• The Plant Pathology Journal
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• v.29 no.2
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• pp.168-173
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• 2013

Apple ring rot disease, caused by Botryosphaeria dothidea (Moug. ex. Fr) Ces. et de Not., is one of the most important diseases on apple fruits. In this study, strain 9001 isolated from healthy apple fruits from an infested orchard was evaluated for its biocontrol activity against apple ring rot in vitro and in vivo. Strain 9001 showed obvious antagonistic activity to B. dothidea YL-1 when plated on potato dextrose agar. Soaking healthy apples in the bacterial suspensions of strain 9001 prior to artificial inoculation of fungal pathogen resulted in a dramatic decrease in disease incidence when compared to the control. Moreover, either field application in the growth season or postharvest treatment of apples from infected orchards with bacterial suspensions of strain 9001 resulted in significantly reduced disease incidence within the storage period for 4 months at room temperature. Based on the phylogenetic analysis of 16S rRNA and the gyrA gene, strain 9001 was identified as Bacillus amyloliquefaciens. These results indicated that B. amyloliquefaciens 9001 could be a promising agent in biocontrol of apple ring rot on fruit, which might help to minimize the yield loss of apple fruit during the long postharvest period.

• The Korean Journal of Pesticide Science
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• v.2 no.2
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• pp.83-89
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• 1998

The occurrence of postharvest disease of apple was surveyed from 1995 to 1997 in the major apple-producing area in Korea. Ten genera including Alternaria spp., Botryosphaeria dothidea, Botrytis cinerea, Fusarium spp., and Penicillium spp. were isolated from the decayed apple fruits. Of these, B. cinerea, Penicillium spp. and Fusarium spp. were frequently isolated and were highly pathogenic to apple fruits. Optimum temperature of mycelial growth for Penicillium spp. ranged from 10 to $30^{\circ}C$ and that of mycelial growth for B. cinerea and Alternaria spp. ranged from 5 to $30^{\circ}C$. Optimum temperature of sporulation of Penicillium spp. and Alternaria spp. ranged $15{\sim}25^{\circ}C$ and $10{\sim}20^{\circ}C$, respectively. Occurrence of postharvest disease of apple increased in neglecting selection of wounded fruits before storing apples. Most of these fungi causing postharvest diseases such as Penicillium spp, Botrytis cinerea and Alternaria spp. were isolated from healthy fruits sampled at apple orchard. These results suggested that posthavest diseases of apple were originated from apple fruits contaminated from apple orchard and occurred during storage. In addition, five fungicides including prochloraz EC, fenari EC, captan WP, benomyl WP and folpet WP suppressed posthavest diseases when they sprayed on apple fruits at 30 days before harvesting.

• The Plant Pathology Journal
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• v.36 no.6
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• pp.570-578
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• 2020

Rhizopus rot is a serious postharvest disease of various crops caused by Rhizopus spp. and controlled mainly by synthetic fungicides. We detected the antifungal activity of a culture extract of Setosphaeria rostrata F3736 against Rhizopus oryzae. The active ingredient was identified as moriniafungin, a known sordarin derivative, which showed minimum inhibitory concentrations of 1-8 ㎍/ml against Colletotrichum spp. and 0.03-0.13 ㎍/ml against Rhizopus spp. in vitro. Moriniafungin showed protective control efficacies against Rhizopus rot on apple and peach fruits. Treatment with 25 ㎍/ml moriniafungin delimited the lesion diameter significantly by 100% on R. oryzae-inoculated apple fruits compared with the non-treated control. Treatment with 0.04 ㎍/ml of moriniafungin reduced the lesion diameter significantly by 56.45%, and treatment with higher concentrations of 0.2-25 ㎍/ml reduced the lesion diameter by 70-90% on Rhizopus stolonifer var. stolonifer-inoculated peach fruit. These results suggest moriniafungin has potential as a control agent of postharvest diseases caused by Rhizopus spp.

• Journal of Microbiology and Biotechnology
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• v.27 no.3
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• pp.624-632
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• 2017

Penicillium expansum causes blue mold rot, a prevalent postharvest disease of pome fruit, and is also the main producer of the patulin. However, knowledge on the molecular mechanisms involved in this pathogen-host interaction remains largely unknown. In this work, a two-dimensional gel electrophoresis-based proteomic approach was applied to probe changes in P. expansum 3.3703 cultivated in apple juice medium, which was used to mimic the in planta condition. The results showed that the pH value and reducing sugar content in the apple juice medium decreased whereas the patulin content increased with the growing of P. expansum. A total of 28 protein spots that were up-regulated in P. expansum when grown in apple juice medium were identified. Functional categorization revealed that the identified proteins were mainly related to carbohydrate metabolism, secondary metabolism, protein biosynthesis or degradation, and redox homeostasis. Remarkably, several induced proteins, including glucose dehydrogenase, galactose oxidase, and FAD-binding monooxygenase, which might be responsible for the observed medium acidification and patulin production, were also detected. Overall, the experimental results provide a comprehensive interpretation of the physiological and proteomic responses of P. expansum to the host plant environment, and future functional characterization of the identified proteins will deepen our understanding of fungi-host interactions.

• Research in Plant Disease
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• v.29 no.4
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• pp.390-398
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• 2023

Apple white rot, caused by Botryosphaeria dothidea, is one of the important diseases in Korea. B. dothidea can cause pre- and postharvest decay on apple fruit as well as canker and dieback of apple trees. In this study, we isolated bacteria from the trunk of apple trees and tested their antagonistic activity against B. dothidea. Five bacterial isolates (23-168, 23-169, 23-170, 23-172, and 23-173) were selected that were most effective at inhibiting the mycelial growth of the pathogens. The isolate 23-172 was identified as Bacillus amyloliquefaciens and four isolates 23-168, 23-169, 23-170, and 23-173 were identified as Bacillus velezensis by RNA polymerase beta subunit (rpoB) and DNA gyraseA subunit (gyrA) gene sequencing. All isolates showed strong antagonistic activity against B. dothidiea as well as Colletotrichum fructicola and Diaporthe eres. All isolates exhibited cellulolytic, proteolytic and phosphate solubilizing activities. In particular, two isolates 23-168, 23-169 were shown to significantly reduce the size of white rot lesions in pretreated apple fruits. These results will provide the basis for the development of a fungicide alternative for the control of white rot of apple.