• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.779-782
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• 2006

• The Plant Pathology Journal
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• v.24 no.3
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• pp.283-288
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• 2008

Plant leaf surface is an important niche for diverse epiphytic microbes, including bacteria and fungi. Plant leaf surface plays a critical frontline defense against pathogen infections. The objective of our study was to evaluate the effectiveness of a starch-based super-absorbent polymer(SAP) combination, which enhances water potential and nutrient availability to plant leaves. We evaluated the effect of SAP on the maintenance of bacterial populations. In order to monitor bacterial populations in situ, a SAP mixture containing Pseudomonas syringae pv. tabaci that expressed recombinant green fluorescent protein(GFPuv) was spray-challenged onto whole leaves of Nicotiana benthamiana. The SAP combination treatment enhanced bacterial robustness, as indicated by disease severity and incidence. Unexpectedly, bacterial numbers were not significantly different between leaves treated with the SAP combination and those treated with water alone. Furthermore, young leaves treated with the SAP combination had more severe symptoms and a greater number of bacterial spots caused by primary and secondary infections compared to young leaves treated with the water control. In contrast, bacterial cell numbers did not statistically differ between the two groups, which indicated that measurement of viable GFP-based bacterial spots may provide a more sensitive methodology for assessing virulence of bacterial pathogens than methods that require dilution plating following maceration of bacterial-inoculated leaf tissue. Our study suggests that the SAP combination successfully increased bacterial aggressiveness, which could either be used to promote the ability of biological agents to control weedy plants or increase the robustness of saprophytic epiphytes against competition from potentially harmful microbes.

• Korean Journal of Microbiology
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• v.15 no.2
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• pp.77-84
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• 1977

The yeast population on 14 species of seaweeds and in water estimated by cultural mothods over a 5-month period in south-west in Korea, Nine species of yeasts, comprising unidentified one, and one of yeast-like fungi were identified. Fifty phycase were attributed to the difference of cultural method between the present work and earlier repoeters and, to some exent, the higher number of Rhodotorula glutinis which had a prior adaptation to the release of inhibitory polyphenolic materials. Although, to what extent, all division of algae showed a similar variation in yeast population, correlated with month, the rapid decrease of yeast population in August seems to be the cause of exposure of heat irradiation in this month. The cultural estimate of per se fltration without double filter and one of unidentified species are discussed.

• The Plant Pathology Journal
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• v.20 no.4
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• pp.247-251
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• 2004

We developed a polyclonal antibody (PAh) based- ELISA system to accurately and rapidly monitor inocula on plant surface before onset of anthracnose. Titer of mouse antisera against conidia of Colletotrichum gloeosporioides was determined by using indirect ELISA. It was high enough to be detectable up to ${\times}$ 12,800 dilutions. Absorbance readings exceeded (1.5even at a 10$^{-5}$ dilution. Sensitivity of PAb was precise enough to detect spore concentration as low as 50 conidia/well by indirect ELISA. PAb1 and PAb2 proved to be very sensitive and highly specific to the target pathogen, C. gloeosporioides, apparently discriminating other unrelated pathogens, or epiphytes. Absorbance values for original isolate exceeded 1.0, but no reaction was detected with other isolates, except three other anthracnose fungi: C. gloeosporioides (pepper strain), Glomerella cingulata (apple strain) and C. lagenarium. Our data suggest that PAb1 and PAb2 bind with the protein epitope that partially contains residues of amino acid, arginine, and Iysine. This kit fulfills the require-ments for detecting inoculums before infection and during onset of anthracnose on sweet persimmon.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.133.1-133
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• 2003

Gummy stem blight, caused by Didymella bryoniae occurs exclusively on cucurbits. This fungus has been known not to produce its pycnidium in vitro unless irradiated. Through this study, we optimized cultural conditions for mass-production of pycnidiospore by Metal Halide Lamp irradiation. In brief, the mycelial was cultured at $26^{\circ}C$ on PDA, for 2 days under the darkness, and then the plate was illuminated with MH lamp continuously for 3-4 days at $26^{\circ}C$, a great number of pycnidia was simultaneously formed. Thus produced pycnidiospores were used as immunogen. From fusions of myeloma cell (v-653) with splenocytes from immunifed mice were car ried out. And, two hybridoma cell lines that recognized the immunogen Didymella bryoniae were obtained. One Monoclonal Antibody, Db1, recognized the supernatant and the other monoclonal antibody, Db15, recognized the spore. Two clones were selected which were used to produce ascite fluid two MAb Db1 and Db15, were immunotyped and identified as IgG1 and IgG2b, respectively. Titer of MAb Db1 and MAb Db15 was measured absorbance exceeded 0.5 even at a $10^{-5}$ dilution. The MAbs reacted positively with Didymella bryoniae but none reacted with other of fungi and CMV, CGMMV Sensitivity of MAb was precise enough to detect spore concentration as low as $10^{3}$ well by indirect ELISA characterization of the MAb Db1, Db15 antigen by heat and protease treatments show that the epitope recognized by the MAb Bb1, Db15 were a glycoprotein.

• The Plant Pathology Journal
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• v.17 no.3
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• pp.141-148
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• 2001

Postharvest decay of onion bulbs was examined by inspecting the commercial packages in the market or in storage. Bulb rot incidence was unexpectedly high, and onion bulbs with 1st quality grade were rotten most severely by 51%, followed by 32% for 2nd and 21% for 3rd grades. This indicates that larger bulbs had higher incidences of bulb rots. Major pathogens associated with basal and neck rots were Fusarium oxysporum and Aspergillus sp. or Botrytis allii, respectively, of which basal rot was most prevalent and damaging during storage. Among the epiphytic microorgani는 from onion plants, several Bacillus and Paenibacillus spp. and previously selected Pseudomonas putida and Trichoderma harzianum had inhibitory efficacy against bulb rot pathogens. Among these B. amyloliquefaciens BL-3, Paenibacillus polymyxa BL-4, and P. putida Cha 94 were highly inhibitory to conidial germination of F. oxysporum and B. allii. P. putida Cha 94, B. amyloliquefaciens BL-3, P. polymyxa BL-4, and T. harzianum TM were applied in the rhizoplane of onion at transplanting. Initially antagonist populations decreased rapidly during the first one month. However, among these antagonists, rhizoplane population densities of BL-3, Cha 94, and TM were consistently high thereafter, maintaining about 10$^4$-10$^{5}$ cells or spores per gram of onion root up to harvest time. The other bacterial antagonist BL-4 survived only for two months. TM was the most effective biocontrol agent against basal rot, with the number of rotten bulbs recorded at 4%, while that of the control was 16%. Cha 94 was effective for the first 20 days, but basal rot increased thereafter and had about the same control efficacy as that of BL-3 and BL-4. When the antagonists were applied to the topping areas of onion bulbs at harvest, TM was the most effective in protecting the stored onion bulbs from neck rotting. The second effective antagonist was BL-3. TM and BL-3 completely suppressed the neck rot in another test, suggesting that biocontrol of postharvest decay of onion using these microorganisms either at the time of transplanting or at harvesting may be promising.