| Banana is an important tropical fruit in the world.However,the banana industry has been severely tested by the destruction of banana blight.The screening of excellent antagonistic microorganisms and the application of bio-bacterial fertilizers have become the main technical means for biological control of banana fusarium wilt..In this study,11 strains of antagonistic bacteria with excellent Inhibitory ability were screened from the soil of Zhangzhou.Antagonistic fermentation broth was formulated and the pot culture was used to verify the disease resistance.The antagonistic bacteria with better disease resistance were screened to compound bio-bacteria fertilizers.The pot culture was applied to explore the effects of bio-bacteria fertilizers on banana growth,rhizosphere soil,and soil rhizosphere microbial communities.The results showed:1)A total of 37 strains with antibacterial ability were initially screened and 11 strains of antagonistic strains against banana fusarium wilt pathogens were screened again,and the inhibitory rate was higher than 50%.The antagonistic bacteria HQB8022 had the highest inhibition rate of 69.1%,and the antagonistic fungus HQF8021 had the highest inhibition rate of 61.1%.The pot experiment was used to test the disease resistance of the antagonistic broth.It was found that fermentation broth of antagonistic strains HQB 8021,HQB 8022,and HQF 8021 perform better control effects when applied lonely,and the disease index was 10,15,and 45,respectively.Among them,fermentation broth of HQB8021 has the best control effect,banana seedlings have the lowest disease index and the growth of banana seedlings was promoted significantly.2)The bio-bacterial fertilizer had a well anti-blight effect prepared with antagonistic strains HQB8021 and HQF8021.Using fermented chicken manure,rapeseed cake and tapioca slag as raw materials for organic fertilizers,exploring the fermentation effects of antagonistic strains HQB 8021 and HQF 8021 in mixed carriers of different mass ratios.The results showed that when the mass ratio of chicken manure,rapeseed cake and cassava slag was 55:20:30,it was most suitable for the growth of antagonistic strains HQB8021 and HQF8021.Pot culture showed that the application of bio-bacteria fertilizer can reduce the incidence of banana fusarium wilt significantly,the lowest incidence rate reached 28%.3)The bio-bacterial fertilizer based on the HQB8021 strain improved the rhizosphere environment of banana seedlings significantly.The application of bio-bacterial fertilizer increased the content of available nitrogen,available phosphorus,available potassium and organic matter in the rhizosphere significantly,reaching 120.40 mg/Kg,120.11 mg/Kg,64.72 mg/Kg and 10.03 g/Kg,respectively.Compared with the control group of without bio-bacterial fertilizer,increaseing 385%,205%,507%,and 449% respectively.The application of bio-bacteria fertilizer increased the activity of plant antioxidant enzymes significantly.Compared with the control group of without bio-bacteria fertilizer,the activities of CAT,POD and SOD in banana seedlings was increased significantly,reaching 26.51 U/g.FW/min?4421.62 ug/g.FW/min?686.25 U/g.FW.The 16 S r DNA high-throughput sequencing of bacterial communities in the rhizosphere of banana seedlings revealed that the application of bio-bacterial fertilizer can increase the richness of bacterial species in the rhizosphere soil,It can also inhibit the growth of Phylum Firmicute,and the proportion of Bacteroidetes was increased at the same time.The abundance of Truepera,Sphingobacterium,Gelidibacter,Luteimonas,etc.was promoted,but abundances such as Lactobacillus,Bifidobacillus,Shewanella,Sphingomonas,and Ralstonia were reduced significantly.The bio-bacteria fertilizer improved the bacterial community structure in the rhizosphere soil obviously,furthermore,promoted the growth of beneficial microbial flora and increased the abundance of beneficial microbial flora at the same time. |
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