Bacterial phytopathogen Pectobacterium causes soft rot disease in several vegetable crops globally, resulting in heavy agricultural losses at both the pre and postharvest stages. The present work was carried out to screen Kimchi cabbage genetic resources conserved at the National Agrobiodiversity Center, Rural Development Administration, Korea, for resistance against the soft rot pathogen Pectobacterium carotovorum subsp. carotovorum KACC 21701 over a period of three years (from 2020 to 2022). Infection of the phytopathogen was carried out at four-leaf stage and for each accession, twenty-five plants per germplasm were infected with KACC 21701. Kimchi cabbage cultivars Wangmatbaechu, Seoulbaechu, and CR Kiyoshi were used as control. Seven-days post-infection, the Disease Index (DI) values were manually recorded from zero to four, zero matched perfectly heathy plants and four completely dead plants. The 682 accessions of Kimchi cabbage exhibited varying degrees of disease resistance to KACC 21701 and thirty accessions, exhibiting a DI≤2, were considered for replication studies. During the replication studies, four landrace germplasms (IT102883, IT120036, IT120044, and IT120048) and one cultivar (IT187919) were confirmed to be moderately susceptible to KACC 21701. Results of the preliminary screening as well as replication studies were documented for the all the 682 germplasms. Addition of such information to the passport data of stored germplasms might serve as potential bio-resource for future breeders and researchers to develop resistant varieties or study the mechanisms involved in resistance of plants to such phytopathogen.

The bacterial soft-rot disease is one of the most critical diseases in vegetables such as Chinese cabbage. The researchers isolated two bacteria (Pseudomonas kribbensis and Pantoea vagans) from diseased tissue samples of Chinese cabbages and confirmed them as being the strains that cause soft-rot disease. Lactic-acid bacteria (LAB), were screened and used to control soft-rot disease bacteria. The researchers tested the treatments with hypochlorous acid water (HAW) and LAB supernatant to control soft-rot disease bacteria. The tests confirmed that treatments with the HAW (over 120 ppm) or LAB (Lactobacillus plantarum PL203) culture supernatants (0.5 mL) completely controlled both P. kribbensis and P. vagans.

백색칼라 ‘White Heart’는 2013년 국립원예특작과학원에서 육 성하였다. 절화수량이 많은 Zantedeschia aethiopica ‘Childsiana’ 와 무름병에 강하지만 수량이 적은 Zantedeschia aethiopica ‘Wedding March’를 2004년 교배하였다. 2005년부터 2007년까지 구근증식과 양성을 거쳐 2008년부터 2012년 4년간 1, 2차 생육과 개화특성을 평가하여 화형이 우수하고 무름병에 저항성이 있는 ‘Z. cw-116’를 선발하였다. 2013년에 ‘원교 C4-8호’로 계통명을 부여하여 3차 특성검정 및 기호도 평가를 수행한 결과, 화형이 우수하고 무름병에 강한 계통으로 평가되었다. 2013년에 직무육 성품종심의회를 통과하여 ‘White Heart’로 명명 받았다. ‘White Heart’의 생육 및 개화특성은 부본으로 사용된 ‘Wedding March’을 대비품종으로 하여 조사하였다. ‘White Heart’는 초장 73cm, 엽장 27cm로 부본과 비슷하나, 꽃이 더 크고 둥글며 예쁜 백색(RHS color chart, W155C) 중형의 절화용 품종이다. 주당 화수는 1.4개 로 대조품종보다 약간 많으며 꽃대길이가 61cm로 대조품종 (74cm)보다 짧은 편이다. 절화수명은 13일(대조 12일)로 약간 길며 무름병에는 강한 저항성을 갖고 있다.

