Tomato yellow leaf curl disease is a devastating disease of tomato (Solanum lycopersicum), which is caused by begomoviruses generally referred to as tomato yellow leaf curl virus (TYLCV). The breeding for TYLCV resistance has been based on the introgression of the Ty-3 resistance locus. Knowledge about the exact location of the Ty-3 on tomato chromosome 6 is needed to understand the genomic organization of the Ty-3 locus. In this study, we conducted a genetic analysis using a segregating population derived from a cross between resistant accession S. lycopersicum “A45” and susceptible accession S. lycopersicum “A39”. The F1 plants showed resistance to TYLCV and F1 was self-pollinated to produce F2 progeny. To screen the TYLCV resistance in 145 F2 plants, a leaf agroinfiltration method was used. F2 plants showed a classical Mendelian seregation (106 resistance : 39 susceptibility) for resistance to TYLCV respectively. SCAR and CAPS markers linked to the Ty-3 were tested for genotyping F2 plants and .genotyping and agroinfiltration results were cosegregated in the newly developed F2 population.

야생벼는 재배벼의 병해충 저항성과 불량환경 적응성 등을 제고할 수 있는 유용한 유전자원으로 평가되고 있다. 농촌진흥청 국립식량과학원에서 국내육성 자포니카 벼 품종인 ‘화성’과 야생벼 O. minuta (BBCC 게놈; Acc.=101141)간의 종간교잡을 통하여 흰잎마름병과 도열병에 저항성인 ‘수원506호’를 육성하였으며, 본 계통에 대한 야생벼 유래 도열병 저항성 유전자의 유전양상 구명 및 유전자위 표지에 대한 연구결과는 다음과 같다.1.반복친인 ‘화성’에 높은 친화성을 발현하는 6개 도열병 균주 검정에서 ‘수원506호’는 반복친 ‘화성’과 5개 비교품종들과 다른 저항성 반응을 보여 이들과 다른 야생벼 유래 도열병 저항성 유전자를 보유하는 것으로 판단되었다.2.분자마커의 유전자형과 도열병 저항성 간의 연관성평가를 수행한 결과, ‘수원506호’의 도열병 저항성에 관여하는 주동유전자위는 12번염색체 중단의 RM101-S10704-RM1337 좌위에 위치하는 것으로 추정되었다.3.STS 마커 S10704에서 확인된 ‘화성’과 ‘수원506호’의 이질적인 유전자형은 해당부위에 야생벼 O. minuta의 염색체 단편이 이입되었다는 것을 증명하였다.4.이 좌위는 적어도 9개의 도열병 저항성 유전자들이 위치하는 것으로 보고된 바 있는데, 추후 정밀분석을 통해 ‘수원506호’의 도열병 저항성 유전자위와 기 보고된 유전자들과의 관계를 분석할 계획이다.

Bacterial blight (BB) of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), is a significant disease in most rice cultivation areas. The present study was performed to identify new BB R-gene conferring resistance to Korea Xoo isolates, derived from IR65482-7-216-1-2 and to construct a physical map of the candidate gene. An F2 population derived from a cross between 11325 and Anda was used to determine the exact position of the nearest recombination event to the target region. The position of the R-gene was delimited by flanking markers, RM1233 and RM5766, on chromosome 11. Of the 56 markers designed in the flanking region, 20 were selected as anchor markers and the R-gene was mapped to a 295kb region on chromosome 11. To narrow down the interval spanning the R-gene, an additionally SSR marker, 20 STS markers, and CAPS marker between RM27320 and ID55.05-79 were developed using rice reference genome information. From the result the gene was defined by RM27320 and ID55.WA18-5 located in the BAC clone OSJNBa0036K13. The physical distance between these two markers is approximately 80kb. In a further study, gene expression analysis against listed candidate genes was investigated using semi-quantitative transcription PCR. These results will useful for future disease breeding as well as gene function studies regarding resistance genes.

