• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.2
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• pp.162-168
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• 2007

Compatible and incompatible interactions of near-isogenic lines containing one of Xa1, Xa3, and Xa7 resistance genes with Japanese bacterial blight isolates (T7174, T7147, and T7133) were examined in order to determine the variation of bacterial blight resistance and the stability of resistance gene. IRBB 101 line having a Xal gene was compatible (host susceptible) with T7147 and T7133 isolates but incompatible (host resistant) with T7174 isolate at all the tested rice growth stages. IRBB 103 line having a Xa3 gene was susceptible or moderately resistant to the three isolates at seedling and maximum tillering stage but resistant at heading stage. IRBB 101 line having a Xa7 gene was semi-compatible with the three isolates at seedling stage but incompatible at the other growth stages. Overall there were clear differences between compatible and incompatible interactions of rice with Xanthomonas oryzae pv. oryzae races. In the mixed inoculations of compatible and incompatible isolates, the lesion length from near-isogenic lines decreased as the ratios of incompatible races increased. When the distinction between compatible and incompatible isolates was unclear, there was almost no variation of lesion length regardless of mixed ratios. The pathogenicity of the mixed races in the incompatible Interactions increased rather than the individual inoculation whereas the lesion length of compatible interactions was similar to that of the individual inoculation. These data indicate the incompatible races inhibit the virulence of a compatible race but compatible races increase the disease occurrence due to incompatible races. Furthermore, IRBB 107 line that showed resistance to all the isolates at all the tested growth stages was considered as a good parent f3r breeding of resistant variety.

• Research in Plant Disease
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• v.22 no.4
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• pp.297-302
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• 2016

Tomato yellow leaf curl virus (TYLCV) is a viral disease causing severe economic losses on tomato. Practical prevention of the TYLCV disease is to control tabacco whitefly (Bemisia tabaci) or to cultivate TYLCV-resistant tomato cultivars, because no agrochemical products are available to control TYLCV. In this study, TYLCV resistance of the commercial tomato cultivars were evaluated using the DNA markers tightly linked to TYLCV resistance genes Ty-1 and Ty-3 and infection with the TYLCV clones mediated by Agrobacterium. In marker genotyping, resistance alleles were detected from 4 oval type tomato cultivars (Titichal, TY tinny, TY saengsaeng II, TY sense Q). Four cheery type cultiavrs (TY endorphin, TY smartsama, Tiara TY, Olleh TY) and 6 round type cultivars (TY kingdom, TY ace, TY homerun, TY altorang, Dotaerang TY winner, Styx TY). The seedling bioassay indicated that tomato cultivars of the oval type and cherry type showed consistancy in marker genotype and phenotype while slight disease symptom was observed from some round type cultivras (TY ace, TY homerun, Styx TY) with resistance marker genotype. For fruit yields, TY tinny was greater than its control cultivar Titichal in oval types, TY smartsama was greater than its control Smile in cherry type, and TY ace and TY kingdom were greater than their control Dabok. These cutliavrs can be a good choice for high-yielding TYLCV-resistant tomato cultivars.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.2
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• pp.124-133
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• 2011

Bacterial blight (BB), cuased by the vascular pathogen Xanthomonas oryzae pv. oryzae, is one of the major threats in rice fields worldwide. In Korea, two resistance genes against BB, Xa1 and Xa3 had been intensively used for developing high quality japonica rice cultivars. Those traditional resistance sources have being rapidly ified by the adopting of BB pathogen through mutations of the corresponding avr-genes, such as K3a exhibiting high compatibility to both Xa1 and Xa3. To expanding genetic resource against BB in Korea, the Suweon506, an introgression line between a Korean japonica cultivar, Hwaseong and a wild relative, Oryza minuta, was be subjected for genetic analysis owing to the BB resistance. Through association analyses between the pathotyping and genotyping results for each $F_2$ progenies, derived from a cross between Suweon506 and a Tongil type cultivar, Milyang23, a major resistant dominant gene is localized on the subterminal region of rice chromosome 4, where at least three BB resistancde genes, Xa1, Xa2, and Xa22, were reported previously.

