• The Plant Pathology Journal
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• v.37 no.1
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• pp.79-85
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• 2021

Chemical and biological agents were evaluated to inhibit Colletotrichum fructicola, Phytophthora cactorum, and Lasiodiplodia theobromae causing strawberry diseases. Mycelial growths of C. fructicola were gradually arrested by increasing concentrations of fungicides pyraclostrobin and iminoctadine tris (albesilate). P. cactorum and L. theobromae were more sensitive to pyraclostrobin compared to C. fructicola, but iminoctadine tris (albesilate) was not or less effective to limit P. cactorum or L. theobromae, respectively. Bacillus siamensis H30-3 was antagonistic against the three pathogens by diffusible as well as volatile molecules, and evidently reduced aerial mycelial formation of P. cactorum. B. siamensis H30-3 growth was declined by at least 0.025 mg/ml of pyraclostrobin. The two fungicides additively inhibited mycelial growths of C. fructicola, but not of P. cactorum and L. theobromae. B. siamensis H30-3 volatiles led to less growth of C. fructicola than one reduced by the fungicides. Taken together, in vitro antimicrobial activities of the two fungicides together with or without B. siamensis H30-3 volatiles may be cautiously incorporated into integrated management of strawberry diseases dependent on causal pathogens.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.178-184
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• 2010

Four major diseases of chili pepper including two fungal diseases, anthracnose (Colletotrichum acutatum) and Phytophthora blight (Phytophthora capsici), and two bacterial diseases, bacterial wilt (Ralstonia solanacearum) and bacterial spot (Xanthomonas campestris pv. vesicatoria), were investigated under future climate-change condition treatments in growth chambers. Treatments with elevated $CO_2$ and temperature were maintained at $720ppm{\pm}20ppm$ $CO_2$ and $30^{\circ}C{\pm}0.5^{\circ}C$, whereas ambient conditions were maintained at $420ppm{\pm}20ppm$ $CO_2$ and $25^{\circ}C{\pm}0.5^{\circ}C$. Pepper seedlings or fruits were infected with each pathogen, and then the disease progress was evaluated in the growth chambers. According to paired t-test analyses, bacterial wilt and spot diseases significantly increased by 24% (p=0.008) and 25% (p=0.016), respectively, with elevated $CO_2$ and temperature conditions. On the other hand, neither Phytophthora blight (p=0.906) nor anthracnose (p=0.125) was statistically significant. The elevated $CO_2$ and temperature accelerated the progress of bacterial wilt by two days and bacterial spot by one day compared to the ambient treatment. Temperature regime studies of the diseases without changes in $CO_2$ confirmed that the accelerated bacterial disease progress was mainly due to the increased temperature rather than the elevated $CO_2$ conditions.

• Korean Journal Plant Pathology
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• v.13 no.1
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• pp.57-62
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• 1997

This experiment was conducted to test the control effect of methanol extracts of 10 medicinal plants on apple storage diseases caused by Botryosphaeria berengeriana, Glomerella cingulata and Penicillium expansum. Out of the 10 medicinal plants, methanol extracts of Coptis japonica and Anemarrhena asphodeloides inhibited effectively the mycelial growth of B. berengeriana, G. cingulata and P. expansum in vitro, for which the inhibition ratios of the two plant extracts were 100.0% and 89.3%, 73.7% and 94.1%, and 100.0% and 51.6%, respectively. Spore germination of the three fungi was inhibited 100% only by C. japonica extract, but only P. expansum was inhibited 100% by A. asphodeloides extract. No lesion was formed y the fungi at 5$^{\circ}C$ up to 2 weeks after inoculation. Lesion sizes produced by the three fungi at the temperature ranges of 1$0^{\circ}C$ to $25^{\circ}C$ and infection of B. berengeriana and G. cingulata were inhibited by C. japonica extract, but not by A. asphodeloides extract, while no lesion was formed by the fungi at 5$^{\circ}C$. Infections of the fungi on apples were somewhat stimulated by A. asphodeloides extract.

• The Plant Pathology Journal
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• v.28 no.2
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• pp.156-163
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• 2012

Stem rots caused by Rhizoctonia solani and Sclerotinia sclerotiorum have been known as devastating diseases in balloon flower plants. Antifungal activities of four fungicides, azoxystrobin, polyoxin B, trifloxystrobin and validamycin A were evaluated in vitro, showing effective suppression with mycelial growth of the fungal isolates on PDA media. Efficacies of the four fungicides were also demonstrated in stem tissues of balloon flower plants against R. solani and S. sclerotiorum. A commercially available Bacillus subtilis strain Y1336 was tested in terms of antagonistic biological control of stem rot disease of balloon flower plants. The bacterial strain revealed its antifungal activities against R. solani and S. sclerotiorum demonstrated by dual culture tests using paper discs and two plant pathogenic fungi on PDA media, as well as by plant inoculation assay, indicating that this antagonistic bacterial strain can be incorporated into disease management program for balloon flower stem rot diseases together with the four chemical fungicides.