Tsw, a single dominant resistant gene against Tomato spotted wilt virus (TSWV), has been mapped on chromosome 10 in Capsicum chinense species. Previously reported molecular markers linked to the Tsw gene are not transferable for all pepper breeding materials. To develop additional markers and do genome-based fine mapping of the Tsw gene, approaches of mapping comparison, pooled transcriptome analysis, and genome walking were applied. Eleven additional SNP molecular markers tightly linked to the Tsw gene were developed using tomato and pepper whole genome sequencing databases. Among them, four SNP markers, SNP7715-1, SNP68-1, SNP17918-1, and SNP1072-1, showed no recombination in two segregating populations of F2 ‘Telmo’ (210 individuals) and ‘SP’ (843 individuals). Three scaffold sequences from the C. annuum BAC database and two BAC clones from the BAC library of C. annuum ‘CM334’ covering the Tsw gene were identified by transcriptome analysis and genome walking. A pepper scaffold sequence covering three pepper scaffold sequences was identified from a final version of the C. annuum BAC database. The Tsw gene was delimited within 149 kb by alignment analysis of two BAC clone sequences and the pepper scaffold sequence. A total of 22 predicted genes were resided in the target region between SNP7715-1 and SNP1072-1 co-segregating markers. Among them, five predicted genes showing annotations of CC/TIR-NBS-LRR resistance proteins, mRNA-6, mRNA-7, mRNA-11, mRNA-12, and mRNA-13, were identified. The transcriptome analysis and gene expression study showed that the mRNA-13 was expressed in ‘PI152225’ but was absent in ‘Special’, demonstrating the mRNA-13 could be a strong candidate gene for the Tsw gene. This result will be favorable for cloning the Tsw gene and developing cultivars which carry the TSWV-resistance gene.

Disease is one of the devastating obstacles in the stable crop production. Numerous agronomical and chemical controls have been developed to overcome this problem, but the former is not sufficient for the maintaining the disease under the economic threshold level and the latter is not free from the environmental regulation. One of the most ideal solutions is resistance breeding. Resistance breeding has been majorly dependent on the resistance (R) genes conferring race-specific vertical resistance effective for limited populations within the pathogen species harboring avirulence (Avr) genes encoding effectors exactly matching with R gene products. In spite of its outstanding efficiency, improper management of above cultivars frequently resulted in the resistance break down due to the appearance and domination of the new races in the field. During the last two decades, mechanisms of disease resistance have been characterized and analyzed in the respect of genetics, biochemistry, molecular biology, cell biology, and evolution. Especially, a growing body of investigations has been focused on the resistance effective for multiple races or even more species of pathogen’s infections and also durable and long-lasting. In this manuscript, we will introduce the investigations searching for durable and broad-spectrum resistance and the considerations for their applications in the crop production will be presented.

The use of functional markers, it is expected to make direct identification about genetic diversity at DNA level and overcome the problem of recombination /linkage. These markers can be used to identify interesting alleles in a breeding program and indirectly select for the trait, saving money, time and labor. Bacterial blight of rice caused by Xanthomonas oryzaepv. Oryzae is a destructive disease in rice production worldwide. No bactericide is effective to control the bacterial blight disease yet. Xa3, which is a gene conferring resistance to BB of the rice plant has been previously characterized by map-based cloning. We have cloned and sequenced the Xa3/xa3 gene in Korean cultivar, Hwayoung, Ilmi and Goun with gene specific primers. Our work detected polymorphisms and PCR-based allele specific SNP markers were developed. Susceptible or resistant individuals from an F2 population developed from across between Milyang244 and Ilmi, Korean germplasms and near isogenic lines carrying BB resistance genes were screened with allele specific markers. We found that the genotype completely matched their phenotype to BB using ASP-primers. These markers could be effective to marker-assisted selection for the Xa3 gene in rice breeding programs.

Plant specific gene family, NAC (NAM, ATAF, and CUC) transcription factors have been characterized for their roles in plant growth, development, and stress tolerance. In this study, we isolated OsNAC69 gene and analysed expression level by inoculation of bacterial leaf blight pathogen, Xanthomonas oryzae pv. oryzae (Xoo). NAC transcription factor family can be divided into five groups (I–V). On the basis of phylogenetic analysis, OsNAC69 was fall into group II. OsNAC69 was strongly induced 1 hr after infected with Xoo. To investigate its biological function in the rice, we constructed vector for overexpression in rice, and then generated transgenic rices. Gene expression of OsNAC69-overexpressed transgenic rice lines were analyzed by northern blot. Analysis of disease resistance to pathogen Xoo, nine OsNAC69-overexpressed transgenic rice lines showing high expression level of OsNAC69 were shown more resistant than wild type. These results suggest that OsNAC69 gene may play regulatory role during pathogen infection.