Soft rot caused by Pectobacterium carotovorum subsp. carotovorum is a destructive disease of the fleshy storage tissues of vegetables and ornamentals that occurs worldwide. This study was carried out to find an effective method for evaluating soft rot disease on a massive scale in greenhouse and to screen resistant accession for the disease with lettuce germplasm. Spray method with 5 mL suspension of 109 colony formation unit per milliliter (CFU/mL) of P. carotovorum subsp. carotovorum per plant at the 6 ~ 7 foliage leaf stage was the most effective to evaluate soft rot disease. We evaluated resistance to soft rot using this method for 812 accessions of lettuce germplasm introduced from 52 countries. As the results, withered rates for each germplasm accession ranged from 0 to 100 percent and among 812 accessions of lettuce germplasm investigated, 21 accessions showed very high resistance. Among the 21 accessions, 11 accessions were from Korea, each 2 accessions were from USA and Israel, and each 1 accession was from Afghanistan, Germany, Hungary, Netherlands, Pakistan, and Uzbekistan. Accessions from Israel, Syria, and Afghanistan showed high resistance level. Among very high resistant 21 accessions, 12 were landraces, 6 were cultivars, and 3 were wild relatives. The 21 accessions were consisted of 12 leaf lettuce, 5 romaine type, 3 wild relatives, and 1 butterhead lettuce. Leaf lettuce accessions showed the highest resistance level while crisphead lettuce accessions had the lowest resistance level among the cultivated lettuce types. Wild relatives had greater resistance than landraces and cultivars. These accessions which resistance to soft rot will be used for soft rot resistance breeding program in lettuce.

네덜란드와 미국에서 최근에 육성된 절화 및 분화용26품종을 도입하여 무름병저항성 및 개화특성을 평가하였다. 국립원예특작과학원 무가온 비닐하우스내에서 여름재배시 무름병발생 및 생육, 개화특성을 조사한 결과, 무름병은 ‘Picasso’, ‘Dark Eyes’, ‘Murano’가 포장발병율이낮고, 저항성에도 강한 것으로 나타났다. 특히 ‘Picasso’는 포장발병율이 5.8%로 가장 낮았고, 잎절편상처접종법에서도 0.3으로 가장 강한 저항성을 나타냈다. 기형화 발생 수는 ‘Sienna’가 주당 1.6개로 가장 많았고, ‘IntimateIvory’, ‘Pillow Talk’에서는 발생하지 않았다. 개화소요일수는 33일로 ‘Amigo’, ‘Mistral’이 평균 32.6일과 32.8일로 가장 빨랐고 가장 늦은 품종은 ‘Prado’로 75.6일이소요되었다. ‘Aquila’, ‘Tyris’는 절화용 품종으로 주당 절화수량이 각각 평균 4.2개와 4.4개로 많은 다수성 품종이나, 기형화 발생이 많고 무름병에 감수성이었다. ‘PillowTalk’, ‘Mistral’과 ‘Picasso’는 주당 화수가 많을 뿐 아니라 개화까지 소요일수가 짧아 절화분화 겸용으로의 활용도가 높은 것으로 평가되었다. 또한 화경장이 26cm 내외로 짧은 ‘Callifornia Red’와 ‘Tuno’ 등은 분화용으로활용할 수 있을 것으로 평가되었다.

Calla lily is a mainstream floricultural crop but itscommercial success is limited by severe susceptibility to softrot. This disease can be controlled to some extent by imple-menting appropriate cultural practices but developing resis-tant cultivars against this pathogen is the most promisinglong-term strategy. The purpose of this work was to developnew cultivars resistant to this bacterial disease by initiatingan appropriate breeding programme. Field observations of120 resistant lines selected by a leaf-disk susceptibility testwere carried out and survival rates were measured. Twolines were selected after further evaluation of resistancelevel, flowering characteristics and following guidelines forconduct of tests for distinctness, homogeneity, and stability.Further preference testing of the selected lines by growers,consumers, researchers and agricultural advisors was car-ried out with excellent results. The selected new lines are‘Silky White’ and ‘Mont Blanc’ which emerge as the first,soft-rot resistant calla lily cultivars from our breeding program.

Mushroom is cultivated in many areas of the Korea as one of the major economical crops. The production areas have steadily increased approximately 3,674 ha in 2002 to 4,118 ha in 2005. Several bacteria have been known as the causal agents of certain diseases of cultivated button mushroom, Agaricus bisporus, and oyster mushroom, Pleurotus ostreatus. It is well known as bacterial diseases of the cultivated mushroom such asbrown blotch, mummy disease, bacterial pit, bacterial rot and weeping disease, ginger blotch, and drippy gill. Unknown soft rot bacterium was isolated from sunken browning symptom of cultivated oyster mushrooms grown in Korea. The symptoms are appear as a sunken browning lesions on the caps of affected mushrooms. The bacterium causes a rapid soft rot of cultivated mushrooms in comparison with brown blotch bacteria at temperatures above 25℃. From these lesions we isolated one bacterial strain (designated OM1). Inoculation of bacterial isolates into mushroom caps yielded characteristic sunken brown, watersoaked and severe soft rot symptoms, but which were indistinguishable in early stage from those of the bacterial brown blotch well known to mushroom growers. Results of Gram stain and biochemical tests identified this isolate as Burkholderia gladioli pv. agaricicola. This was confirmed by pathogenicity, physiological and biochemical characteristics, and results of an analysis of the 16S rRNA gene sequences and the fatty acids profile. This is the first report of the isolation of B. gladioli pv. agaricicola from cultivated oyster mushroom in Korea.

