Some plant pathogenic bacteria species are environmentally high-risk organisms that have a negative impact on agricultural production. Experiments with these pathogens in a biosafety laboratory require safety protocols to prevent contamination from these pathogens. In this work, we investigated the efficacy of using UV-C irradiation for the purpose of sterilizing an important plant pathogenic bacterium, Erwinia pyrifoliae, in a laboratory setting. For the test, the pathogen (1.71 × 108 CFU/ml) was inoculated on the surface of Potato Dextrose Agar (PDA) and the inoculated media were placed on a work surface in a biosafety cabinet (Class 2 Type A1) as well as on three different surfaces located within the laboratory: a laboratory bench, a laboratory bench shelf, and the floor. All the surfaces where the media were placed were in range of the UV-C beam projected by the UV lamp installed in the ceiling of the BSL 2 Class biosafety laboratory. Measurements of the reduction rate of bacteria under UV-C irradiation were conducted at different time intervals: after 10 minutes, 30 minutes, 1 hour, 2 hours, and 3 hours, respectively. The reduction rate of bacteria ranged from 90% to 99% after 10min irradiation, from 97.8% to 100% after 30 minutes of irradiation, from 99.1% to 100% after 1 hour of irradiation, and from 99.99% to 100% after 2 hours of irradiation. After 3 hours of irradiation, the pathogen was completely killed in all the test conditions. In the cases of the laboratory bench and the shelf of the laboratory bench, the effectiveness of UV-C irradiation differed slightly between the site where the bacteria located vertically under the lamp and the site where the bacteria were located 1 meter away horizontally from the site under of the lamp.

High-risk microbial pathogens are handled in a biosafety laboratory. After experiments, the pathogens may remain as contaminants. To safely manage a biosafety laboratory, disinfection of microbial contaminants is necessary. This study was carried out to evaluate the effect of UV-C irradiation for the disinfection of a high-risk plant pathogenic bacterium Erwinia amylovora in a laboratory setting. For the test, the bacterium (8.7 × 106 CFU/ml) was embedded on the surface of PDA and placed on the work surface in a biosafety cabinet (Class 2 Type A1), and on the three different surfaces of the laboratory bench, laboratory bench shelf, and the floor which were positioned in a straight line from the UV lamp installed in the ceiling of the biosafety laboratory (BSL 2 class). UV-C irradiation was administered for 10min, 30min, 1 hr, 2hr, 3 hr, and 4hr, respectively. The reduction rate of bacteria ranged from 95% to 99% in regard to 10 min irradiation, from 97% to 99% in regard to 30 min irradiation, from 99.8% to 99.9% in regard to 1 hr irradiation, and higher than 99.99% in regard to 2 hr irradiation. The bacterium was completely inactivated after 3 hr irradiation. A similar UV-C irradiation effect was obtained when the bacterium was placed at a distance of 1 m from the three different surface points. Bacterial reduction by UV-C irradiation was not significantly different among the three different surface points.

This study was conducted to obtain basic information for the use of the ATP fluorescence detection method in consideration of the most common and frequent contamination situation that occurs in laboratories dealing with fire blight causing bacterium, Erwinia amylovora. ATP luminescence measurements (Relative Light Unit, RLU) were tested against these pathogen cells (CFU/cm2) which were artificially introduced on the disinfected surface of a bench floor of a biosafety cabinet (Class 2 Type A1), on a part of the disinfected surface of a lab experimental bench, on a part of the disinfected floor, and on a part of the disinfected floor of an acryl chamber for bioaerosol studies in a biosafety laboratory (BSL 2 class) using two different ATP bioluminometers. RLU values were not much increased with the bacterial cells from 2.15 × 102/cm2 to 2.15 × 106/cm2. RLU values varied among the four different surfaces tested. RLU values measured from the same number of bacterial cells differed little between the two different ATP bioluminometers used for this study. RLU values obtained from bacterial cells higher than 2.15 × 107/cm2 indicated the presence of bacterial contamination on the four different surfaces tested. The R2 values obtained based on the correlation data for the RLU values in response to different E. amylovora cell numbers (CFU/ cm2) on the surfaces of the four test spots ranged from 0.9827 to 0.9999.

