• Research in Plant Disease
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• v.26 no.3
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• pp.159-169
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• 2020

Pectobacterium carotovorum subsp. carotovorum (Pcc) causes bacterial soft rot on a wide range of crops worldwide, especially in countries with warm and humid climates. This study was conducted to establish an efficient screening method for resistant cultivars of Chinese cabbage to bacterial soft rot. Resistance degrees of 65 commercial Chinese cabbage cultivars to the Pcc KACC 10225 isolate were investigated. For further study, three Chinse cabbage cultivars (Taebong, Hadaejangkun, CR Alchan) showing different level of resistance to the bacterium were selected. The development of bacterial soft rot on the cultivars was tested according to several conditions such as growth stage of Chinse cabbage seedling, inoculum concentration, and incubation temperature after inoculation. On the basis of the results, we suggest that an efficient screening method for resistant Chinses cabbage to Pcc is to inoculate twenty one-day-old seedlings with a bacterial suspension of Pcc at a concentration of 1×10⁷ cfu/ml, and to incubate the plants in a dew chamber at 25℃ for 24 hr and then to cultivate in a growth room at 25℃ and 80% relative humidity with 12-hr light per day.

• The Korean Journal of Pesticide Science
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• v.13 no.4
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• pp.325-331
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• 2009

Three beneficial bacterial agents, Lactobacillus strain KLF01, Lactococcus strain KLC02 and Paenibacillus strain KPB3 were showed clear zone against plated Pectobacterium carotovorum subsp. carotovorum (Pcc) soft rot pathogen. In greenhouse test, bio-control efficacy was more significantly effective in the treatments by KLC02 and KPB3 as 64%, 50%, 56% and 66%, 57%, 58% according to date of evaluation, respectively. In case of KLF01 control effect was relatively lower than treatments of KLC02 and KPB3 but its efficacy was still significantly observed when compared to control (only water treatment). Furthermore, KLF01, KLC02 and KPB3 showed 55%, 60% and 62% bio-control efficacy, respectively in field test from early March to late July of 2009. Thus, we suggest that these strains can be useful as bio-control agents against soft rot caused by Pcc.

• The Plant Pathology Journal
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• v.35 no.2
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• pp.178-187
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• 2019

Plants are exposed to biotic stresses caused by pathogen attack and complex abiotic stresses including heat and drought by dynamic climate changes. To alleviate these stresses, we investigated two bacterial stains, H26-2 and H30-3 in two cultivars ('Ryeokkwang' and 'Buram-3-ho') of Chinese cabbage in plastic pots in a greenhouse. We evaluated effects of bacterial strains on plant growth-promotion and mitigation of heat and drought stresses; the role of exopolysaccharides as one of bacterial determinants on alleviating stresses; biocontrol activity against soft rot caused by Pectobacterium carotovorum subsp. carotovorum PCC21. Strains H26-2 and H30-3 significantly increased fresh weights compared to a $MgSO_4$ solution; reduced leaf wilting and promoted recovery after re-watering under heat and drought stresses. Chinese cabbages treated with H26-2 and H30-3 increased leaf abscisic acid (ABA) content and reduced stomatal opening after stresses treatments, in addition, these strains stably colonized and maintained their populations in rhizosphere during heat and drought stresses. As well as tested bacterial cells, exopolysaccharides (EPS) of H30-3 could be one of bacterial determinants for alleviation of tested stresses in Chinese cabbages, however, the effects were different to cultivars of Chinese cabbages. In addition to bacterial activity to abiotic stresses, H30-3 could suppress incidence (%) of soft rot in 'Buram-3-ho'. The tested strains were identified as Bacillus aryabhattai H26-2 and B. siamensis H30-3 based on 16S rRNA gene sequence analysis. Taken together, H26-2 and H30-3 could be candidates for both plant growth promotion and mitigation of heat and drought stresses in Chinese cabbage.

• Research in Plant Disease
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• v.29 no.1
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• pp.64-71
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• 2023

In October 2021, soft rot disease seriously affected radish crop in Dangjin, Chungcheongnam-do, Korea. The infected radishes were stunted and turned dark green, with yellowish leaf foliage. A slimy, wet, and decayed pith region was observed in the infected roots. The bacterial strain KNUB-03-21 was isolated from infected roots. The biochemical and morphological characteristics of the isolate were similar to those of Pectobacterium brasiliense. Phylogenetic analysis based on the sequences of the 16S rRNA region and the concatenated DNA polymerase III subunit tau (dnaX), leucine-tRNA ligase (leuS), and recombinase subunit A (recA) genes confirmed that the isolate is a novel strain of P. brasiliense. Artificial inoculation of radish with P. brasiliense KNUB-03-21 resulted in soft rot symptoms similar to those observed in infected radish in the field; subsequently, P. brasiliense KNUB-03-21 was reisolated and reidentified. To our knowledge, this is the first report of P. brasiliense as a causal pathogen of radish soft rot in Korea.

