• The Plant Pathology Journal
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• v.35 no.5
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• pp.425-436
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• 2019

Botrytis cinerea, a major phytopathogenic fungus, has been reported to infect more than 200 crop species worldwide, and it causes massive losses in yield. The aim of this study was to evaluate the inhibitory abilities and effects of Bacillus amyloliquefaciens RS-25, Bacillus licheniformis MG-4, Bacillus subtilis Z-14, and Bacillus subtilis Pnf-4 and their culture filtrates and extracts against the gray mold caused by B. cinerea on postharvest tomato, strawberry, and grapefruit. The results revealed that the cells of Z-14, culture filtrate of RS-25, and cells of Z-14 showed the strongest biocontrol activity against the gray mold on the strawberry, grape, and tomato fruit, respectively. All the strains produced volatile organic compounds (VOCs), and the VOCs of Pnf-4 displayed the highest inhibition values. Based on headspace solid-phase microextraction in combination with gas chromatography-mass spectrometry, esters accounted for the largest percentage of the VOCs produced by RS-25, MG-4, Z-14, and Pnf-4 (36.80%, 29.58%, 30.78%, and 36.26%, respectively). All the strains showed potent cellulase and protease activities, but no chitinase activity. RS-25, Z-14, and MG-4, but not Pnf-4, grew on chrome azurol S agar, and an orange halo was formed around the colonies. All the strains showed biofilm formation, fruit colonization, and lipopeptide production, which may be the main modes of action of the antagonists against B. cinerea on the fruit. This study provides the basis for developing natural biocontrol agents against the gray mold caused by B. cinerea on postharvest fruit.

• Journal of agriculture & life science
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• v.46 no.6
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• pp.67-74
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• 2012

A study was conducted to examine the effect of precooling and storage temperatures on the storage life of 'Maehyang' strawberry for export. Fruits at a 80% ripe stage were harvested from a commercial greenhouse in Gyeongsangnamdo Jinju on January 11, 2011. Fruits were precooled at 0, 2, $4^{\circ}C$ for 2-5 hours, and then transported for about 30 minutes. And stored in set chamber at 4, 8, $10^{\circ}C$, immediately. Fruits were examined for their changes in weight, hardness, Hunter color values, soluble solid content (SSC), acidity, and incidence of gray mold (Botrytis cinerea) during storage. The fresh weight decreased during storage at all temperatures. Especially, strawberry treated the lowest precooling and storage temperatures was the greatest in quality. The hardness was drastically decreased in precooled at $4^{\circ}C$ and stored at $10^{\circ}C$ after storage 10 days. SSC was the greatest when strawberry stored at the lowest temperature. Acidity increased during storage at all temperatures. But in the last day after storage, the strawberry of precooled at $4^{\circ}C$ and stored at $10^{\circ}C$ was the highest as 0.7%. Gray mold was the greatest at $10^{\circ}C$ storage temperature. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $0^{\circ}C$ and storage at $4^{\circ}C$.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.90.2-91
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• 2003

In commercial greenhouses, senescent flower petals or flowers of vegetables such as tomato, strawberry, hot pepper and zucchini squash were blighted to be removed from fruits within five days after spraying of Trichoderma harzianum YC459 (TORY), a biocontrol agent for the gray mold rot of vegetables caused by B. cinerea The mechanism for selective colonization of senescent floral tissues by T. harzianum YC459 was elucidated using fresh and senescent (Hays and 14days after flowering, respectively) floral tissues of zucchini squash (Cucurbita moschata Duchesne). The spores of T. hrzianum YC459 were produced more on agar and liquid culture media supplemented with 5％ dry powder of senescent floral tissues than fresh tissues during 15days. Mycelial growth was also much better in the media with senescent tissues than with fresh tissues. Enzyme activities of amylase, polygalacturonase and cellulase in the liquid media which might be involved in the colonization of tissues by T. harzianum YC459 were compared. The activities of three enzymes were much higher in the media with senescent floral tissues than with fresh floral tissues reaching to the maximum during 9 to 12days of incubation. Based on the results, the removal of senescent floral tissues, a possible inoculum source of the pathogen, may be another mechanism for biocontrol of gray mold rot of vegetables by T. harzianum YC459.

