Effect of Producing Different Phenazines on Bacterial Fitness and Biological Control in Pseudomonas chlororaphis 30-84

유준명,Dongping Wang,Leland S. Pierson III,Elizabeth A. Pierson 한국식물병리학회 2018 Plant Pathology Journal Vol.34 No.1

Pseudomonas chlororaphis 30-84 is a biological control agent selected for its ability to suppress diseases caused by fungal pathogens. P. chlororaphis 30-84 produces three phenazines: phenazine-1-carboxylic acid (PCA), 2-hydroxy-phenazine-1-carboxylic acid (2OHPCA) and a small amount of 2-hydroxy-phenazine (2OHPHZ), and these are required for fungal pathogen inhibition and wheat rhizosphere competence. The two, 2-hydroxy derivatives are produced from PCA via the activity of a phenazine-modifying enzyme encoded by phzO. In addition to the seven biosynthetic genes responsible for the production of PCA, many other Pseudomonas strains possess one or more modifying genes, which encode enzymes that act independently or together to convert PCA into other phenazine derivatives. In order to understand the fitness effects of producing different phenazines, we constructed isogenic derivatives of P. chlororaphis 30-84 that differed only in the type of phenazines produced. Altering the type of phenazines produced by P. chlororaphis 30-84 enhanced the spectrum of fungal pathogens inhibited and altered the degree of take-all disease suppression. These strains also differed in their ability to promote extracellular DNA release, which may contribute to the observed differences in the amount of biofilm produced. All derivatives were equally important for survival over repeated plant/harvest cycles, indicating that the type of phenazines produced is less important for persistence in the wheat rhizosphere than whether or not cells produce phenazines. These findings provide a better understanding of the effects of different phenazines on functions important for biological control activity with implications for applications that rely on introduced or native phenazine producing populations.

Development of the Droplet Digital PCR Method for the Detection and Quantification of Erwinia pyrifoliae

Lin He,김성환,유준명 한국식물병리학회 2023 Plant Pathology Journal Vol.39 No.1

Black shoot blight disease caused by Erwinia pyrifoliae has serious impacts on quality and yield in pear production in Korea; therefore, rapid and accurate methods for its detection are needed. However, traditional detection methods require a great deal of time and fail to achieve absolute quantification. In the present study, we developed a droplet digital polymerase chain reaction (ddPCR) method for the detection and absolute quantification of E. pyrifoliae using a pair of species-specific primers. The detection range was 103- 107 copies/ml (DNA templates) and cfu/ml (cell culture templates). This new method exhibited good linearity and repeatability and was validated by absolute quantification of E. pyrifoliae DNA copies from samples of artificially inoculated immature pear fruits. Here, we present the first study of ddPCR assay for the detection and quantification of E. pyrifoliae. This method has potential applications in epidemiology and for the early prediction of black shoot blight outbreaks.

식물병원체 안전정보집(pathgen safety data sheet) 제작현황

김성환,최창원,최형우,유준명 한국버섯학회 2023 버섯 Vol.27 No.2

꽃감염 위험기간 중의 강우가 충남지역 과수 화상병 발병에 미치는 영향

김병련,김윤정,원미경,주정일,유준명,이용환 한국농림기상학회 2023 한국농림기상학회지 Vol.25 No.4

과수의 개화기 꽃감염 위험기간 중의 강우가 화상 병의 발병에 어느 정도 영향을 주었는지 조사하였다. 2015년부터 시작된 충남지역의 과수 화상병 발병 기간 중에서 2020년부터 2022년의 발병 규모가 가장 크게 변화하였는데, 2020년에는 63개 과원에서 발병하였고, 2021년에는 170 과원으로 크게 증가하였으나, 2022년에 46개 과원으로 감소하였다. 2022년에는 발병과원의 발병 나무 가지에 형성된 궤양증상이 감소하였고, 이것은 개화기 건조한 날씨에 의한 것으로 평가 되었다. 즉, 꽃감염 위험기간 중의 강우 여부 및 누적 강수량에 따라 그 해의 화상병 발병은 증가하거나 감소하였다. 이러한 경향은 사과와 배가 재배되는 조사 지역 모두에서 유사한 경향이었고, 꽃감염 위험시기의 기상환경 중 강우는 월동 궤양으로부터 활성화된 병원균의 전반과 꽃 감염에 큰 영향을 주었으며, 특히 꽃감염 위험경보가 시작되는 초기 3일간의 강수량은 발병 규모를 결정하는 요인으로 확인되었다. In this study, the extent of the impact of rainfall on the outbreak of fire blight during the blossom infection risk period was explored. In the Chungnam province, the outbreak of fire blight disease began in 2015, and changes in the outbreak’s scale were most pronounced between 2020 and 2022, significantly escalating from 63 orchards in 2020 to 170 orchards in 2021, before decreasing to 46 orchards in 2022. In 2022, the number of incidence has decreased and the number of canker symptom in branches has also decreased. It was evaluated that the significant decrease of fire blight disease in 2022 was due to the dry weather during the flowering season. In other words, this yearly fluctuation in fire blight outbreaks was correlated with the presence or absence of rainfall and accumulated precipitation during the blossom infection risk period. This trend was observed across all surveyed regions where apples and pears were cultivated. Among the weather conditions influencing the blossom infection risk period, rainfall notably affected the activation of pathogens from over-wintering cankers and flower infections. In particular, precipitation during the initial 3 days of the blossom infection risk warning was confirmed as a decisive factor in determining the outbreak’s scale.

