• 한국식물병리학회:학술대회논문집
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• 한국식물병리학회 1994년도 Proceedings of International Symposium on BIOLOGICAL CONTROL OF PLANT DISEASES Korean Society of Plant Pathology
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• pp.50-61
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• 1994

Biological control of important fungal diseases such as Phytophthora blight of red pepper, gary mold rot of vegetables, and powdery mildew of many crops was attempted using an antagonistic bacterium, Bacillus sp. AC-1 in greenhouses and fields. The antagonistic bacterium isolated from the rhizosphere soils of healthy red pepper plant was very effective in the inhibition of mycelial growth of plant pathogenic fungi in vitro including Phytophthora capsici, Rhizoctonia solani, Pyricularia oryzae, Botrytis cinerea, Valsa mali, Fusarium oxysporum, Pythium ultimum, Alternari mali, Helminthosporium oryzae, and Colletotrichum gloeosporioides. Culture filtrate of antagonistic Bacillus sp. AC-1 applied to pot soils infested with Phytophthora capsici suppressed the disease occurrence better than metalaxyl application did until 37 days after treatment in greenhouse tests. Treatments of the bacterial suspension on red pepper plants also reduced the incidence of Phytophthora blight in greenhouse tests. In farmers' commercial production fields, however, the controlling efficacy of the antagonistic bacteria was variable depending on field locations. Gray mold rot of chinese chives and lettuce caused by Botrytis cinerea was also controlled effectively in field tests by the application of Bacillus sp. AC-1 with control values of 79.7% and 72.8%, respectively. Spraying of the bacterial suspension inhibited development of powdery mildew of many crops such as cucumber, tobacco, melon, and rose effectively in greenhouse and field tests. The control efficacy of the bacterial suspension was almost same as that of Fenarimol used as a chemical standard. Further experiments for developing a commercial product from the antagonistic bacteria and for elucidating antagonistic mechanism against plant pathogenic fungi are in progress.

• The Plant Pathology Journal
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• 제25권3호
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• pp.220-224
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• 2009

The causal agents of bacterial blossom blight in kiwifruit were isolated from flowers displaying symptoms in Korea. The pathogens were characterized by biochemical and physiological tests, and identified on the basis of 16S rDNA and 16S-23S internal transcribed spacer (ITS) sequences. Pathogenicity tests demonstrated that the blossom blight of kiwifruit in Korea is caused by two pathogens, Pseudomonas syringae pv. syringae and P. fluorescens. Carbon source utilization and DNA-DNA hybridization experiments confirmed P. fluorescens as one of the causal agents of blossom blight of kiwifruit. P. syringae pv. syringae and P. fluorescens can be distinguished from each other by the symptoms they produce in flowers. P. syringae pv. syringae primarily affected the stamen, while P. fluorescens caused rotting of all internal tissues of buds or flowers.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.740-747
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• 2014

Bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. oryzae (Xoo) is a very serious disease in rice-growing regions of the world. In spite of their economic importance, there are no effective ways of protecting rice plants from this disease. Bacteriophages infecting Xoo affect the population dynamics of the pathogen and consequently the occurrence of the disease. In this study, we investigated the diversity, host range, and infectivity of Xoo phages, and their use as a bicontrol agent on BLB was tested. Among the 34 phages that were isolated from floodwater in paddy fields, 29 belonged to the Myoviridae family, which suggests that the dominant phage in the ecosystem was Myoviridae. The isolated phages were classified into two groups based on plaque size produced on the lawn of Xoo. In general, there was a negative relationship between plaque size and host range, and interestingly the phages having a narrow host range had low efficiency of infectivity. The deduced protein sequence analysis of htf genes indicated that the gene was not a determinant of host specificity. Although the difference in host range and infectivity depending on morphotype needs to be addressed, the results revealed deeper understanding of the interaction between the phages and Xoo strains in floodwater and damp soil environments. The phage mixtures reduced the occurrence of BLB when they were treated with skim milk. The results indicate that the Xoo phages could be used as an alternative control method to increase the control efficacy and reduce the use of agrochemicals.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.138-138
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• 2017