• The Plant Pathology Journal
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• v.29 no.3
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• pp.344-349
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• 2013

Intraspecific variation in morphometry of pine wood nematodes Bursaphelenchus xylophilus and B. mucronatus in relation to geographical locations in South Korea was investigated using morphometric characters (body length, a, b and c ratio, stylet length, and spicule length for a male nematode and V (%) value for a female nematode). B. xylophilus was isolated from Pinus thunbergii in Jinju (1998), Ulsan (2000), Yangsan (2000), Mokpo (2001) and Jeju (2004), and from P. densiflora in Gumi (2001). B. mucronatus was isolated from P. thunbergii in Jinju (1991) and from P. densiflora in Milyang (2001). The body length of male and female B. xylophilus had the highest coefficient of variability and showed significant differences among geographical locations. The V (%) value for female B. xylophilus showed the lowest coefficient of variability, changing little with geographical area and host plant. All morphometric characters in B. mucronatus except for stylet length and female body length showed no significant differences between locations or hosts, suggesting they may not be affected by geographical area or host plant.

• The Plant Pathology Journal
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• v.23 no.1
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• pp.26-30
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• 2007

Phosphorous acid is known to effectively control various Oomycetes diseases. The phosphoric acid moves upward and downward through the xylem and phloem in plants. The sustainable forms of the slow releasing chemical in rhizosphere would be ideal to be up-taken by plants. Therefore, we developed a new system for phosphorous acid formulation using a carrier coated with polysaccharides. When the product was applied in rhizosphere, the adequate amount of phosphorous acid was consistently released up to 4 weeks in rhizosphere soils. While soil drenching with phosphorous acid at 1,000 ${\mu}g/ml$ and metalaxyl at 150 ${\mu}g/ml$ were not effective to control pepper Phytophthora blight for 4 weeks, direct application of our formulation product around basal stem of pepper plants resulted in excellent disease control effect against Phytophthora blight over 4 weeks. The application of 4 g of our product per plant was optimum to control the disease, and 8 g product/plant did not cause phytotoxicity. Based on the results, we conclude that the applications of the formulation product once or twice during cropping season can control Phytophthora diseases on various crops.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.529-542
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• 2017

Control of plant diseases is largely dependent on use of agrochemicals. However, there are widening gaps between our knowledge on plant diseases gained from genetic/mechanistic studies and rapid translation of the knowledge into target-oriented development of effective agrochemicals. Here we propose that the time is ripe for computer-aided drug discovery/design (CADD) in molecular plant pathology. CADD has played a pivotal role in development of medically important molecules over the last three decades. Now, explosive increase in information on genome sequences and three dimensional structures of biological molecules, in combination with advances in computational and informational technologies, opens up exciting possibilities for application of CADD in discovery and development of agrochemicals. In this review, we outline two categories of the drug discovery strategies: structure- and ligand-based CADD, and relevant computational approaches that are being employed in modern drug discovery. In order to help readers to dive into CADD, we explain concepts of homology modelling, molecular docking, virtual screening, and de novo ligand design in structure-based CADD, and pharmacophore modelling, ligand-based virtual screening, quantitative structure activity relationship modelling and de novo ligand design for ligand-based CADD. We also provide the important resources available to carry out CADD. Finally, we present a case study showing how CADD approach can be implemented in reality for identification of potent chemical compounds against the important plant pathogens, Pseudomonas syringae and Colletotrichum gloeosporioides.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.434-434
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• 2005

• Asian Journal of Innovation and Policy
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• v.10 no.1
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• pp.108-131
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• 2021

The increase of international trade across countries and borders results in increased risks associated with the inflow of new pests and diseases. These risks are likely to be increased more rapidly due to climate change. Some countries implement strict regulations on imports to prevent these risks and protect biosecurity, food safety, and public health. However, the problems arise when the diseases and pests are found in a country where their economic structure largely depends on agricultural exports and cause ripple effects on other industries and ecosystems. Therefore, establishing an effective quarantine system is essential to protect and recover from the damage caused by non-native diseases and pests. This study's objectives are 1) analyzing the agricultural policies relate to the quarantine system on diseases and pests in Korea, 2) evaluating the Korea plant quarantine system's value, and 3) simulating plant quarantine policy strategies. We estimated the Korean quarantine system's benefits on diseases and pests to reach these objectives. The benefits are measured with a willingness to pay from respondents surveyed by the contingent valuation method (CVM). The CVM approach directly asks people how much they would willingly pay for food security. Finally, the Korean quarantine system's values are simulated with several policy scenarios and different scales of infection at the regional level. The results of this study can deliver policy implications on the quarantine system innovation in developing countries including Asia.

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1628-1634
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• 2009

Small heat shock proteins (sHSPs) function as molecular chaperones that protect cells against environmental stresses. In the present study, the genes of hsp17.6 and hsp17.7, cytosolic class I sHSPs, were cloned from a tropical plant, Ageratina adenophorum. Their C-terminal domains were highly conserved with those of sHSPs from other plants, indicating the importance of the C-terminal domains for the structure and activity of sHSPs. The recombinant HSP17.6 and HSP17.7 were applied to determine their chaperone function. In vitro, HSP17.6 and HSP17.7 actively participated in the refolding of the model substrate citrate synthase (CS) and effectively prevented the thermal aggregation of CS at $45^{\circ}C$ and the irreversible inactivation of CS at $38^{\circ}C$ at stoichiometric levels. The prior presence of HSP17.7 was assumed to suppress the thermal aggregation of the model substrate CS. Therefore, this report confirms the chaperone activity of HSP17.6 and HSP17.7 and their potential as a protectant for active proteins.