• The Plant Pathology Journal
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• v.35 no.6
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• pp.635-643
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• 2019

To detect Xanthomonas arboricola pv. pruni, a loopmediated isothermal amplification (LAMP) detection method were developed. The LAMP assay was designed to test crude plant tissue without pre-extraction, or heating incubation, and without advanced analysis equipment. The LAMP primers were designed by targeting an ABC transporter ATP-binding protein, this primer set was tested using the genomic DNA of Xanthomonas and non-Xanthomonas strains, and a ladder product was generated from the genomic DNA of X. arboricola pv. pruni strain but not from 12 other Xanthomonas species strains and 6 strains of other genera. The LAMP conditions were checked with the healthy leaves of 31 peach varieties, and no reaction was detected using either the peach leaves or the peach DNA as a template. Furthermore, the high diagnostic accuracy of the LAMP method was confirmed with 13 X. arboricola pv. pruni strains isolated from various regions in Korea, with all samples exhibiting a positive reaction in LAMP assays. In particular, the LAMP method successfully detected the pathogen in diseased peach leaves and fruit in the field, and the LAMP conditions were proven to be a reliable diagnostic method for the specific detection and identification of X. arboricola pv. pruni in peach orchards.

• Research in Plant Disease
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• v.16 no.2
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• pp.125-128
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• 2010

Bacterial black spot disease of prune fruit (Prunus salicina cv. formosa) has outbroke around major prune production area, Gimcheon, Euiseong and Gunwi in Gyungbuk province and has caused severe economic loss. Integrons PCR primer was designed along with sample pre-incubation and nested PCR method to enhance detection sensitivity for early detection of bacteria in fields. Designed integrons PCR primer successfully detected Xanthomonas arboricola pv. pruni from field collected samples, fruit, leaf, branch and even in raindrop collected from prune orchard. Pre-incubation along with nested PCR enhanced sensitivity to detect X. arboricola pv. pruni from seemingly healthy looking, symptomless branches. Designed integrons PCR can be used in prune nursery fields and in plant quarantine practice for the detection of X. arboricola pv. pruni.

• Journal of Life Science
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• v.19 no.5
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• pp.684-687
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• 2009

Xanthomonas arboricola pv. pruni, the causal agent of bacterial shot holes in stone fruits, was known to have a low population diversity. To investigate the genetic characteristics of X. arboricola pv. pruni isolated in Korea, three strains which have identical 16S rDNA sequences - including type strain (LMG852), Japanese isolate (MAFF301420) and Korean isolate (XWD1) - were analysed based on the nucleotide sequences of three DNA regions and RAPD pattern. No sequence diversity among the three strains was found within the ITS, glnA and atpD gene sequences. However, five of 756 nucleotides of the atpD gene determined (accession number FJ429319) were different from those of the French strain available from the Genbank database. RAPD analyses performed with 40 different arbitrary primers revealed that two strains isolated from Korea and Japan showed similarity in their band patterns distinguished by type strain. These results suggest that Korean and Japanese strains are very close and belong to a population with a low genetic diversity, and might have a different origin from strains found in West Europe.

• Korean Journal of Environmental Agriculture
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• v.40 no.1
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• pp.20-32
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• 2021

BACKGROUND: Bacterial shot hole of stone fruits is a seriuos plant disease caused by Xanthomonas arboricola pv. pruni (Xap). Techniques to control the disease are required. In this study, microorganisms with antibacterial activity were isolated to develop as a microbial agent against the bacterial shot hole. METHODS AND RESULTS: An isolate with the strongest activity among the isolates was identified as Streptomyces avidinii based on 16S rRNA gene sequence analysis and designated Streptomyces sp. J46. J46 showed suppression of bacterial leaf spot with a control value of 90% at 10 times-diluted cell free supernatant. To investigate antibacterial metabolites produced by J46, the supernatant of J46 was extracted with organic solvents, and the extracts were subjected to chromatography works. Antibacterial metabolites were not extractable with organic solvents. Both reverse and normal phase techniques were not successful because the metabolites were extremely water soluble. The antibacterial metabolites were not volatiles but protein compounds based on hydrolysis enzyme treatment. CONCLUSION: Our study suggests that Streptomyces sp. J46 may be a potential as an microbial agent against bacterial shot hole. Further study to identify the metabolites is required in more detail.

