| Strawberry is easily infected by pathogenic microorganism in the process of planting,and the phenomenon of dead seedlings and roots is frequent,which brings serious economic losses to berry farmers.Therefore,the identification of the types and characteristics of pathogenic microorganism of strawberry root diseases,and screening of antagonistic antibacterial is very important which can lay a theoretical foundation for the biological control of strawberry root diseases.In this thesis,the pathogenic microorganism were isolated from the strawberry roots,and identified by mean of growth traits,and molecular biology.As the target pathogen,the antagonistic bacteria were screened and identified through the plate confrontation test and molecularly method,and then the potted test methods were applied to further verify their biocontrol effects.The main findings are as follows:1)In this experiment,samples of strawberry root rot disease were collected from strawberry planting bases in Beijing,and 7 strains were obtained by tissue isolation method,including: FSt R-YF-01,FSt R-YC-02,FSt R-YF-03,FSt R-YF-04,FSt R-YC-05,FSt R-YC-06,and FSt R-YF-07,after purification,culture,back-joining verification,through morphological identification,combined with molecular biological identification,it is clear that the pathogenic bacteria of strawberry root rot are Fusarium oxysporum: FSt R-YF-01,FSt R-YF-03,FSt R-YF-04,FSt R-YF-07 and Colletotrichum siamense: FSt R-YC-02,FSt R-YC-05,FSt R-YC-06.2)66 strains of bacteria were isolated from strawberry rhizosphere soil,greenhouse soil,compost and other samples,and 31 strains with antagonistic effects were selected from them.Fusarium oxysporum and Colletotrichum siamense were used as target pathogens.The 31 strains of bacteria obtained were screened and re-screened by the plate confrontation method,and 4 strains of Bacillus with better biocontrol effects(Fu-FB-04,Fu-FB-11,Fu-FB-14 and Fu-FB-24),the antagonistic effect is above 72%.According to 16 S r DNA identification,Fu-FB-04 and Fu-FB-14 belong to Bacillus velezensis;Fu-FB-11 and Fu-FB-24 belong to Bacillus subtilis;the four strains have good antagonistic effects on Fusarium oxysporum and Colletotrichum siamense.3)After antagonistic strain compatibility determination and pot experiment,the results show that the biocontrol effect of a single biocontrol bacteria is better than that of no biocontrol bacteria,and the compound biocontrol bacteria is better than a single strain. |