• Mycobiology
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• v.46 no.1
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• pp.33-46
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• 2018

Gray mold (Botrytis cinerea) is one of the most common diseases of strawberries (Fragaria${\times}$ananassa Duchesne) worldwide. Although many chemical fungicides are used for controlling the growth of B. cinerea, the risk of the fungus developing chemical resistance together with consumer demand for reducing the use of chemical fungicides have necessitated an alternative method to control this pathogen. Various naturally occurring microbes aggressively attack plant pathogens and benefit plants by suppressing diseases; these microbes are referred to as biocontrol agents. However, screening of potent biocontrol agents is essential for their further development and commercialization. In this study, 24 strains of yeast with antagonistic ability against gray mold were isolated, and the antifungal activity of the volatile and diffusible metabolites was evaluated. Putative mechanisms of action associated with the biocontrol capacity of yeast strains against B. cinerea were studied through in vitro and in vivo assays. The volatile organic compounds produced by the Galactomyces candidum JYC1146 could be useful in the biological control of plant pathogens and therefore are potential alternative fungicides with low environmental impact.

• Mycobiology
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• v.41 no.2
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• pp.108-111
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• 2013

The use of a microorganism, or its secretions, to prevent plant disease offers an attractive alternative or supplement to synthetic fungicides for the management of plant disease without the negative effects of chemical control mechanisms. During a screening for microorganisms with the potential to be used as microbial fungicides, Bacillus sp. BS061 was isolated from a plant leaf. The strain BS061 potently inhibited the mycelial growth of Botrytis cinerea, and significantly reduced disease incidence of powdery mildew in cucumber and strawberry. We also found that the culture filtrate of BS061 inhibited the mycelial growth of various plant pathogens.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.432-438
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• 2013

A study was conducted to examine the effect of maturity and precooling ($60%/0^{\circ}C$ and $80%/4^{\circ}C$), and light illumination on the storage life of 'Maehyang' strawberry meant for export. Fruits at 60% and 80% ripened stage were harvested from a commercial greenhouse in Jinju on April 3, 2012. Harvested fruits were transported to the precooling system within 30 minutes. Transported fruits were precooled the $4^{\circ}C$ for 2 hours and $0^{\circ}C$ for 5 hours by a forced draft cooling system, and then stored at $6^{\circ}C$. During the storage, the fruits were examined for their changes in hardness, soluble solid content, quality grade, acidity, Hunter value, weight loss, and the incidence of gray mold (Botrytis cinerea) at an interval of two days from April 5 to April 17. Hardness was decreased until 7th days and it was changed to increase at 9th days. Treatment of 60% maturity, $0^{\circ}C$ precooling and no light illumination of strawberry were shown the highest value in freshness. The soluble solid content harvested in 80% maturity strawberry was higher than 60% maturity strawberry until the third day. Quality grade decreased rapidly in 80% maturity stage with light illumination strawberry in comparison to the 60% maturity stage of strawberry. Hunter value 'L' and 'a' showed a rapid change in 60% maturity stage of strawberry. Weight loss decreased rapidly in 80% maturity, $0^{\circ}C$ precooling, and no light illumination of strawberry treatments. Gray mold incidence was found the most at 60% maturity, $4^{\circ}C$ precooling, and light illumination of strawberry. The results from our study indicate that effectiveness for keeping the freshness of strawberry was best achieved by harvesting in low maturity, precooling at $0^{\circ}C$, and with no light illumination.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.170-177
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• 2010