• Research in Plant Disease
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• v.18 no.1
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• pp.40-44
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• 2012

Xanthomonas arboricola pv. pruni is the causal agent of bacterial black spot disease on some stone fruits, e.g. peach, plum and apricot. To evaluate pathogenicity of Xanthomonas arboricola pv. pruni strain from plum, inoculum of the isolated strain was spray inoculated to fruits and leaves of apricot, Japanese apricot and plum. Apricot and Japanese apricot showed severe black spot symptoms on fruits and shot hole symptoms on leaves. In case of apricot, about fifty percent of fruits did not grow and dropped by hypersensitive reaction to spray infection. Plum, cv. Formosa was very susceptible, showing severe black injury lesions on fruits and cankers on leaves and new twigs. On the other hand, plum cv. Daesukjosaeng, was highly resistant. Fruits of several plum cultivars such as Formosa and Chuhee were severely infected at natural infected orchards by X. arboricola pv. pruni. Where as those of Daesukjosaeng, Taeyang, Soldam and Hongrogen were moderately infected.

• Research in Plant Disease
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• v.18 no.4
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• pp.349-353
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• 2012

Xanthomonas arboricola pv. pruni causes black spot symptom on fruit of plum, resulting in yield loss by reduction of marketable fruit production. To develop an effective control program, some chemicals were sprayed in various scheme during dormant season and growing season after blooming period. Copper-based chemicals were sprayed during dormant season and antibiotic-based chemicals were sprayed during fruit growing season. Sprays of antibiotic-based chemicals in growing season was more effective than copper-based chemicals sprays in dormant season. Three applications of antibiotic-based chemicals in 10 days interval starting 10 days after full blooming controlled disease incidence as much as 93%, whereas applications of copper-based chemicals in dormant season controlled 26-42%. Antibiotic-based chemicals application starting 10 days after full blooming was more effective than starting 20 or 30 days after full blooming.

• Research in Plant Disease
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• v.29 no.2
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• pp.168-173
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• 2023

Agricultural antibiotics are widely used to inhibit the growth of phytopathogenic bacteria involved in plant diseases. However, continuous antibiotic overuse in crop production may lead to the development of antibiotic resistance in phytopathogenic bacteria. This study was conducted to evaluate the resistance to three different agricultural antibiotics (oxytetracycline+streptomycin, streptomycin, and validamycin A) in 91 strains of phytopathogenic bacteria including Pectobacterium carotovorum, Pseudomonas syringae pv. actinidiae, Clavibacter michiganensis subsp. michiganensis, C. michiganensis subsp. capsici, and Xanthomonas arboricola pv. pruni. Bacterial growth in the presence of various concentrations of validamycin A was also assessed spectrophotometrically by analyzing the optical density. All strains did not grow when the cells were exposed to oxytetracycline+streptomycin or 100× of streptomycin. However, among the 91 strains, 4% and 2% strains showed bacterial growth at the concentrations of 1× and 10× of streptomycin, respectively. Furthermore, 97%, 93%, and 73% strains were resistant to the 1×, 10×, and 100× of validamycin A, respectively, and especially, P. carotovorum contained the highest resistance to the validamycin A. Minimum bactericidal concentration values of validamycin A did not correlate with the patterns of agricultural antibiotic resistance. Further studies are needed to understand the incidence and development of antibiotic resistance in phytopathogenic bacteria.

