• The Plant Pathology Journal
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• v.27 no.4
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• pp.360-366
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• 2011

Bacterial leaf spot of Euphorbia pulcherrima has been reported in many countries. Characterization by polyphasic approaches indicated that the isolates from India, USA and New Zealand could be distinguished based on rep-PCR profiles and gyrB phylogenies, while the Chinese isolates should be ascribed to Xanthomonas axonopodis pv. poinsettiicola.

• The Plant Pathology Journal
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• v.25 no.4
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• pp.429-432
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• 2009

An unreported disease of apricot was observed in orchards in Zhejiang province, China. Symptoms started as water soaked lesions on the fruit surface. Later, water-soaked areas developed and spread to the entire fruit, resulting in soft rot of the whole fruit. The causal organism isolated from symptomatic fruits was identified as Burkholderia cepacia based on its biochemical and physiological characteristics and confirmed by the cellular fatty acid composition and Biolog data as well as 16S rRNA gene sequence analysis. The bacterial isolates caused similar symptoms when inoculated onto fruits of apricot. In addition, European plum, Japanese plum, nectarine and kiwifruit were susceptible to the B. cepacia pathogen. However, the B. cepacia pathogen failed to cause any visible symptoms when it was inoculated onto 16 other fruits. This is the first report of a bacterial disease of apricot caused by B. cepacia in China.

• Mycobiology
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• v.51 no.4
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• pp.264-272
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• 2023

Onion (Allium cepa L.) is an economically important vegetable crop worldwide. However, various fungal diseases, including Fusarium basal rot (FBR), neck rot, and white rot, reduce onion production or bulb storage life. FBR caused by Fusarium species is among the most destructive onion diseases. In this study, we identified Fusarium species associated with FBR in Jeolla and Gyeongsang Provinces in South Korea and evaluated fungicides against the pathogens. Our morphological and molecular analyses showed that FBR in onions is associated with Fusarium commune, Fusarium oxysporum, and Fusarium proliferatum. We selected seven fungicides (fludioxonil, hexaconazole, mandestrobin, penthiopyrad, prochloraz-manganese, pydiflumetofen, and tebuconazole) and evaluated their inhibitory effects on mycelial growth of the pathogens at three different concentrations (0.01, 0.1, and 1 mg/mL). We found that prochloraz-manganese was highly effective, inhibiting 100% of the mycelial growth of the pathogens at all concentrations, followed by tebuconazole. Fludioxonil showed < 50% inhibition at 1 mg/mL for the tested isolates.

• The Plant Pathology Journal
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• v.32 no.6
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• pp.575-579
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• 2016

Burkholderia glumae (bacterial grain rot), Xanthomonas oryzae pv. oryzae (bacterial leaf blight), and Acidovorax avenae subsp. avenae (bacterial brown stripe) are major seedborne pathogens of rice. Based on the 16S and 23S rDNA sequences for A. avenae subsp. avenae and B. glumae, and transposase A gene sequence for X. oryzae pv. oryzae, three sets of primers had been designed to produce 402 bp for B. glumae, 490 bp for X. oryzae, and 290 bp for A. avenae subsp. avenae with the $63^{\circ}C$ as an optimum annealing temperature. Samples collected from naturally infected fields were detected with two bacteria, B. glumae and A. avenae subsp. avenae but X. oryzae pv. oryzae was not detected. This assay can be used to identify pathogens directly from infected seeds, and will be an effective tool for the identification of the three pathogens in rice plants.

• BMB Reports
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• v.43 no.8
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• pp.573-578
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• 2010

Several organophosphorus (OP) insecticides can selectively kill the silkworm maggot, Exorista sorbillans (Es) (Diptera: Tachinidae), while not obviously affecting the host (Bombyx mori) larvae, but the mechanism is not yet clear. In this study, the cDNA encoding an acetylcholinesterase (AChE) from the field Es was isolated. One point mutation (Gly353Ala) was identified. The Es-353G AChE and Es-353A AChE were expressed in baculovirus-insect cell system, respectively. The inhibition results showed that for eserine and Chlorpyrifos, Es-353A AChE was significantly less sensitive than Es-353G AChE. Meanwhile, comparison of the I50 values of eserine, dichlorvos, Chlorpyrifos and omethoate of recombinant Es AChEs with its host (Bombyx mori) AChEs indicated that, both Es AChEs are more sensitive than B. mori AChEs. The results give an insight of the mechanism that some OP insecticides can selectively kills Es while without distinct effect on its host, B. mori.