• Korean Journal Plant Pathology
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• v.1 no.2
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• pp.122-127
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• 1985

Three rice cultivars, Aichi-asahi, Toyotama and Yamabiko, possessing a resistance gene $Pi-\alpha$ were evaluated for penetration, hyphal growth in the leaf epidermis and lesion formation using 6 isolates of Pyricularia oryzae by treating pre- and post disposing temperatures of $23/15^{\circ}C\;and\;29/21^{\circ}C$ (day/night) regimes, respectively. Percent penetration of the fungus was higher on the seedlings disposed at $29/21^{\circ}C$ regime and more lesions were formed at 7 days after inoculation than at $23/15^{\circ}C$ regime. Degree of hyphal growth and number of host cells with hyphal growth were remarkably increased from 72 to 96 hr after inoculation at $29/21^{\circ}C$ regime. However, lesion formation on the seedlings disposed at $23/15^{\circ}C$ regime was delayed, possibly as a result of the suppressed hyphal growth until 96 hr after inoculation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.3
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• pp.139-141
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• 2003

Disease severity, percent ripened grains, and yield were investigated in the seven mixtures by using near-isogenic lines having different resistant gene(s) to bacterial blight(BB) of rice. The seven mixtures including the four pure stands were inoculated with a 1:1:1 mixture of races $K_1$, $K_2$, and $K_3$ of BB. Among the seven mixtures-ML01, ML02, ML03, MLl2, MLl3, ML23 and ML0123-, disease severiety, percent ripened grains, and yield of ML01 and ML12, respectively did not show significant difference with those of mean values of their components. But degree of disease severity of the other mixtures, respectively -ML02, ML03, MLl3, ML23, and ML0123-was less than the mean of their components. Percent ripened grains and yield of them were higher than those of mean of their components. ML03, MLl3, ML23 and ML0123 comprised of the equal amount of two or four components having different resistant gene, these mixtures appeared to be a desirable combination for delaying spread of the pathogen, stabilizing of the race structure of the pathogen population, and extending durability of a cultivar with monogenic resistance.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.81-91
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• 2011

Rice wild relatives have been recognized as reservoirs of genetic reinforcements to improve cultivating rice against biotic and abiotic stresses. A wild relative, Oryza. minuta(BBCC; Acc. 101141), was hybridized with a Korean Japonica cultivar, 'Hwaseong'(AA), followed by ovule culture and several times of back crossings to overcome high level of sterility. During evaluation of the introgression lines, breeding line exhibited resistance to bacterial blight with reasonable agronomic performances, and nominated as an elite breeding line, the 'Suweon497'. A mapping population, to dissect genetic basis of the resistance, was constructed by using $F_2$ progenies of the 'Suweon497' ${\times}$ 'Milyang23'. Association analysis between SSR marker genotypes and pathogenisity levels of each $F_2$ progeny revealed the end terminal region of rice chromosome 11 as the nesting place for the wild rice derived bacterial blight resistance gene, where at least four other genes, Xa3, Xa4, Xa26 and Xa31, have been reported.

• Horticultural Science & Technology
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• v.31 no.2
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• pp.246-254
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• 2013

Five isolates of Tomato yellow leaf curl virus (TYLCV) collected from various regions of Korea were amplified using PCR and determined the sequences of full-length genome, respectively. The PCR-amplified DNA of each TYLCV isolate was introduced into a binary vector to construct infectious clone containing 1.9 copies of the corresponding viral genome. Various cultivars and breeding lines of tomato were inoculated with Agrobacterium tumefaciens harboring infectious clone of each TYLCV isolate to assess resistance against TYLCV. Susceptible cultivar 'Super-sunread' revealed typical yellowing and narrowing of the upper leaves. In contrast, breeding linesTY12, GC9, GC171, and GC173, which contained the TY-1 and/or TY-3 genes that confer resistance against TYLCV in nature, were completely symptomless, suggesting that the lines were resistant to challenging TYLCV isolates. Symptoms of TYLCV in susceptible tomato cultivars are significantly different from those of TYLCV in the resistant tomato cultivars at 30 days after agroinfiltration. Although genomic DNAs of TYLCV were detected from the breeding lines TY12, GC9, GC171, and GC173 using real-time PCR analysis with specific primers, levels of TYLCV DNA accumulation in the resistant breeding lines were much lower than those of TYLCV DNA accumulation in susceptible tomato cultivars. Similar symptom severity and levels of TYLCV DNA accumulation were observed from TYLCV infections mediated by Bemisia tabaci in the resistant and susceptible tomato cultivars. Concentration of agrobacterium did not affect the response of tomato cultivars against TYLCV inoculation. Taken together, these results suggest that TYLCV inoculation via agroinfiltration is as effective as inoculation through Bemisia tabaci and is useful for breeding programs of TYLCV-resistant tomato.

