• 식물병연구
• /
• 제24권4호
• /
• pp.339-341
• /
• 2018

Amaranth has the potential for good materials related to nutrients and health benefits. There are several diseases of amaranth such as leaf blight, damping-off, and root rot. As a causal agent of soft rot disease, Pectobacterium spp. could infect various plant species. In this study, we isolated the bacterial pathogen causing soft rot of amaranth in South Korea. In Gangneung, Gangwon province during 2017, amaranth plants showed typical soft rot symptoms such as wilting, defoliation and odd smell. To isolate pathogen, the macerated tissues of contaminated amaranth were spread onto LB agar plates and purified by a single colony subculture. One ml bacterial suspension of a representative isolate was injected to the stem of five seedlings of 2-week-old amaranth with a needle. Ten mM magnesium sulfate solution was used as a negative control. 16S rDNA gene and recA gene were sequenced and compared with the reference sequences using the BLAST. In the phylogenetic tree based on 16S rDNA gene and recA gene, GSA1 strain was grouped in Pcb.

• 생물환경조절학회지
• /
• 제6권4호
• /
• pp.317-323
• /
• 1997

Erwinia rarotovora subsp carotovora에 의한 콩나물 무름병 발생을 인위적인 조건하에서 조사하였다. 콩나물의 재배 온도가 콩나물 무름병 발생과 생장에 미치는 영향은 3$0^{\circ}C$이상의 고온에서 무름병 발생율이 높아졌으며 35$^{\circ}C$에서는 약 22%의 발병율을 나타내었다. 종피와 자엽 부위에 인위적인 상처를 낸 경우 70%이상의 발병율을 보였으며 콩나물의 신장을 억제하였다. 습도는 90%이상 유지시 33%의 발병율을 보였으며 콩나물의 생장을 억제시켰다. 콩나물 재배 배출액을 관수액으로 재이용하였을 때 무름병의 발병율이 증가하였다.

• 한국식물병리학회지
• /
• 제14권6호
• /
• pp.741-743
• /
• 1998

A bacterial disease of pepper (Capsicum annuum L.) that rooted the stem nodes to black was found in pepper plants which cultivated in plastic house at Chungdo, Kyungpook, Korea in March, 1998. Bacterial isolates derived from the diseased peppers were pathogenic to potato, eggplant and Chinese cabbage but, was not pathogenic to chrysanthemum by artificial inoculation. On the basis of bacteriological characteristics and pathogenicity test on host plants, the causal organism of the node soft rot of pepper is identified as Erwinia carotovora subsp. carotovora and the name of disease is proposed as bacterial node soft rot of pepper.

• 식물병연구
• /
• 제6권1호
• /
• pp.1-5
• /
• 2000

• 식물병연구
• /
• 제29권1호
• /
• pp.64-71
• /
• 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.

• 식물병연구
• /
• 제29권4호
• /
• pp.445-451
• /
• 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.

• 식물병연구
• /
• 제29권4호
• /
• pp.452-458
• /
• 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.

• 한국식물병리학회지
• /
• 제13권1호
• /
• pp.13-17
• /
• 1997

A causal agent of bacterial soft rot occurring in soybean sprout cultivation in Korea was isolated and identified, and its incidence in several sprout-soybean cultivars was examined. Infected soybean seeds became light brown and whitish, and could not germinate until 3 days after seeding, accompanying rotting of soybean seeds and sprouts. The causal organism isolated from the rotten seeds and sprouts was identified as Erwinia carotovora subsp. carotovora on the basis of its pathogenicity, morphological and physiological characteristics and the results of the Biolog GN microplate test program. The bacterial soft rot by E. c. subsp. carotovora was firstly described in soybean sprout in Korea, and we name it“the bacterial soft rot of soybean sprout”. The disease occurred more frequently in Nam-hae and Fu-reun sprout-soybean cultivars than in Eun-ha, So-baek, and Ik-san cultivars.

• 원예과학기술지
• /
• 제30권2호
• /
• pp.137-143
• /
• 2012

Chinese cabbage plant was grown hydroponically for 4 weeks in order to examine the temporal relationship of calcium concentration of the nutrient solution with calcium content in the leaf tissue and susceptibility of the tissue to soft rot disease by $Pectobacterium$ $carotovorum$ ssp. $carotovorum$ (Pcc). Calcium concentration from 0.5 to 32.0 mM was maintained for 1 week using Hoagland & Arnon solution. The calcium content of the leaf was proportionally increased to the concentration of the nutrient in the solution (r = 0.912). In contrast, the severity of soft rot symptom in the young leaves was inversely related with the amount of calcium supplied to the nutrient solution (r = 0.899). Water-soluble chitosan, prepared by hollow fiber filtration (> 100 kDa) was applied into the nutrient solution from 0.0 to 5,000 ppm. The chitosan of 10 ppm was the most effective to promote calcium uptake of the leaf, showing 155% of the control. The same chitosan solution prohibited most soft rot development of the leaf by Pcc, exhibiting only 53% of the control. Among different molecular weight fractions, chitosan fraction obtained from 30-100 kDa molecular weight cut-off promoted calcium uptake the most up to 163% of the control, and reduced the development of soft rot disease recording merely 36% of the control of the leaf tissue. The results obtained in the present study suggest that large scale production of water-soluble chitosan with an optimum molecular weight and its commercial application to Chinese cabbage production will be important to improve yield and quality of the crop.

• 한국식물병리학회지
• /
• 제10권3호
• /
• pp.157-162
• /
• 1994

Erwinia rhapontici causes soft-rot disease in a number of plants such as onion, garlic and hyacinth. There has been no report that E. rhapontici produces pectate lyase. Pel gene was cloned from genomic DNA of the parasitic soft-rot E. rhapontici polymerase chain reaction by using synthetic oligonulceotide primers designed from the pel 1 to E. carotovora. The recombinant plasmid pJE101 containing pectate lyase gene, when introduced into E. coli DH5$\alpha$, produced pectate lyase an macerated hyacinth tissue.