• The Plant Pathology Journal
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• v.34 no.4
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• pp.327-334
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• 2018

Northern corn leaf spot and southern corn leaf blight caused by Cochliobolus carbonum (anamorph, Bipolaris zeicola) and Cochliobolus heterostrophus (anamorph, Bipolaris maydis), respectively, are common maize diseases in Korea. Accurate detection of plant pathogens is necessary for effective disease management. Based on the polyketide synthase gene (PKS) of Cochliobolus carbonum and the nonribosomal peptide synthetase gene (NRPS) of Cochliobolus heterostrophus, primer pairs were designed for PCR to simultaneously detect the two fungal pathogens and were specific and sensitive enough to be used for duplex PCR analysis. This duplex PCR-based method was found to be effective for diagnosing simultaneous infections from the two Cochliobolus species that display similar morphological and mycological characteristics. With this method, it is possible to prevent infections in maize by detecting infected seeds or maize and discarding them. Besides saving time and effort, early diagnosis can help to prevent infections, establish comprehensive management systems, and secure healthy seeds.

• Research in Plant Disease
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• v.19 no.3
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• pp.177-182
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• 2013

Resvestrol has been known to inhibit bacterial and fungal growth in vitro, and can be accumulated in plant to concentrations necessary to inhibit microbial pathogens. Hence, stilbene synthase gene has been used to transform to synthesize resveratrol in heterologous plant species to enhance resistance against pathogens. In the present study, we investigated the antimicrobial activities of resveratrol and piceid to bacterial and fungal pathogens, which causing severe damages to rice plants. In addition, disease resistance was compared between transgenic rice varieties, Iksan 515 and Iksan 526 transformed with stlibene synthase gene and non-transgenic rice varieties, Dongjin and Nampyeong. Minimum inhibitory concentration of resveratrol for Burkolderia glumae was 437.5 ${\mu}M$, and the mycelial growth of Biplaris oryzae was slightly inhibited at concentration of 10 ${\mu}M$. However, other bacterial and fungal pathogens are not inhibited by resveratrol and piceid. The expression of the stilbene synthase gene in Iksan 515 and Iksan 526 did not significantly enhanced resistance against bacterial grain rot, bacterial leaf blight, sheath blight, and leaf blight. This study is the first report on the effect of resveratrol and piceid against pathogens of rice plant, and changes of disease resistance of transgenic rice plants transformed with stilbene synthase gene.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.91-94
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• 2009

An unreported disease of garlic was observed in commercial fields in Jiangsu province, China. The symptoms started as water soaked lesions at the base of the leaves. Later, water-soaked areas developed on stems and spread to the internal tissues, followed by yellowing and necrosis along leaf edges and soft rot of the stems. The causal organism isolated from symptomatic plants was identified as Pseudomonas fluorescens based on its biochemical and physiological characteristics and confirmed by the cellular fatty acid composition and Biolog data as well as 168 rRNA gene sequence analysis. The bacterial isolates caused similar symptoms when inoculated onto garlic plants. In addition, leek and shallot were susceptible to the P. fluorescens pathogen. However, the P. fluorescens pathogen failed to cause any symptoms when it was inoculated onto 15 other plants. This is the first report of a bacterial disease of garlic caused by P. fluorescens in China.

• The Plant Pathology Journal
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• v.26 no.2
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• pp.189-193
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• 2010

The in vitro antibacterial properties of two kinds of chitosan solutions and their effect in protection of broccoli from bacterial head rot disease were evaluated. Results showed that the two kinds of chitosan solution at different concentrations exhibited strong antibacterial activity against Pseudomonas fluorescens. However, the antibacterial activity of chitosan A solution increased with the increase of chitosan concentration up to 0.10 mg/ml while the antibacterial activity of chitosan B solution increased with the increase of chitosan concentration up to 0.05 mg/ml. In addition, the antibacterial activity of chitosan A and chitosan B solution of 0.10 mg/ml increased with the incubation time within 12 h and 24 h, respectively. The disease incidence and the lesion diameter of broccoli inoculated with P. fluorescens were significantly reduced when plants were either pretreated or post-treated with six different combinations of chitosan solutions. Overall, the results indicated that the two kinds of chitosan solutions had a potential in controlling bacterial head rot of broccoli.

• The Plant Pathology Journal
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• v.26 no.3
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• pp.223-230
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• 2010

The Burkholderia cepacia complex isolates causing bacterial fruit rot of apricot were characterized by speciesspecific PCR tests, recA-HaeIII restriction fragment length polymorphism (RFLP) assays, rep-PCR genomic fingerprinting, recA gene sequencing, and multilocus sequence typing (MLST) analysis. Results indicated that the isolates Bca 0901 and Bca 0902 gave positive amplifications with primers specific for B. vietnamiensis while the two bacterial isolates showed different recA-RFLP and rep-PCR profiles from those of B. vietnamiensis strains. In addition, the two bacterial isolates had a higher proteolytic activity compared with that of the non-pathogenic B. vietnamiensis strains while no cblA and esmR marker genes were detected for the two bacterial isolates and B. vietnamiensis strains. The two bacterial isolates were identified as Burkholderia seminalis based on recA gene sequence analysis and MLST analysis. Overall, this is the first characterization of B. seminalis that cause bacterial fruit rot of apricot.