Agriculture is the most primitive civilized Activities of mankind but also the propellant of civilization development. Because it is the most basic material goods source of mankind. Among these materials rice is one of the most important part of these, we call them the substance of survival. From the beginning of the agricultural activities to the present we have experienced three industrial revolutions and are experiencing the Fourth Industrial Revolution. With the development of science and technology makes the efficiency of agricultural production is higher and higher, but compared with the original we are facing the same problem: natural disasters; pests and diseases; now also face the depletion of resources, environmental degradation and other issues. Therefore, improve and cultivate new crop varieties to make it better resistance and more production for better develop modern agriculture. It's very helpful for human social development. And also it is the responsibility and task of modern molecular breeding. In this study, I used bacterial leaf blight to find a better resistance gene to improve the resistance of rice. Frist Cultivate k3 of bacterial leaf blight, than inoculation by leaf clipping method (Kauffman,1973) in CNDH and SNDH population at 40days after rice transplanting. Check the lesion length by inoculation plants at 14days after inoculation, and record data for QTL analysis program. Than I get 4 intervals in 3 different chromosomal regions. I found these defense genes in the 4 intervals. So I used NCBI Justbio, Rapdb, etc. to finding these genes in physical map, than design primer for map base cloning. At last these defense genes will be employed in further research for introduction of the gene to the parental plant and rice breeding for solving food crisis.

• 방사선산업학회지
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• 제4권3호
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• pp.209-213
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• 2010

Bacterial blight is one of the most serious diseases of rice (Oryza sativa L.), and it has been known that Xanthomonas oryzae pv. oryzae (Xoo) causes this disease symptom. To develop resistance rice cultivars against Xoo, 3,000 lines of $M_3$ mutants, which were irradiated with gamma ray, were tested by 'scissor-dip method' primarily, and 191 putative resistant lines were selected. In $M_4$ generation, these lines were screened again with various ways such as measuring of symptom of bacterial blight in leaf, number of tiller, fresh weight, and phenotypic segregation ratio in next generation. Finally, six resistance lines were selected. RT-PCR analysis revealed that these lines displayed high level of R-genes such as Xa21, Pi36, and Pi-ta. These results indicate that mutations by gamma ray cause disruptions of regulatory signal transduction systems of these R-genes. Furthermore, these selected mutants could be useful for the development of rice cultivar resistant to Xoo.

• 미생물학회지
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• 제55권1호
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• pp.80-82
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• 2019

Pseudomonas syringae pv. syringae WSPS007 균주는 대한민국 경상북도 영주시 사과 과원에서 나타난 가지마름병 병징으로부터 2013년 분리되었다. 본 논문에서는 6,238,498 bp(59.04% G+C 함량)인 WSPS007 균주의 전체 염기서열을 보고한다. 전체 지놈은 5,379개의 코딩서열, 65개의 tRNA, 16개의 rRNA 유전자를 가지고 있다. 특히 WSPS007 균주의 전체 염기서열 분석은 냉해와 관련된 빙핵 활성 유전자 클러스터를 중심으로 분석을 수행하였으며, P. syringae pv. syringae 국외 대표 균주인 PssB728a와 유사한 빙핵활성 유전자 구성을 가지고 있는 것으로 나타났다. 따라서 본 논문에서의 염기서열 분석 결과를 바탕으로 경상북도 일원 사과 과원에서 동해로 추정되는 병원균의 원인을 규명하기 위한 기본 자료를 제공하는데 있어서 의의가 있다고 사료된다.

• The Plant Pathology Journal
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• 제39권4호
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• pp.409-416
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• 2023

Bacterial leaf blight of carrots caused by Xanthomonas hortorum pv. carotae (Xhc) is an important worldwide seed-borne disease. In 2012 and 2013, symptoms similar to bacterial leaf blight were found in carrot farms in Jeju Island, Korea. The phenotypic characteristics of the Korean isolation strains were similar to the type strain of Xhc. Pathogenicity showed symptoms on the 14th day after inoculation on carrot plants. Identification by genetic method was multi-position sequencing of the isolated strain JJ2001 was performed using four genes (danK, gyrB, fyuA, and rpoD). The isolated strain was confirmed to be most similar to Xhc M081. Furthermore, in order to analyze the genetic characteristics of the isolated strain, whole genome analysis was performed through the next-generation sequencing method. The draft genome size of JJ2001 is 5,443,372 bp, which contains 63.57% of G + C and has 4,547 open reading frames. Specifically, the classification of pathovar can be confirmed to be similar to that of the host lineage. Plant pathogenic factors and determinants of the majority of the secretion system are conserved in strain JJ2001. This genetic information enables detailed comparative analysis in the pathovar stage of pathogenic bacteria. Furthermore, these findings provide basic data for the distribution and diagnosis of Xanthomonas hortorum pv. carotae, a major plant pathogen that infects carrots in Korea.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2020년도 춘계학술대회
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• pp.49-49
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• 2020

