialis may exist, and that three is a relationship between host specificity and VCG grouping among C. gloeosporioides isolates.

• The Plant Pathology Journal
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• 제26권4호
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• pp.306-312
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• 2010

The pathotypes of Cercospora beticola, causal agent of sugar beet leaf spot disease, were identified by application of pathogenicity test using 100 isolates obtained from the provinces with intensive sugar beet cultivation. For the identification of pathotypes, five sugar beet cultivars were used each with different resistance factors. Cultivar reactions were determined by inoculation of cultivars with the isolates under controlled conditions and measuring disease severity on the $15^{th}$ day according to the 1-9 KWS Scale. Based on the reactions of the five cultivars, a total of 15 pathotypes were detected. All employed sugar beet cultivars were resistant to Pathotype no:1 comprising most of the isolates. Genetic diversity of the causal agent was characterized by AFLP reaction. The products acquired at the end of AFLP reaction were detected by means of Beckman CEQ 8800 DNA Capillary Series Analysis and the results obtained were evaluated according to the similarity index UPGMA. For the genetic analysis of C. beticola isolates, 9874 polymorphic fragments of sizes between 100 and 500 bp were analysed which were generated by nine primers. The dendrogram derived from AFLP analysis depicted the existence of five different subgroups. The polymorphism rate among isolates was 91.13% and the dendrogram distribution of the pathotypes obtained by pathogenicity indicated that pathotypes were not discriminated and did not compose any groups.

• The Plant Pathology Journal
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• 제37권5호
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• pp.476-488
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• 2021

Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot for cruciferous vegetables worldwide, especially for the cole crops such as cabbage and cauliflower. Due to the lack of resistant cabbage cultivars, black rot has brought about considerable yield losses in recent years in China. Understanding of the pathogen features is a key step for disease prevention, however, the pathogen diversity, population structure, and virulence are largely unknown. In this study, we studied 50 Xcc strains including 39 Xcc isolates collected from cabbage in 20 regions across China, using multilocus sequence genotyping (MLST), repetitive DNA sequence-based PCR (rep-PCR), and pathogenicity tests. For MLST analysis, a total of 12 allelic profiles (AP) were generated, among which the largest AP was AP1 containing 32 strains. Further cluster analysis of rep-PCR divided all strains into 14 DNA groups, with the largest group DNA I comprising of 34 strains, most of which also belonged to AP1. Inoculation tests showed that the representative Xcc strains collected from diverse regions performed differential virulence against three brassica hosts compared with races 1 and 4. Interestingly, these results indicated that AP1/DNA I was not only the main pathotype in China, but also a novel group that differed from the previously reported type races in both genotype and virulence. To our knowledge, this is the first extensive genetic diversity survey for Xcc strains in China, which provides evidence for cabbage resistance breeding and opens the gate for further cabbage-Xcc interaction studies.

• The Plant Pathology Journal
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• 제40권3호
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• pp.329-335
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• 2024

Phytophthora root and stem rot (PRR), caused by Phytophthora sojae, can occur at any growth stage under poorly drained and humid conditions. The expansion of soybean cultivation in South Korean paddy fields has increased the frequency of PRR outbreaks. This study aimed to identify four P. sojae isolates newly collected from domestic fields and evaluate race-specific resistance using the hypocotyl inoculation technique. The four isolates exhibited various pathotypes, with GJ3053 exhibiting the highest virulence complexity. Two isolates, GJ3053 and AD3617, were screened from 205 soybeans, and 182 and 190 genotypes (88.8 and 92.7%, respectively) were susceptible to each isolate. Among these accessions, five genotypes resistant to both isolates were selected. These promising genotypes are candidates for the development of resistant soybean cultivars that can effectively control PRR through gene stacking.

