Screening And Identification Of Biocontrol Bacteria For Cucumber And Tomato Fusarium Wilt

Cucumber(Cucumis sativus L.)and tomato(Solanum lycopersicum)are very important greenhouse vegetables due to their good taste and high nutritional value.They are highly susceptible to fusarium wilt,which seriously reduces the yield and quality of cucumber and tomato.From the perspective of biological control,this study uses the flat panel method to screen out the microbial resources that have biocontrol effects on cucumber and tomato fusarium wilt,laying a foundation for the research on the effective control of fusarium wilt,and further providing for the research and development of biocontrol agents Theoretical basis.(1)Using cucumber and tomato fusarium wilt as pathogens,we screened tomato rhizosphere growth-promoting bacteria,and six of them have inhibitory effects on tomato fusarium wilt.Among them,the three growth-promoting abilities of strain ABY24(IAA production capacity,siderophore production capacity,and phosphorus solubilization capacity)were the best;at the same time,the plate confrontation method was used to screen from cucumber degrading bacteria,and three of them were against cucumber Fusarium wilt has a certain antibacterial activity.The strain I1 90 has the strongest IAA production capacity,the strain II155 has the strongest siderophore production capacity,and the strain I116 has the strongest phosphate solubilizing capacity.Screened from cucumber root stubble degrading fungi,three of them have antagonistic effects on cucumber wilt.Strain III3 37 has the strongest ability to produce IAA,strain I2 13 has the strongest siderophore ability,and strain A1 54 has the strongest phosphate solubilizing ability.(2)According to the identification of morphology,physiology,biochemistry and molecular biology,the six strains of tomato biocontrol strains all have a similarity of more than 99% with Bacillus,while the cucumber degrading bacterial strains II1 55,I1 90,All II1 42 belong to the genus Bacillus.(3)The radicle length and germination rate of tomato treated with strain ABY24 bacterial suspension reached 6.94 cm and 60%,which was the best germination effect among all strains;the disease rate of plants treated with strain ABY24 was the lowest.The tomato root system activity and the activity of tomato defense enzymes added with the strain ABY24 bacterial suspension were higher than those without treatment.In the cucumber plant seedling potted fusarium wilt control experiment,the strain II1 55 had the best effect.In the experiment of the effect of biocontrol bacteria on cucumber root vitality and defensive enzyme activity,the cucumber root vitality and the cucumber defensive enzyme activity added with II1 55 bacterial suspension were higher than those without treatment.In summary,this study has screened out strains ABY24 and II1 55 that have higher bacteriostasis against tomato fusarium wilt and cucumber fusarium wilt and better biocontrol effects at the seedling stage,respectively.The two strains can promote and antagonize growth.The effect is obvious and it has the value of in-depth research.