Bacterial leaf blight (BLB), caused by X. oryzae pv. oryzae(Xoo), is one of the most destructive diseases of rice due to its high epidemic potential. Understanding BLB resistance at a genetic level is important to further improve the rice breeding that provides one of the best approaches to control BLB disease. In the present investigation, a total of 10,000 accessions of rice germplasm were tested to resistance degree of four Korean isolated races (K1, K2, K3 and K3a) of Xoo by bioassay and a diverse 268 accessions was selected to the genome-wide association study (GWAS) using high quality 34,724 SNPs to identify the associated with resistance loci. LOC_Os04g53160 of chromosome 4 was significantly associated with K1 race resistant. LOC_Os11g46230 and LOC_Os11g47150 of chromosome 11 were highly associated with K2 and K3 races as 23.7 and 27.4 of -log(P) value, but K3a resistant loci was weakly associated at LOC_Os03g55270 of chromosome 3. The results of the GWAS validate known gene of BLB resistant and identified novel loci of R genes that provide useful targets for further investigation to help the breeding system and identified gene and QTL provide valuable sources for further functional characterization.

• The Plant Pathology Journal
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• 제40권2호
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• pp.160-170
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• 2024

Erwinia amylovora is a plant pathogen that causes fire blight on apples and pears. Bacteriophages, which are viruses that selectively infect specific species of bacteria and are harmless to animal cells, have been considered as biological control agents for the prevention of bacterial pathogens. In this study, we aimed to use bacteriophages that infect E. amylovora as biocontrol agents against fire blight. We isolated bacteriophages Fifi044 and Fifi318 infecting E. amylovora, and characterized their morphology, plaque form, and genetic diversity to use as cocktails for disease control. The stabilities of the two phages were investigated at various temperatures and pH values and under sunlight, and long-term storage experiment was conducted for a year. To evaluate whether the two phages were suitable for use in cocktail form, growth curves of E. amylovora were prepared after treating the bacterial cells with single phages and a phage cocktail. In addition, a disease control test was conducted using immature apples and in vitro cultured apple plantlets to determine the biocontrol effects of the phage cocktail. The two phages were morphologically and genetically different, and highly stable up to 50℃ and pH value from 4 to 10. The phages showed synergistic effect when used as a cocktail in the inhibition of host bacterial growth and the disease control. This study demonstrated that the potential of the phage cocktail as a biocontrol agent for commercial use.

• Journal of Plant Biotechnology
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• 제44권2호
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• pp.149-155
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• 2017

벼는 중요한 식량작물이며 지속적으로 벼흰잎마름병균, 도열병균, 잎집무늬마름병균, 바이러스 등 여러 병원균에 의해 수확량이 영향을 받고 있다. 이들 중 Xanthomonas oryzae pv. oryzae (Xoo)에 의해 유발되는 벼흰잎마름병은 세계 벼 재배지역에 발병하여 막대한 피해를 주고 있어 문제가 되고 있다. 따라서 생물적/비생물적 스트레스 저항성에 관여한다고 알려져 있는 식물 특이 전사인자 중의 하나인 NAC(NAM, ATAF, and CUC) 전사인자를 이용하여 벼의 벼흰잎마름병에 대한 저항성을 증진시키고자 하였다. 본 연구에서는 벼에서 NAC 전사인자 중 하나인 OsNAC58 유전자를 분리해 냈으며 아미노산 서열을 바탕으로 분석해 본 결과이 유전자는 5개의 NAC전사인자 group 중에서도 stress와 많은 관련이 있다고 알려진 group III에 속하였다. 또한 세포 내 위치를 확인하기 위해 GFP와 융합한 단백질을 이용해 조사해 본 세포 내에서도 핵에 위치하는 것으로 조사되었다. OsNAC58 유전자의 생물학적 기능 분석을 위해 이 유전자를 과발현시킨 벼 형질전환체를 만들었다. 동진벼를 기준으로 보다 발현이 높은 13개 계통을 선발하였으며, 이들 계통에 벼흰잎마름병균을 접종하여 병저항성을 검정한 결과 동진벼에 비해 벼흰잎마름병에 대한 저항성이 크게 증대함을 보였다. 이것은 벼의 OsNAC58 유전자가 벼흰잎마름병균 침입 시 숙주인 벼 핵 내에서 벼의 병저항성 기작을 조절하여 나타난 결과로 추정된다.