• 한국가금학회지
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• 제44권2호
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• pp.93-102
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• 2017

본 연구에서 NDV의 L유전자와 F유전자를 표적 부위로 각각 제작한 primer 세트를 사용함으로써 하나의 PCR 튜브에서 NDV 검출(386 bp의 증폭 크기)과 함께 병원성 NDV(229 bp의 증폭 크기)를 동시에 감별 증폭할 수 있는 dRT-PCR 검사법을 개발하였다. 개발된 dRT-PCR검사법은 NDV를 특이적으로 검출하고, 병원성을 감별하였다. 특히 국내 병성감정 실시기관에서 적용 중인 기존의 RT-PCR 상용키트에서는 검출하지 못하는 class I NDV과 PPMV(class II 유전형 VI형)을 NDV를 검출함과 동시에 병원성 NDV도 감별가능하였다. 개발된 dRT-PCR 검사법의 검출 민감도는 약 $10^{3.0}EID_{50}/0.1mL$로 평가되었다. 또한 ND발생국의 야외 시료에 적용했을 때, NDV 공통항원 검출율은 94.4%였으며, 병원성 NDV 검출율은 100%이었다. 그러므로 본 연구에서 개발한 dRT-PCR 검사법은 의심축 사례에서 ND를 신속 정확하게 진단하는 데 유용할 진단 방법을 제공할 수 있을 것으로 판단된다.

• 한국균학회소식:학술대회논문집
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• 한국균학회 2015년도 춘계학술대회 및 임시총회
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• pp.41-41
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• 2015

BSA-seq technologies, combined Bulked Segregant Analysis (BSA) and Next-Generation Sequencing (NGS), are making it faster and more efficient to establish the association of agronomic traits with molecular markers or candidate genes, which is the requirement for marker-assisted selection in molecular breeding. Clubroot disease, caused by Plasmodiophora brassicae, is a serious threat to Brassica crops. Even we have breed new clubroot resistant varieties of Chinese cabbage (B. rapa ssp. pekinesis), the underlying genetic mechanism is unclear. In this study, an $F_2$ population of 340 plants were inoculated with P. brassicae from Xinye (Pathotype 2 on the differentials of Williams). Resistance phenotype segregation ratio for the populations fit a 3:1 (R:S) segregation model, consistent with a single dominant gene model. Super-BSA, using re-sequencing the parents, extremely R and S DNA pools with each 50 plants, revealed 3 potential candidate regions on the chromosome A03, with the most significant region falling between 24.30 Mb and 24.75 Mb. A linkage map with 31 markers in this region was constructed with several closely linked markers identified. A Major QTL for clubroot resistance, CRq, which was identified with the peak LOD score at 169.3, explaining 89.9% of the phenotypic variation. And we developed a new co-segregated InDel marker BrQ-2. Joint BSA-seq and traditional QTL analysis delimited CRq to an 250 kb genomic region, where four TIR-NBS-LRR genes (Bra019409, Bra019410, Bra019412 and Bra019413) clustered. The CR gene CRq and closely linked markers will be highly useful for breeding new resistant Chinese cabbage cultivars.

• 식물병연구
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• 제16권3호
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• pp.224-231
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• 2010

1999년부터 2004년 사이에 벼흰잎마름병의 원인균인 Xanthomonas oryzae pv. oryzae를 전국적으로 분리하여 Biolog와 지방산 분석법을 이용하여 동정하였다. 한국의 벼 판별품종을 기준으로 분류한 결과 1999년도와 2002에 각각 분리된 벼흰잎마름병균은 모두 K1 레이스에 속하였다. 2003년도에 분리된 벼흰잎마름병균의 경우는 50% 이상이 K3 레이스에 속하였으며 대부분 전라도 지역에서 분리된 균주였다. 분리 년도 별로 단인자 벼 저항성 품종에 대한 균들의 반응을 보았을 때 많은 K1 레이스로 분류된 균주들이 단인자 저항성 품종에 대해 달리 반응을 보였다. Southern bolt 결과, 동일한 레이스에서도 다양한 비병원성 유전자들을 가지고 있었다. 이러한 결과들은 하나의 레이스가 여러 개의 벼 저항성 유전자와 반응한다는 것을 제시한다. 전남과 전북에서 분리된 모든 K3 레이스들은 Xa3 단인자 저항성 품종을 침해하였는데 이러한 결과는 전남과 전북에 Xa3 저항성원을 지닌 벼 품종의 과다한 재배로 인하여 Xa3 침해 균주의 선별적 증식이 유도된 것으로 추측된다. 이러한 다양한 비병원성 유전자 패턴 및 단인자 저항성 유전자에 대한 반응을 고려하여 국내 분리된 벼흰잎마름병균들을 19개의 병원형으로 분류하였다. 새롭게 분류된 병원형들은 국내의 새로운 저항성 품종을 육종하는데 도움이 될 것이다.