화상병균(Erwinia amylovora)에 의해 발생하는 과수 화상병은 주로 사과, 배 등의 장미과 식물에서 발병한다. 과수 화상병은 국내에서 금지 병원균으로 지정되어 있으며, 2015년 경기도 안성의 배과수원에서 최초 발견되었다. 그러나, 현재까지 근본적인 방제약제가 없는 상황으로 발생지는 매몰이 최선의 방법으로 여겨진다. 따라서 본 연구에서는 2019년을 기준으로 충북지역의 과수 화상병 발생 원인 분석을 통하여 발생 경로 차단을 위한 역학조사를 실시하였다. 1. 충주시 등 3개 시군의 전체 221농가 141ha에서 과수 화상병이 발생하였으며, 세부적인 연도별 발생현황은 2015년(2농가 1ha), 2018년(74농가 51.5ha), 2019년(145농가 88.9ha) 로 나타났다. 2. 과수 화상병의 발생시기는 주로 5월부터 8월 사이로 나타났으며, 특히 6월(73.8%)이 가장 많이 발생하였으며, 7월 (17.2%), 5월(7.6%), 8월(1.4%)순으로 나타났다. 3. 과수 화상병 발생 의심 신고 후 확진 매몰까지 소요기간은 11.9일이었고, 발생에서 매몰까지의 기간은 최단 5일에서 최장 19일로 조사되었다. 4. 병원균의 최초 발생지로부터의 확산 거리는 평균 21 km로 나타났으며 가장 먼거리는 음성군 비산면으로 34 km였다.

Bacterial soft rot is one of the major disease of Zantedeschia species (Calla lily) caused by Erwinia carotovora. The objectives of this study were i) to screen the most efficient method to determine resistance level against E. carotovora and ii) to evaluate the genetic variability in Zantedeschia genotypes by inoculation of Ecc NHRI-3 and PD 1784 isolates. Four screening tests i.e. leaf disk, petiole, tuber and tuber slice tests were used to determine the resistance level in calla lily. Eleven genotypes from section Zantedeschia were used for variation studies against E. carotovora by using the leaf disk test. It was observed that all genotypes showed variation in resistance level and could be categorized in 3 groups on the basis of their resistance level. Four of the genotypes were resistant against this pathogen whereas, 6 genotypes were moderately resistant and only one genotype was found susceptible. Within section Aestivae, ‘Galaxy’, ‘Florex Gold’, ‘Treasure’ and ‘Mango’ were found very susceptible cultivars, whereas ‘Coral Sunset’, ‘Hazel Marie’ and ‘Neroli’ were less susceptible genotypes. Most of the cultivars from section Aestivae were susceptible to bacterial soft rot and the cultivar ‘Florex Gold’ was identified as susceptible control. It is suggested to perform pre-screening through leaf disk method which proved to a non-destructive test. The pre-screening evaluation can discriminate susceptible cultivar and resistant cultivar. Tuber slice test is more useful in screening subsequent genotypes at a later growth stage in any breeding program.

Erwinia herbicola(EH) 채소 연부병 방제를 위하여 충북 청원군, 진천군 및 충남 연기군 일원의 채소 경작지 토양으로부터 형광성을 나타내는 Pseudomonas속 1, 196균주를 선발하고, 연부병균 Erwinia herbicola에 대한 생육억제력과 생물학적 검정으로 발병억제력이 강한 2균주를 선발하여 Pseudomonas fluorescens S4(PS4)와 Pseudomonas fluorescens S65 (PS65)로 동정하였다. 배춧잎을 이용하여 분리길항균의 연부병균에 대한 생물학적 억제력을 확인한 결과 상당한 발병억제력을 확인하였다. 이들 두 균주가 가장 높은 길항력을 나타내는 조건은 배양 초기배지의 pH를 7.0으로하여 25℃에서 3일간 배양했을 때였다. 화학농약 및 항생물질에 대해 2균주 모두 benomyl, propamocab hydrochloride, fosethyl-Al-folpet, vancomycin, penicillin 및 lincomycin에 내성을 나타냈고, PS4균주는 erythromycin에 대해서도 내성을 나타냈다.

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.

인삼 조사포닌과 인삼즙액이 인삼 근부패를 일으키는 병원균 Fusarium solani와 Erwinia carotovora의 생장과 증식 및 포자발아에 미치는 영향을 조사하여 다음과 같은 결과를 얻었다. 1. 인삼 조 Saponin의 농도가 증가됨에 따라 F. solani의 대형분생포자의 발아율은 억제 되었으며 500 ppm 이상 첨가시 현저하게 억제 되었다. 2. 토양 추출액은 초기에 F. solani의 포자 발아를 억제하는 효과가 있었으나 24시간후에는 무효화되었다. 3. 인삼 조 Saponin의 첨가 농도가 증가됨에 따라 F. solani의 포자형성량이 감소되었으며 고체배지에서 이러한 현상은 더욱 뚜렷하게 나타났다. 4. 인삼 Saponin을 첨가 했을시 균사생장량은 약간 감소되었으나 농도에 따른 감소율은 인정되지 않았다. 5. 인삼 조 사포닌은 농도가 증가 될 수록 F. solani의 Colony 형성을 억제하였으나 인삼즙액은 농도가 증가될수록 현저하게 F. solani의 Colony수를 증가시켰다. 6. 인삼 조 Saponin과 인삼즙액 모두 E. carotovora의 생장을 촉진시켰다.