• Journal of Microbiology and Biotechnology
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• v.27 no.10
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• pp.1763-1772
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• 2017

This study aimed to isolate and characterize antibacterial metabolites from Pharbitis nil seeds and investigate their antibacterial activity against various plant pathogenic bacteria. The methanol extract of P. nil seeds showed the strongest activity against Xanthomonas arboricola pv. pruni (Xap) with a minimum inhibition concentration (MIC) value of $250{\mu}g/ml$. Among the three solvent layers obtained from the methanol extract of P. nil seeds, only the butanol layer displayed the activity with an MIC value of $125{\mu}g/ml$ against Xap. An antibacterial fraction was obtained from P. nil seeds by repeated column chromatography and identified as pharbitin, a crude resin glycoside, by instrumental analysis. The antibacterial activity of pharbitin was tested in vitro against 14 phytopathogenic bacteria, and it was found to inhibit Ralstonia solanacearum and four Xanthomonas species. The minimum inhibitory concentration values against the five bacteria were $125-500{\mu}g/ml$ for the n-butanol layer and $31.25-125{\mu}g/ml$ for pharbitin. In a detached peach leaf assay, it effectively suppressed the development of bacterial leaf spot, with a control value of 87.5% at $500{\mu}g/ml$. In addition, pharbitin strongly reduced the development of bacterial wilt on tomato seedlings by 97.4% at $250{\mu}g/ml$, 7 days after inoculation. These findings suggest that the crude extract of P. nil seeds can be used as an alternative biopesticide for the control of plant diseases caused by R. solanacearum and Xanthomonas spp. This is the first report on the antibacterial activity of pharbitin against phytopathogenic bacteria.

• The Korean Journal of Pesticide Science
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• v.19 no.2
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• pp.106-112
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• 2015

This experiment was carried out to investigate the best spray timing for the control of the bacterial shot hole with Bordeaux mixture (6-6) after wintering in the peach orchard. We sprayed Bordeaux mixture (6-6) on 'Mibaekdo', 'Yumyeong' and 'Cheonhong' of peach verities from late-March to mid-April in 2001, 2002 and 2014, and examined how much bacterial shot hole and chemical injure occurred. The infection rate of bacterial shot hole according to spray time was 10.2 to 11.7% at leaves, and 1.7 to 2.2% at fruits in 2002. And Efficacy of the Bordeaux mixture treatment for control of bacterial shot hole at full blooming time 21.2 to 30.4% at leaves, 1.7 to 4.4% at fruits in 2014. The chemical injure occurred slightly for one week hence. The fruit bearing rate was 20.7 to 29.8% at 'Mibaekdo', and 35.4 to 61.9% at 'Yumyeong' peach trees. When the spray at the time of blooming period by bordeaux mixture was investigated the control effect of bacterial shot hole disease. The infected leaves was better than 21 to 25% twice the quantity of finished products and bordeaux self-preparation about 28 to 30% base quantity of finished products, also the control efficacy was higher in infected fruits trends in bordeaux self-preparation method and twice the quantity of finished products.

• Horticultural Science & Technology
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• v.32 no.6
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• pp.912-916
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• 2014

Japanese apricot (Prunus mume Siebold and Zucc.) is a deciduous tree of the family Rosaceae, and it has long been used as a folk remedy for cough and dyspepsia. A new cultivar 'Okjoo' was developed from a cross between 'Gyokuei' and 'Rinsyu' carried out at the National Institute of Horticultural & Herbal Science in 1993. It w as s elected for good shape, large size and high yield capacity in 2006, and then it was granted official patent No. 4556 in 2013. It blooms 4 days and 2 days earlier than 'Gyokuei' and 'Rinsyu', respectively. Its flower petal color is pink, and the pollen amount is negligible. Its S-genotype, determined using Polymerase Chain Reaction with a S-RNase gene-specific primer pair, is $S_3S_6$. The average optimum harvest time of 'Okjoo' is late June. The fruit is round in shape and its suture is shallow. Average fruit weight is 18.5 g, and it contains total soluble solids $7.66^{\circ}Brix$ and titratable acidity at 4.81%. Fruit skin color is green. Sometimes only the light side of the fruits seems to develop blush. The incidence levels of scab (Cladosporium carpophilum Thumen) and bacterial shot hole (Xanthomonas arboricola pv. Pruni) are quite low. Consequently, 'Okjoo' seems to be a promising new cultivar for Japanese apricot growers.