• Molecules and Cells
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• v.27 no.5
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• pp.563-570
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• 2009

We previously isolated the OsCBT gene, which encodes a calmodulin (CaM)-binding protein, from a rice expression library constructed from fungal elicitor-treated rice suspension cells. In order to understand the function of OsCBT in rice, we isolated and characterized a T-DNA insertion mutant allele named oscbt-1. The oscbt-1 mutant exhibits reduced levels of OsCBT transcripts and no significant morphological changes compared to wild-type plant although the growth of the mutant is stunted. However, oscbt-1 mutants showed significant resistance to two major rice pathogens. The growth of the rice blast fungus Magnaporthe grisea, as well as the bacterial pathogen Xanthomonas oryzae pv. oryzae was significantly suppressed in oscbt-1 plants. Histochemical analysis indicated that the hypersensitive-response was induced in the oscbt-1 mutant in response to compatible strains of fungal pathogens. OsCBT expression was induced upon challenge with fungal elicitor. We also observed significant increase in the level of pathogenesis-related genes in the oscbt-1 mutant even under pathogen-free condition. Taken together, the results support an idea that OsCBT might act as a negative regulator on plant defense.

• 한국균학회소식:학술대회논문집
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• 2014.05a
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• pp.37-37
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• 2014

Glomerella leaf spot pathogens can infect apple leaves, causing extensive necrosis and premature defoliation, as well as necrotic spots on fruit. In recent years, the disease has been reported with increasing frequency in China, and appears to be spreading rapidly in some apple-producing areas. In this study, fungal isolates from diseased apples leaves collected in Henan and Shaanxi provinces were analyzed based on morphology, cultural characters, pathogenicity and molecular phylogenetics. It was found that Glomerella leaf spot of apple was caused by two pathogens, Colletotrichum fructicola and C. aenigma. Pathogenicity tests showed that C. fructicola and C. aenigma could infect apple leaves of cultivar Golden Delicious, as well as Gala, Qinguan, Pink Lady, Pacific Rose, Golden Century and Honeycrisp, all of which include Golden Delicious in their parentage. In wound inoculation experiments, C. fructicola and C. aenigma were pathogenic to fruit of Gala, Qinguan, Golden Delicious, Pacific Rose, Starkrimson and Fuji. With non-wounded fruit, C. fructicola was pathogenic to Gala and Golden Delicious, and C. aenigma was pathogenic to Gala. It is concluded that the two pathogens could be differentiated according to pathogenicity to leaves and fruits of different apple cultivars.

• Korean Journal of Veterinary Research
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• v.57 no.4
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• pp.209-214
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• 2017

Wild raccoon dogs (Nyctereutes procyonoides koreensis) may play a role transmitting several pathogens to humans and pet animals. Information concerning the incidence of rabies, canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus type 2 (CAdV-2), canine parainfluenza virus type 5 (CPIV-5), and canine herpesvirus (CHV) is needed in wild raccoon dogs. In total, 62 brain samples of raccoon dogs were examined for rabies virus (RABV) and CDV, and 49 lung samples were screened for CDV, CAdV-2, CPIV-5, and CHV. No RABV, CAdV-2, CPIV-5, or CHV was identified, but nine CDV antigens (8.1%, 9/111) were detected. Moreover, 174 serum samples from wild raccoon dogs were screened for antibodies against the five major viral pathogens. The overall sero-surveillance against CDV, CPV, CAdV-2, CPIV-5, and CHV in wild raccoon dogs was 60.3%, 52.9%, 59.8%, 23.6%, and 10.3%, respectively. Comparisons of the sero-surveillance of the five pathogens showed that raccoon dogs of Gyeonggi province have slightly higher sero-positive rates against CDV, CPV, and CHV than those of Gangwon province. These results indicate high incidences of CDV, CPV, and CAdV-2 in wild raccoon dogs of two Korean provinces and a latent risk of pathogen transmission to companion and domestic animals.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2000.10a
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• pp.22.1-22
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• 2000

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.10a
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• pp.56.2-56
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• 1999

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.654-660
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• 1998

Colletotrichum gloeosporioides and Glomerella cingulata are the most important pathogens causing anthracnose which may reduce the stand rate and yield on wide kinds of plants including strawberry. Average occurrence rate of anthracnose is 36.9% on major strawberry cropping areas in Korea. We newly found that C. gloeosporioides which does not forming a sexual stage, infects strawberry and differs in some characteristics concerning virulence, cultural and morphological properties to G. cingulata which has a sexual stage. C. gloeosporioides was mainly isolated from the crown with 35.2% rate, while G. cingulata was largely isolated from petiole, runner with 40.9% rate in infected strawberry plants. These two pathogens showed significant differences in cultural characteristics such as perfect stage formation, temperature response as well as benomyl resistance. It was demonstrated that C. gloeosporioides has significantly stronger pathogenicity than G. cingulata in pathogenicity test carried on strawberry plants to various strawberry cultivars. Akihime, Akaneko and Nyoho forcing cultured strawberry cultivars, considered to be susceptible, while semiforcing cultured cultivars, such as Suhong and Holowase, were shown resistant to both pathogens. In non-wound inoculation, C. gloeosporioides was shown pathogenicity on the apple fruit, but G. cingulata could not infect it.