• Research in Plant Disease
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• v.29 no.4
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• pp.445-451
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• 2023

Zamioculcas zamiifolia is a popular indoor ornamental plant in Korea. In August 2021, a severe outbreak of soft rot disease affected Z. zamiifolia in Emseong, Chungcheongbuk-do, Korea. Infected plants displayed wilting, water-soaked lesions, stem collapse, and green-brown discoloration. The bacterial strain KNUB-05-21 was isolated from infected stems and identified as Pectobacterium aroidearum using 16S rRNA nucleotide sequencing and multilocus sequence analysis based on partial sequences of dnaX, leuS, and recA genes. Confirmation of its affiliation with P. aroidearum was also obtained through biochemical and morphological characterization. To confirm the pathogenicity of strain KNUB-05-21, its suspension was injected into Z. zamiifolia stems. Within a week, soft rot developed on the stems, exhibiting symptoms similar to those observed in field-infected plants. The reisolated strain was identical to those of P. aroidearum. Before this study, P. aroidearum was not reported as a causative pathogen of Z. zamiifolia soft rot in Korea.

• Research in Plant Disease
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• v.29 no.4
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• pp.452-458
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• 2023

In the Goesan region, located in Chungcheongbuk-do, Korea, a significant outbreak of soft rot infections was documented in August 2021, affecting fruits of Momordica charantia, commonly known as bitter melon or bitter gourd. The symptoms included a noticeable transition to yellowing in the affected fruits, eventually leading to their collapse. The bacterial strain KNUB-09-21 was isolated from the diseased fruits. Molecular analysis, using the sequences of the 16S rRNA region and three housekeeping genes (dnaX, recA, and leuS), along with the results of compound utilization in the API ID 32 GN system, provide strong evidence for the identification of the isolate KNUB-09-21 as Pectobacterium brasiliense. The pathogenicity of strain KNUB-09-21 on M. charantia was confirmed through a controlled inoculation test. Within two days, inoculated fruits displayed soft rot symptoms closely resembling those observed in naturally affected fruits. This is the first report of soft rot on M. charantia in Korea.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.362.1-362
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• 2001

• Journal of Bio-Environment Control
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• v.6 no.4
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• pp.317-323
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• 1997

Incidence of soybean sprout rot by Erwinia carotovora subsp. carotovora was examined under several artificial conditions. Under higher temperatures over 3$0^{\circ}C$, disease incidence was increased and the rate of soft rot incidence was 22% at 35$^{\circ}C$. Artificial injuries of inner cotyledon and seed coat induced the disease above 70% and inhibited the soybean sprout growth. Relative humidity above 90% increased the soft rot to 33% and inhibited soybean sprout growth. When the leaked water collected from soybean sprout was reused for irrigation, the disease incidence was increased.

• Research in Plant Disease
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• v.30 no.1
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• pp.95-98
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• 2024

In a survey conducted in March 2023, Euphorbia hypogaea plants cultivated within greenhouses in Yongin, Korea exhibited water-soaked areas near the stem base, close to the soil. Subsequent isolation from diseased E. hypogaea led to the identification of a bacterial strain, designated as CBNUMPBL-103. The isolate was identified as Dickeya dadantii through sequencing of the 16s rRNA and phylogenetic analysis. The pathogenicity of the isolate was confirmed by inoculating it into healthy E. hypogaea, resulting in the manifestation of similar symptoms observed during the survey. The re-isolated strain recovered from inoculated plants showed a similar morphology with the inoculated strain. This is the first documentation of D. dadantii causing soft rot of E. hypogaea in Korea.

• Research in Plant Disease
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• v.6 no.1
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• pp.6-9
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• 2000

Nine samples of soft rotten roots and blighted leaves of Ficus spp. plants were collected from the vinyl-houses in Taejeon, Seongnam, Suweon and Yangjae in 1988 and pathogenic bactea were isolated from them Results of the studies on morphological, cultural, physiologucal and pathological characteristics indicated that the bacteria from Ficus retusa were Pseudomonas cichorii, from Ficus retusa \`Golden leaf\` and Ficus benjamina were P.viridiflava. These are the first description of bacteria which caused the diseases on Ficus spp. in Korea. We proposed to name the disease of Ficus retusa by P. cichorii as \"bacterial root rot of Ficus retusa\" and Ficus retusa(Golden leaf) and Ficus benjamina by P. viridiflava as \"bacterial leaf blight of Ficus retusa (Golden leaf)\", \"bacterial blight of Ficus benjamina\", respectively.