Rice stripe disease, caused by rice stripe virus (RSV), is one of the major virus diseases in east Asia. The objective of this study was conducted to identify new resistance genetic source to rice stripe virus (RSV) disease. Genetic diversity of 155 rice cultivars was evaluated using 9 co-dominant InDel markers and STS marker ST10. These cultivars were classified into two groups by cluster analysis based on Nei`s genetic distances. The marker showed different band pattern among RSV resistance or susceptible cultivar. In comparison with bioassay for RSV resistance and genotyping using SSR markers showed that Stv-bi and InDel 7 marker observed recombination value within 3.8% and RSV resistance gene was closely related to InDel 7. Also InDel 7 divided as resistance type alleles and susceptible type alleles except for some varieties. Interestingly, 02428, Daw dam, Erguailai, Padi Adongdumarat, PERVOMAJSZKIJ, and Tung Ting Wan Hien 1 showed Japonica type in InDel 7 marker. However, these cultivars revealed resistant to RSV bioassay. These results indicate that those cultivar can be able to get the different gene resistance with Stv-bi gene. Newly identified resistance gene is considered useful for improving RSV resistance in japonica rice. Therefore, we will progress the allelism test and genetic analysis for identification of new gene source.

During the last decade, considerable progress has been made to understand the molecular mechanisms of M. grisea infection in rice plants and 10 rice blast R genes have been identified and characterized via map-based cloning methods. In case of rice germplasm, the genetic backgrounds of each germplasm accessions are not uniform and the evaluation for pathogenicity is difficult. To solve these problems, we applied the single resistance gene markers to rice germplasm accessions. A molecular survey was conducted to identify the presence of major blast resistance (R) gene in 363 accessions of Korea landrace rice germplasm. The results revealed that the resistance gene Pik-p (100%), Pib (98%), Pi-d(t)2 (98%) and Piz (76%) were widely observed in tested rice germplasm, but Pita-2, Pik and Pi39 gene were identified in less than 10 accessions. Most of landrace contain the four or five different resistant genes, but these results was not consist of field nursery screening. 13 accessions were shown the blast resistance in field nursery screening and Pik-p, Pib, Pi-d(t)2 and Piz genes were observed in these accessions. The evaluation results of blast resistance genes in rice germplasm will help in breeding of multi disease resistant varieties.

Japonica rice cultivars exhibit high susceptibility to bacterial blight(BB) disease due to genetic vulnerability in Korea. Korean japonica resistant rice cultivars mainly possess one of the genes, Xa1 or Xa3 for BB resistance. These resistance genes are becoming susceptible to K3a, resulting in serious rice yield reduction. This study was carried out to confirm the effect of xa13 gene pyramiding for developing of japonica rice cultivars resistant to BB pathogen breaking down Xa1 or Xa3. IRBB4 conferring Xa4 gene was resistant to K1(HB01013), K2(HB01014), K3(HB01015), and moderately resistant to K3a(HB01009). IRBB5 having xa5 gene was resistant to K1, K2, K3, and K3a. The recessive gene xa13 was resistant to K1 race but susceptible to K2, K3, and K3a. But Xa21 gene is susceptible to predominant K1 race but resistant to other races such as K2, K3, and K3a. Two genes Xa3 and xa13 were susceptible and Xa4 gene was moderate resistant to 24 isolates. xa5 and Xa21 genes were resistant to all isolates including K3a. When xa13 gene combined Xa4, xa5 and Xa21 genes, effect of xa13 gene pyramiding showed higher resistant reaction than that having singe gene out of Xa4, xa5, and Xa21. The order of resistance against 24 isolates breaking down Xa3 gene was IRBB55(xa13+Xa21) > IRBB53 (xa5+xa13) > IRBB51 (Xa4+xa13).