• Journal of Microbiology and Biotechnology
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• v.22 no.5
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• pp.585-591
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• 2012

The antagonistic effect of Trichoderma harzianum on a range of seed-borne fungal pathogens of wheat (viz. Fusarium graminearum, Bipolaris sorokiniana, Aspergillus spp., and Penicillium spp.) was assessed. The potential of T. harzianum as a biocontrol agent was tested in vitro and under field conditions. Coculture of the pathogens and Trichoderma under laboratory conditions clearly showed dominance of T. harzianum. Under natural conditions, biocontrol effects were also obtained against the test fungi. One month after sowing, field emergence (plant stand) was increased by 15.93% over that obtained with the control treatment, and seedling infection was reduced significantly. Leaf blight severity was decreased from 22 to 11 at the heading stage, 35 to 31 at the flowering stage, and 86 to 74 at the grain filling stage. At harvest, the number of tillers per plant was increased by 50%, the yield was increased by 31.58%, and the 1,000-seed weight was increased by 21%.

• The Plant Pathology Journal
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• v.23 no.3
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• pp.223-225
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• 2007

Many plant growth-promoting rhizobacteria (PGPRs) have been known for beneficial effects on plants including biological control of soilborne pathogens, induced systemic resistance to plant pathogens, phytohormone production, and improvement of nutrient and water uptake of plants. We developed a simple and rapid method for screening potential PGPR, especially phytohormone producing rhizobacteria, or for analyzing their functions in plant growth using cucumber seedling cuttings. Surface-sterilized cucumber seeds were grown in a plastic pot containing steamed vermiculite. After 7 days of cultivation, the upper part 2 cm in length of cucumber seedling, was cut and used as cucumber cuttings. The base of cutting stem was then dipped in a microcentrifuge tube containing 1.5ml of a bacterial suspension and incubated at $25^{\circ}C$ with a fluorescent light for 10 days. Number and length of developed adventitious roots from cucumber cuttings were examined. The seedling cuttings showed various responses to the isolates tested. Some isolates resulted in withering at the day of examination or in reduced number of roots developed. Several isolates stimulated initial development of adventitious roots showing more adventitious root hair number than that of untreated cuttings, while some isolate had more adventitious root hair number and longer adventitious roots than that of untreated control. Similar results were obtained from the trial with rose cuttings. Our results suggest that this bioassay method may provide a useful way for differentiating PGPR's functions involved in the development of root system.

• Journal of Ginseng Research
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• v.22 no.4
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• pp.229-236
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• 1998

The incidence of fungi and their possible contribution to low vigour were examined in a collection of ginseng (Panax quiquefolius) seed from Ontario. When examined after one winter of stratification in the field and storage at 4f for five months in the laboratory, the collection exhibited low vigour (plant stand 16.7% of seeding rate six weeks after seeding) and high incidence (94%) of discolored or soft seed. Fungi isolated (and incidence) from 1,304 endosperm halves recovered from surface-sterilized seed were, in order of abundance, Fusarium rostrum (22.2%), Chaetomium crispuum (14.3%), Funriud oxysporum (9.0%), Fusarium sdani (9.0%), iwmor sp. (8.4%), Alternaria sp. (8.1%), Zowieua lucotricha (7.8%), Cylindruarpn sp. (0.9%), Fusarium avenacmm (0.9%), and Vdudla iliata (0.4%). Most of these fungi, including known and potential pathogens of ginseng (species of Alerraria, Cylindrocarpon, Fusarium, and Trichodirma), were associated with both healthy and diseased seed. Application of Benlate (benomyl), Thiram (thiram), or UBI-2584 (tebuconazole) to seed caused slight to pronounced reduction in emergence and did not significantly affect plant stand six weeks after seeding. The study demonstrated the high level of infection by fungi, including known and potential pathogens of the cry, in an arbitrary collection of ginseng seed from commercial sources, and the phytotoxicity of the fungicides tested when applied to moist stratified seed. The lack of efficacy of the fungicides precluded determination of the contribution of seedborne fungi to low vigour of the seed.

• The Plant Pathology Journal
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• v.25 no.3
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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.