Isolation,Characterization And Application Of Bacteriophages For Potato Blackleg Biocontrol

Pectobacterium atrosepticum(Pba)caused serious blackleg on stem and soft rot on tuber,by degrading pectins of cell wall in potato plants.Till now,no effective control strategies agaist the blackleg has been reported.Bacteriophage was known that it could lysis microrganisms such bacterum and fungus,and showed potentials on control of plant bacterial diseases.In this study,seven bacteriophages were isolated and identified.The results showed that plaque diameters of seven bacteriophages were between 1.5 mm and 2 nm.A wide range of MOI were found between 0.000001 and 0.01.Three key factors,including adsorption time,laterncy time and lysis time,were monitored.A significant differentiation has been observed in all three factors.The adsorption time was between 6 min and 30 min.The latency time was between 15 min and 40 min.The lysis time was between 40 min and 80 min.Three bacteriophages,P-Pba-1,P-Pba-2 and P-Pba-7,were selected for morphyogy identification and field application.Tails were not observed in all three bacteriophages,and the diameter of the head was between 30 nm and 80 nm.Select G1 and G2 for blackleg treatment and prevention the in the field.In the G1 treatment,the survival rate of the potato plants was 40%-100%.G1-A4 showed the hightest vigor with survival rate of 100%.In the G2 treatment,the survival rate of the plants was 60%-90%.G2-A3 showed the highest vigor with survival rate of 90%.In the G1 prevention group,the survival rate of the plants was 60%-100%.The survival rate of G1-B1 and G1-B2 reached up to 100%.In the G2 prevention group,the survival rate of plants was 80%-100%,and G2-B1 and G2-B2 showed the best control effects with survival rate of 100%.This results indicated that bacteriophages could be applicable and effective for biocontrol of potato blackleg.Bacteriophages will be a promising strategy for bacterim diseases control of plants in future.