본 연구는 최근 콩 재배에서 심각한 병으로 대두된 콩 불마름병에 대한 저항성 유전자인 rxp 근접분자표지를 개발하고자 수행하였다. 콩 불마름병은 국내에서 전국적으로 발생하는 심각한 세균병으로 이에 관련하여 세균병 접종을 이용한 저항성 품종과 감수성 품종에 대한 연구가 많이 진행되고 있지만 정확한 유전자의 염기서열이 밝혀져 있지 않고 있다. 본 연구는 콩 불마름병에 저항성 품종 8개체와 감수성 품종 8개체를 이용하여 rxp 유전자 근접분자표지를 확인하기

벼 흰잎마름병은 세계적으로 벼 재배치에서 가장 문제시되는 병해충의 하나이다. 우리나라의 경우 상습발생지를 중심으로 Xa1과 Xa3 이 저항성 유전자로 활용되었으나, 소수의 저항원이 집중적으로 활용됨으로 인해 최근 이병화가 급속히 진행되고 있다. 특히 최근 Xa1과 Xa3 모두를 침해하는 새로운 균계 K3a가 확인됨에 따라 새로운 저항성 유전자의 동정 및 활용의 중요성이 높아가고 있다. 국내육성 자포니카품종 화성벼와 야생벼 O. minuta 간의 종간교잡을 통해 확립된 수원506호의 흰잎마름병에 대한 유전분석을 실시하였다. 수원506호와 통일계 품종인 밀양23호간의 교잡을 통해 확보한 F2 개체들을 활용하여 흰잎마름균주 HB3011 의 접종에 따른 병반장의 변이와 유전자지도 작성에 사용된 SSR 마커의 유전자형간의 연관성분석을 수행하였다. 수원506호의 흰잎마름병 저항성을 지배하며 우성유전자로 작용하는 주동유전인자가 염색체 4변 하단에서 SSR 마커 RM255 에 의해 표지 되었는데, 해당 염색체영역은 Xa1과 Xa2 및 Xa22 등이 보고되었던 영역과 매우 유사할 것으로 추정되었다.

벼멸구 저항성 Bph18 유전자를 가진 SR30071-3-7-23-6-1-1-1계통과 감수성인 '새누리'를 교배하여 육성한 약배양집단 192계통에 대해 벼멸구 저항성 유전자 Bph18이 벼의 수량구성요소에 미치는 영향을 검토하였다. 벼멸구 저항성 유전자 Bph18과 밀접히 연관된 7312.T4A 마커의 유전자형을 분석한 결과, 저항성 유전자형을 가진 계통은 24계통이었고 감수성 유전자형을 가진 계통은 168계통이었다. 벼멸구 저항성 유전자 Bph18은

본 연구는 모로베레칸의 잎도열병 저항성유전자를 탐색하고, 이 저항성유전자와 연관된 분자표지를 탐색하기 위해 수행되었다. 도열병에 이병성인 일품벼와 도열병에 강한 모로베레칸을 교잡하여 육성된 140개 BC3F3 계통을 도열병 균계 반응을 통한 저항성 유전자 탐색에 이용하였다.

Currently, more than 33 resistance gene against bacterial blight(BB) have been identified and used to develop resistant cultivar. IRRI developed near isogenic lines carrying monogenic resistance gene and pyramided genes, IRBB lines. This study was conducted to identify the response of resistance gene to Korean bacterial blight races(K1, K2, K3, and K3a) in IRBB lines. Xa1(IRBB1) was resistant to K1 race and Xa2(IRBB2) was resistant to K1 and K2 race. Xa3(IRBB3 and IRBB203) exploited in many breeding programs in Korea were resistant to K1, K2, and K3 race but susceptible to K3a. Xa4(IRBB4 and IRBB204), xa5(IRBB5 and IRBB205), Xa7(IRBB7 and IRBB207) were resistant to four races. xa8(IRRR8) and Xa11(IRBB11 and IRBB211) showed same reaction of Xa2, resistant to K1 and K2. Xa10(IRBB10 and IRBB210), xa13(IRBB13), Xa14(IRBB14 and IRBB214) showed same reaction of Xa1, resistant to K1. Xa21, identified from the wild rice, Oryza longistaminata, is highly resistant to a broad spectrum of Xoo races. In this study, Xa21 was resistant to K2, K3, and K3a but susceptible to K1 widely spreading in Korea. So, Xa21 may be vulnerable to Korean bacterial blight. But pyramided lines with Xa21 showed high level of resistance to all races of Korea. Pyramided lines with Xa4 which conferred durable resistance in many commercial rice cultivar, xa5 which provides recessive resistance, and other resistance genes showed high level of resistance to Korean bacterial blight races.