• 식물병연구
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• 제23권3호
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• pp.249-255
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• 2017

벼 도열병은 벼를 재배하는 지역에서는 가장 중요한 병 중 하나이다. 특히, 벼 도열병균은 기주인 벼와 Gene-for-Gene 상호작용이 적용 가능한 대표적인 모델 식물병원성 곰팡이다. 우리나라는 1980년 이래로 벼 도열병균의 레이스를 분석하기 위해 8개의 판별 품종을 이용한 시스템을 구축하여 분류하였다. 그러나 이 판별 품종이 어떤 저항성 유전자를 가지고 있는지에 관해 명확한 정보가 없어 새로운 레이스의 출현이나 병 저항성 붕괴 등에 대하여 과학적인 분석이 어려웠다. 최근 병원균의 레이스와 벼의 저항성 유전자의 상호작용 이해를 돕기 위해 LTH 품종에 단인자 저항성 계통을 각각 다르게 도입한 판별시스템이 개발되었다. 본 연구에서는 우리나라의 1995년부터 2015년까지 분리된 4개의 다른 레이스 KI101, KI201, KI401 및 KJ101로부터 총 50개 균주를 선발하여 LTH 품종에 기반한 단인자 저항성 계통에 접종하여 그 결과를 이전 레이스와 비교 분석해 보았다. 그 결과 한국형 판별시스템으로 분류된 동일 레이스내의 균주들이 단인자 계통에서 서로 다른 반응을 보였다. 이 결과 동일 레이스에 속하는 균주들이 서로 다른 비병원성 유전자를 지닌 것을 의미하며, 더 나아가 새로운 저항성 벼 품종 육종에 유용한 정보를 제공하기 어려울 것으로 추정되었다. 이 연구 결과 현재의 판별시스템과 더불어 단인자 저항성 품종을 통한 판별시스템 도입이 요구되었다. 이 연구 결과는 향후 한국의 판별시스템 개발에 기초 자료로 활용 될 수 있을 것이다.

• 원예과학기술지
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• 제30권3호
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• pp.286-293
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• 2012

고추에 있어서 Tobamovirus 저항성은 고추 염색체 11번 긴 팔 끝부분에 위치한 L 유전자좌의 다섯 개 대립유전자($L^0$, $L^1$, $L^2$, $L^3$, and $L^4$)에 의해 조절된다고 알려져 있다. 표현형 분석 없이 L 대립유전자를 구분할 수 있는 분자표지를 개발하기 위해서 다섯 개의 고추 판별 계통{Capsicum annuum Early California Wonder(ECW, $L^0L^0$), C. annuum Tisana($L^1L^1$), C. annuum Criollo de Morelos 334(CM334,$L^2L^2$), Capsicum chinense PI 159236($L^3L^3$), and Capsicum chacoense PI 260429($L^4L^4$)}을 식물재료로 사용하였다. 대립유전자 특이적 분자표지는 고추 판별 계통에 대해 $L^3$ 연관 분자표지(189D23M, A339, and 253A1R)와 BAC 염기서열(FJ597539 and FJ597541)의 PCR 증폭산물 염기서열을 비교 분석하여 개발되었다. 총 53개의 상용 고추 품종 중 48개에서 분자표지에 의한 추정 유전자형과 Tobamovirus{Tobacco mosaic virus(pathotype 0, $P_0$), Tomato mosaicvirus($P_1$), and Pepper mild mottle virus($P_{1,2}$)} 접종 표현형과 일치했다. 결과적으로 본 연구에서 개발된 분자표지는 고추 육종에 있어서 TMV 저항성 도입에 필요한 선발마커로 충분히 활용될 수 있을 것이다.