Bacillus licheniformis N1, previously developed as a biofungicide formulation N1E to control gray mold disease of plants, was investigated to study the bacterial traits that may be involved in its biological control activity. Two N1E based formulations, bacterial cell based formulation PN1E and culture supernatant based formulation SN1E, were evaluated for disease control activity against gray mold disease of tomato and strawberry plants. Neither PN1E nor SN1E was as effective as the original formulation N1E. Fractionation of antifungal compounds from the bacterial culture supernatant of B. licheniformis N1 indicated that two different cyclic lipopeptides were responsible for the antimicrobial activity of the N1 strain. These two purified compounds were identified as iturin A and surfactin by HPLC and LCMS. The purified lipopeptides were evaluated for plant disease control activity against seven plant diseases. Crude extracts and purified compounds applied at 500 ${\mu}g/ml$ concentration controlled tomato gray mold, tomato late blight and pepper anthracnose effectively with over 70% disease control value. While iturin showed broad spectrum activity against all tested plant diseases, the control activity by surfactin was limited to tomato gray mold, tomato late blight, and pepper anthracnose. Although antifungal compounds from B. licheniformis N1 exhibited disease control activity, our results suggested that bacterial cells present in the N1E formulation also contribute to the disease control activity together with the antifungal compounds.

• The Plant Pathology Journal
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• v.39 no.6
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• pp.614-624
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• 2023

Botrytis cinerea is a major fungal plant pathogen that causes gray mold disease in strawberries, leading to a decrease in strawberry yield. While benzimidazole is widely used as a fungicide for controlling this disease, the increasing prevalence of resistant populations to this fungicide undermines its effectiveness. To investigate benzimidazole resistant B. cinerea in South Korea, 78 strains were isolated from strawberries grown in 78 different farms in 2022, and their EC₅₀ values for benzimidazole were examined. As a result, 64 strains exhibited resistance to benzimidazole, and experimental tests using detached strawberry leaves and the plants in a greenhouse confirmed the reduced efficacy of benzimidazole to control these strains. The benzimidazole resistant strains identified in this study possessed two types of mutations, E198A or E198V, in the TUB2 gene. To detect these mutations, TaqMan probes were designed, enabling rapid identification of benzimidazole resistant B. cinerea in strawberry and tomato farms. This study utilizes TaqMan real-time polymerase chain reaction analysis to swiftly identify benzimidazole resistant B. cinerea, thereby offering the possibility of effective disease management by identifying optimum locations and time of application.

• Journal of Bio-Environment Control
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• v.21 no.4
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• pp.404-410
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• 2012

This study was conducted to examine effects of harvest time (09:00 vs. 14:00), precooling at $4^{\circ}C$ vs. no precooling, and storage temperature (4 vs. $8^{\circ}C$) on the storage life of 'Maehyang' strawberry fruits for export. Fruits at a 60% ripe stage were harvested from a commercial greenhouse in Gyeongsangnamdo, Jinju on May 4, 2010. Fruits were precooled by a forced draft cooling for three hours, transported for about 30 minutes and then stored, immediately. Small precoolers set in the farm were used for precooling. Fruits were placed in constant temperature chamber (4 or $8^{\circ}C$) after packaging using PVC wrap and a cardboard box. Fruits were examined for their changes in weight, hardness, Hunter color values, soluble solids content (SSC), and incidence of gray mold (Botrytis cinerea) during storage at a two days interval from May 6 to May 14, 2010. Hardness and SSC decreased as the ripening stage progressed. The Hunter's 'L' and 'a' value of fruit color decreased as time passed. Also, fresh weight decreased during storage at all temperatures. Soft rot appeared on epidermal tissues and followed by gray mold. Incidence of gray mold was greater at $8^{\circ}C$ storage temperature than in $4^{\circ}C$ storage temperature. However, no difference by the harvested time and precooling. The results indicate that effectiveness for keeping the freshness was best achieved by precooling at $4^{\circ}C$ and storage at $4^{\circ}C$, respectively.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.384.4-385
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• 2001