溶果膠細(xì)菌能夠引起馬鈴薯黑脛病和其他重要植物軟腐病,嚴(yán)重影響食品的質(zhì)量和產(chǎn)量,阻礙經(jīng)濟發(fā)展。本研究的目的主要是分離鑒定肯尼亞Nakuru地區(qū)感染馬鈴薯的溶果膠細(xì)菌,并針對分離的溶果膠細(xì)菌來分離裂解性噬菌體,從而探究合適的噬菌體混合制劑防治馬鈴薯軟腐病。首先,從Nakuru的Molo和Mau Narok地區(qū)的不同農(nóng)場收集有軟腐病病癥的馬鈴薯塊莖,用結(jié)晶紫果膠酸鹽培養(yǎng)基培養(yǎng)并分離病原菌,共獲得71株病原菌。致病性測試結(jié)果顯示其中的36株病原菌能浸染馬鈴薯塊莖。用PCR擴增這36株致病菌的16S rDNA,通過測序?qū)χ虏【M行初步鑒定,再用BIOLOG微生物鑒定儀進行精準(zhǔn)鑒定。鑒定結(jié)果顯示36株致病菌中有20株軟腐果膠桿菌亞種carotovorum,7株熒光假單胞菌B和9株熒光假單胞菌A,用特異性引物Y1和Y2擴增出了20株軟腐果膠桿菌的果膠裂解酶編碼基因,進一步證明了這20株致病菌為軟腐果膠桿菌。以這20株軟腐果膠桿菌作為目標(biāo)菌株,從湖北省武漢市周邊采集的土壤和污水中分離到11株噬菌體,其中有7株來屬于肌尾噬菌體科,4株屬于長尾噬菌體科。通過監(jiān)測噬菌體和細(xì)菌懸液OD600的變化和一步生長曲...

【文章頁數(shù)】：87 頁

【學(xué)位級別】：碩士

【文章目錄】：
摘要
ABSTRACT
CHAPTER ONE: INTRODUCTION
    1.1 Background of the study
    1.2 Literature review
        1.2.1 Importance of the Potato
        1.2.2 Pectolytic bacterial pathogens of potatoes
        1.2.3 Bacteriophages
    1.3 Problem statement
    1.4 Justification
    1.5 Objectives
    1.6 Hypotheses
CHAPTER TWO: ISOLATION AND CHARACTERIZATION OF PECTOLYTIC BACTERIAL PATHOGENS INFECTING POTATOES
    2.1 Materials and methods
        2.1.1 Bacterial isolation and culture conditions
        2.1.2 Pathogenicity tests
        2.1.3 Pectolytic activity tests
        2.1.4 Ribosomal DNA (16S rDNA) sequencing and Y1/Y2 primers DNA amplification
        2.1.5 Identification of the bacterial strains using BIOLOG microbial identification system (BIOLOG)
        2.1.6 Phylogenetic Analysis
    2.2 Results
        2.2.1 Bacteria sample isolation
        2.2.2 16S rDNA Sequencing and Y1/Y2 primers DNA amplification
        2.2.3 BIOLOG microbial identification
        2.2.4 Phylogenetic analysis
        2.2.5 Pathogenicity test results
        2.2.6 Pectolytic test results
    2.3 Discussion
        2.3.1 Phytopathogenic pectolytic bacteria infecting potatoes in Nakuru county, Kenya
        2.3.2 Pectolytic activity of isolated bacteria at different incubation temperatures
CHAPTER THREE: ISOLATION, CHARACTERIZATION AND USE OF BACTERIOPHAGES TO CONTROL PECTOBACTERIUM CAROTOVORUM
    3.1 Materials and Methods
        3.1.1 Phage isolation and purification
        3.1.2 Phage amplification
        3.1.3 Morphology of host bacteria
        3.1.4 Phage morphology assessment by transmission electron microscope
        3.1.5 Lytic activity of phages against Pectobacterium carotovorum
        3.1.6 Bacteriophage one step growth curve
        3.1.7 Antibacterial activity and phage specificity
        3.1.8 Development of phage resistance in Pectobacterium carotovorum
        3.1.9 Bacteriophage efficacy tests in controlling potato soft rot
    3.2 Results
        3.2.1 Phage isolation and purification
        3.2.2 Phhage morphoology
        3.2.3 Lyytic activityy of phagess against Peectobacterium carotov vorum
        3.2.4 Bacteriophage one step growth curve
        3.2.5 Antibacterial activity and phage specificity
        3.2.6 Development of resistance against bacteriophage infection
        3.2.7 Bacteriophage efficacy tests in controlling potato soft rot
    3.3 Disccussion
        3.3.1 Isolated bacteriophages for the control of Pectobacterium carotovorum
        3.3.2 Bacteriophage cocktail to overcome phage-resistance in Pectobacterium carotovorum
CHAPTER FOUR: CONCLUSION AND RECOMMENDATIONS
    4.1 Conclusion
    4.2 Recommendations and future prospects
REFERENCES
LIST OF ABBREVIATIONS AND ACRONYMS
APPENDICES
ACKNOWLEDGEMENTS
RéSUMé and PUBLISHED PAPERS



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