Erwinia rarotovora subsp carotovora에 의한 콩나물 무름병 발생을 인위적인 조건하에서 조사하였다. 콩나물의 재배 온도가 콩나물 무름병 발생과 생장에 미치는 영향은 30℃이상의 고온에서 무름병 발생율이 높아졌으며 35℃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.

감자 괴경에 타박상을 입혔거나 세균현탁액을 주입했을 때 낮은 water potential(-6.46 bar) 보다 높은 water potential (-6.06 bar)에서 더 쉽게 부패를 초래하였으며, 높은 water potential을 가진 괴경과 낮은 water potential을 가진 괴경 사이에 있어서의 부패의 진전에는 큰 차이를 발견할 수 있었으며, 현탁액의 농도의 종류에 따른 괴경의 연부병의 이병정도는 높은 water potential에서 높았으며, 세균 현탁액 농도의 은 높은 water potential에서 이며 낮은 water potential에 서는 이었으며, 높은 water potential과 낮은 water potential 에서는 작은 차이를 인정할 수 있었다. 이 시험에서 감자는 상처나 타박상이 나지 않도록 다루어야 하며 수확후 충분히 건조하여야 오랜 운반과 저장중에 연부병 발생을 크게 줄일 수 있다는 것을 나타낸다.

Pectobacterium carotovorum subsp. carotovorum was found to be highly virulent to various vegetables, including Chinese cabbage. The antibacterial isolate CAB12243-2 was tested in a field bioassay for suppressing soft rot disease. The nucleotide sequencing of the 16S rRNA gene identified, the CAB12243-2 strain used in this study as Bacillus toyonensis. B. toyonensis CAB12243-2 inhibited the pectate lyase process by soft rot pathogens, and used trehalose and glucose as carbon sources. In field tests, the antibacterial isolate B. toyonensis CAB12243-2 suppressed soft rot disease with 73.0% control efficacy on the spring cultivar “Norangbom” and with 68.9% efficacy on the fall cultivar “Bulam 3”. These results suggest that B. toyonensis CAB12243-2 can be used as a biological control agent for the control of soft rot diseases on vegetables.

The SS (Bacillus subtilis 10%), WS (Microbial extract 70%), and DS (Sulfur 78%) agents were selected by mycelial growth inhibitory effect test against kiwifruit soft rot pathogen (B. dothidea) with 11 kinds of environment-friendly agricultural materials on PDA medium for 10 days. They showed at 94.2%, 65.2%, 58.9%, respectively. The control value of WS and SS agents were better than DS in storage experiment. It was effective SS and WS single application, DS-WS and WS-SS alternate application in the field trial.

We performed field trials to assess levels of changes in intrinsic properties and resistance against soft rot of the potato cultivar ‘Irish Cobbler’ upon the introduction of the Shiva-1 gene. Each five lines, transformed with Shiva-1 gene controlled by the PAL5 promoter (P) and by the CaMV 35S promoter (E) were evaluated in the field. In based on evaluation of 10 defined morphological characteristics, all the transgenic clones of both lines proved to be true to type. When five agronomic characteristics were taken into account as well, all the transgenic lines except E8 were considered to be true to type. According to the result of northern blot analysis, seven (P1, P3, P4, P6, E10, E12, and E16) transgenic clones could be distinguished clearly from corresponding untransformed clones. But in three lines (P8, E5, and E8), no hybridization signal was detected. There seems to be positive correlation between the levels of resistance to soft rot and the transgenic expression at mRNA levels in P lines. But in the case of E lines, however, there doesn’t seem to be any correlation between the levels of disease resistance and mRNA expression