Occurrence of black shoot blight in apple and pear trees in Korea

이미현,이용환,이성찬,최효원,양미숙,문제선,권석윤,유준명 충남대학교 농업과학연구소 2023 Korean Journal of Agricultural Science Vol.50 No.4

Erwinia pyrifoliae, which causes black shoot blight in apple and pear trees, was first identified in Korea in 1995. Extensive measures are typically used to control the disease by eradicating trees in diagnosed orchards, owing to the detrimental impact of the disease on apple and pear production. However, despite governmental efforts, the disease has continuously spread. In this study, we analyzed the current status of the black shoot blight occurrence in apple and pear orchards between 1995 to 2022. Our findings reveal that over the past 28 years, black shoot blight has occurred in 26 cities and districts across five Korean provinces. The affected regions are predominantly concentrated in the northern part of Korea, including the Gangwon and Gyeonggi provinces. Furthermore, black shoot blight has gradually expanded to the northern provincial regions of Chungbuk, Chungnam, and Gyeongbuk, which are centrally situated in Korea. Furthermore, the occurrence pattern of black shoot blight differed between apple and pear orchards; in apple orchards, black shoot blight occurred consistently each year, with a sudden increase in cases in 2020; however, in pear orchards, it has considerably decreased since 2007. To the best of our knowledge, this is the first comprehensive report on the occurrence of black shoot blight in apple and pear trees in 28 years, and the results will provide valuable insights for future disease management strategies.

한국식물병명목록 6.1판(2023 개정본)

김선희,최재혁,최영준,박병용,이수헌,김경희,공현기,김동근,김순옥,김영호,백창기,변희성,서장균,유준명,윤주연,이동현,이승열,임승모,전용호,전재용,최인수,최인영,최효원,홍진성,홍승범,Seon-Hee Kim,Jaehyuk Choi,Young-Joon Choi,Byeong-Yong Park,Su-Heon Lee,Gyoung Hee Kim,Hyun Gi Kong,D 한국식물병리학회 2023 식물병연구 Vol.29 No.4

한국식물병명목록 6판이 2022년 4월에 발행된 이후에 1년이 경과하였다. 목록 6판에서 발견된 오류사항을 수정하고 6판 이후에 보고된 병을 추가하여 한국식물병명목록 6.1판(2023)을 작성하였다. 기존 6판의 수정사항은 397건으로 대부분은 단순 오탈자나 경미한 사항이었으나, 12개의 병은 중복이나 근거가 명확하지 않아 삭제하였고, 2개의 병은 병명을 바꾸었다. 2021년 이전에 보고되었으나 6판에 수록되지 않았거나, 6판 발행 이후에 보고된 158개의 병을 추가하였다. 결국 목록 6.1판에는 6판에 보고된 병 6,534개에 146개 병이 추가되어 총 6,680개의 병이 수록되었다. 기주 분류군도 30개가 더해져 목록 6판의 1,390개에서 6.1판에는 1,420개가 되었다. 병원체는 목록 6판의 2,400개에서 62개가 더해져 6.1판에는 2,462 분류군이 되었다. 결국 한국식물병명목록 6.1판(2023)은 1,420개의 기주에, 2,462 분류군의 병원체가 일으키는 6,680개의 병을 수록하고 있다. 목록 6.1판은 책으로 인쇄되지는 않고 온라인 한국식물병명목록(https://genebank.rda.go.kr/kplantdisease.do)을 통하여 제공되고 있다. More than a year has passed after the 6th edition of 'List of Plant Diseases in Korea (LPDK)' was published in April 2022. The 6.1st edition (2023) of List of Plant Diseases in Korea was made by correcting errors found in the 6th edition of list and adding new diseases reported after the 6th edition. There were 397 corrections from the 6th edition, most of which were simple spelling errors or minor issues. However, 12 diseases were deleted due to duplication or unclear literature proof, and 2 diseases had their diseases' common names changed. We added 158 diseases that were reported before 2021 but not included in the 6th edition, or reported after the 6th edition. After all, 146 diseases were added to the 6,534 diseases in the 6th edition, resulting in a total of 6,680 diseases in the 6.1st edition. Thirty host taxa were also added, increasing the number from 1,390 in the 6th edition to 1,420 in the 6.1st edition. Pathogens were also added to 62 taxa, from 2,400 in the 6th edition, bringing the total to 2,462 taxa in the 6.1st edition. Ultimately, the 6.1st edition (2023) of 'The List of Plant Diseases in Korea' contains 6,680 diseases caused by pathogens of 2,462 taxa on 1,420 hosts. The 6.1st edition is not printed as a book, but is provided through the online 'List of Plant Diseases in Korea' (https://genebank. rda.go.kr/kplantdisease.do).