• Horticultural Science & Technology
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• v.18 no.5
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• pp.594-598
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• 2000

This study was carried out to investigate the tissue-specific expression of ${\beta}$-glucuronidase (gus) gene driven by endosperm-specific promoter (Z4 promoter) in the transgenic tobacco and to find out inheritance pattern of transgene to the next generation. Tobacco (Nicotiana tabaccum cv. Havana SR1) was transformed with Agrobacterium tumerfaciens LBA4404 harboring BV3 construct containing gus gene driven by Z4 promoter and a kanamycin resistant gene. Seven hundred bp PCR products, indicating the presence of npt II gene, were found in the all eight transformants by PCR analysis using nptII primers. To study the expression pattern of the two different kind of promoters, leaf disks of the Z4pro-gus-transformed plants and 35Spro-gus-transformed plants were analyzed histochemically for gus activity. As a result, leaf disks of Z4pro-gus-transformed plants showed very weak and partial positive gus activity. In contrast, leaf disks of 35Spro-gus-transformed plants showed relatively strong positive gus activity. To investigate the expressed position of Z4 promoter, seeds from Z4pro-gus-transformed plants and 35Spro-gus-transformed plants were analyzed histochemically for gus activity. Z4pro-gus-transformed seeds showed positive gus activity restricted to the endosperm. However, the blue-colored product in 35Spro-gus-transformed seeds was observed in all the area including endosperm. Kanamycin resistance assay showed that transgenes were stably inherited to next generation in all lines.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.37-37
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• 2019

벼 재배포장에서 화학약제의 반복적인 사용으로 인한 병원균의 약제내성과 환경오염은 커다란 문제가 되고 있다. 이러한 약제내성을 극복하기 위한 노력의 하나로 유전자수준의 약제내성기작의 규명과 대체물질의 발굴이 필요하다고 사료된다. 이에 본 연구에서는 식물종이 지니는 광범위한 다양성에 주목하였고, 700여 종의 식물추출물을 벼 도열병균에 처리해 균사성장억제효과를 조사하는 선별실험을 실시하였고, 영릉향과 지모추출물이 높은 균사성장억제효과를 보이는 것을 확인했다. 영릉향과 지모 추출물이 화학약제를 대체하는 대안물질로서 가능성을 조사하기위해 균사성장억제능력 확인실험, 분획, HPLC (High Performance Liquid Chromatography), 포자발아 및 부착기 형성확인검정, ABC transporter의 발현조사, 환경독성실험등을 실시했다. 실험 결과, 영릉향과 지모 추출물을 벼 도열병균에 처리하였을 때 약제저항성유전자 ABC transporter의 기능이 저하되고 화학약제에 대한 내성이 감소를 확인했으며, 분획과 HPLC분석을 통해 영릉향과 지모의 유효성분을 확인했다. 또한, 실제 포장에서 영릉향 추출물과 지모 추출물을 사용하여 벼 도열병 방제가를 확인하는 포장시험을 실시한 결과, 각각 63%와 62%의 목 도열병 방제가를 확인 하였으며, 인축환경에 대한 유해성을 조사하기 위해 어류, 설치류, 중치류, 곤충을 대상으로 영릉향 추출물을 처리해 급성독성시험 실시한 결과, 고농도의 투여량에서도 독성이 없는 것을 확인했다. 위의 실험 결과를 토대로, 영릉향과 지모추출물이 화학농약에 의한 환경오염을 막을 수 있고, 인축과 환경에 피해를 입히지 않는 친환경자재로 친환경적인 생물농약의 신소재로서 가능성을 나타냈다고 사료된다.

• Journal of Plant Biotechnology
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• v.38 no.4
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• pp.293-300
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• 2011

This study is conducted to develop an efficient transformation system via particle bombardment with PLBs (Protocorm-like bodies) in Cymbidium. For this, pCAMBIA3301 vector which carries a herbicide-resistant bar gene and gus gene as a reporter gene was used for transformation with Cymbidium cultivars 'Youngflower ${\times}$ masako' line. To select transformants, proper concentration of herbicide, PPT (phosphinotricin), should be determined. As a result, 5 mg/l of PPT was selected as a proper concentration. Further, proper conditions for particle bombardment were determined to obtain a high frequency of transformation. Results showed that 1.0 ${\mu}g$ of DNA concentration, 1,100 and 1,350 psi for helium gas pressure, 1.0 ${\mu}m$ of gold particle and 6 cm of target distance showed the best result for the particle bombardment experiment. Also, pre-treatment with combination 0.2 M sorbitol and 0.2 M mannitol for 4 hrs prior to genetic transformation increased the transformation efficiency up to 2.5 times. Using transformation system developed in this study, 3.2 ~ 4.0 transgenic cymbidium plants can be produced from 100 bombarded PLBs on average. Putative transgenic plants produced in this system confirmed the presence of the bar gene by PCR analysis. Also, leaves from randomely selected five transgenic lines were applied for Basta solution (0.5% v/v) to check the resistance to the PPT herbicide. As a result, three of them showed resistance and one of them showed the strongest resistance with the maintenance of green color as non-transformed plants showed. Using this established transformation system, more genes of interests can be introduced into Cymbidium plants by genetic transformation in the future.