| Banana soil borne wilt is prevalent in banana producing areas in China.Nature magazine reported in 2013 that the disease has seriously threatened the development of global banana industry,and it is urgent to take effective measures to slow down the spread of banana soil borne wilt.Trichoderma,as a competitive antagonistic microorganism,is widely used in many crop soil borne diseases.In this paper,through the combination of indoor mycelium growth,spore production determination,plate confrontation,button culture,pot experiment,real-time fluorescent quantitative PCR and high-throughput sequencing technology,Fusarium oxysporum No.4 physiological race(Fusarium oxysporum f.sp.Cubense race 4,FOC4)as a pathogen,with T.asperellum(GX004)as an antagonistic strain,to study its biological characteristics and optimization of solid fermentation conditions,and two Tri-fermentation bio-fertilizer was developed by sub-fermentation,and its effects on soil microorganisms of different resistant banana varieties were discussed.The results obtained are as follows:1.Biological characteristics of Trichoderma and development of bio-fertilizerUnder the influence of culture temperature,pH and light,T.asperellum(GX004)can produce the largest amount of spores under the condition of culture temperature of 28,pH=5～6 and full light.In the plate,T.asperellum(GX004)can significantly inhibit the growth of pathogenic bacteria,with the inhibition rate of 85.2%;the inhibition rate of volatile substances on the growth of pathogenic bacteria is 39.5%;the inhibition rate of T.asperellum(GX004)spore culture medium with different spore concentration on pathogenic bacteria is 39.5%Different,when the concentration of Trichoderma spore solution was 1.65×10~6/ml,FOC4 could hardly grow.Under laboratory conditions,rice straw and rapeseed cake were used as solid fermentation substrate to explore the effect of single factor and different conditions on their sporulation.The results showed that the ratio of rice straw and rapeseed cake was 1:1 by mass,sterilized at 121℃ for 30 minutes,inoculated at 8%～12%,and the initial water content was adjusted to The spore yield can reach more than 2.0×10~9/g in a constant temperature incubator at 28℃for 5 days.The ratio of fermentation products to manure organic fertilizer was 1∶9,which was higher than the national standard of bio organic fertilizer.The content of Trichoderma spores was≥1.50×10~8/g,the total nitrogen,phosphorus,potassium nutrients was≥5%,and the organic matter content was≥45%.2.Colonization of Trichoderma in banana soil and its control effect on Banana Fusarium WiltApplying Trichoderma bio-fertilizer can significantly increase the copy number of Trichoderma in banana soil and rhizosphere soil(P<0.05),while Trichoderma bio-fertilizer can not significantly reduce the copy number of Fusarium oxysporum in banana rhizosphere and rhizosphere soil(P>0.05).Trichoderma can be planted in the rhizosphere of three varieties of banana.The colonization of Trichoderma in the rhizosphere of resistant varieties of South Tianhuang is significantly higher than that of Brazil banana and Baodao banana(P<0.05).The incidence rate of incidence of Fusarium Wilt of banana and Nantianhuang banana decreased significantly compared with that without bio organic fertilizer,They were reduced by 13.3%～20% and 13.4% respectively,The incidence rate of the different varieties of bio-fertilizer was significantly different,and the incidence rate of Southern Tianhuang was the lowest.3.Effect of Trichoderma bio-fertilizer on soil microbial community structure of different resistant banana varietiesThrough pot experiment,it was found that the soil community structure of different disease resistant banana varieties was different under the same fertilization treatment,while the application of Trichoderma bio organic fertilizer changed the soil community structure of different disease resistant banana varieties,and had different effects on the soil and rhizosphere soil microbial community structure of different disease resistant banana varieties.In the soil,the application of Trichoderma bio-fertilizer significantly reduced the diversity of banana and Nantianhuang fungus in Baodao(P<0.05),but had no significant impact on the bacterial richness and diversity of different resistant varieties(P>0.05).From the community structure,the Trichoderma bio-fertilizer changed the community structure of bacteria and fungi of different resistant varieties in the soil,but on the south There was no significant effect on the community structure of rhubarb.In rhizosphere soil,compared with the treatment without fertilization and cow dung organic fertilizer,the treatment with Trichoderma bio-organic fertilizer significantly increased the community richness of Brazil banana bacteria(P<0.05),and decreased the community diversity of the Nantianhuang.From the perspective of community structure,Trichoderma bio-organic fertilizer all changed the community structure of different resistant varieties of bacteria and fungi in the soil,but had no significant effect on the community structure of the fungus in Baodao.4.Effect of Trichoderma bio-organic fertilizer on soil microbial community composition of different resistant banana varietiesThrough pot experiments,it was found that Trichoderma bio-organic fertilizer has different effects on the community structure composition of soil microorganisms and rhizosphere soils of different resistant banana varieties:In the soil,compared with no fertilization and cattle manure organic fertilizer treatment,Trichoderma bio-fertilizer treatment increased the relative abundance of Acinobacteria and Basidiomycota,increased the relative abundance of Acinobacteria and Ascomycota in Baodao,and decreased the relative abundance of Proteobacteria and basi Diomycota increased the relative abundance of Proteobacteria.In rhizosphere soil,the treatment of Trichoderma bio-fertilizer and cattle manure organic fertilizer increased the relative abundance of Proteobacteria and Ascomycota,but compared with the treatment of no fertilizer and cattle manure organic fertilizer,the treatment of Trichoderma bio-fertilizer decreased the relative abundance of Brazilian banana and Basidiomycota,and increased the relative abundance of Basidiomycota The relative abundance of Basidiomycota was increased,the relative abundance of Ascomycota was increased,and the relative abundance of Ascomycota was decreased.At the same time,the relative abundances of Fusarium and Trichoderma were negatively correlated in the soil and rhizosphere soil,and there was only interaction between banana varieties and Fertilization on the rhizosphere soil.Compared with the treatments of no fertilization and cow manure,Trichoderma bio-fertilizer significantly increased the relative abundance of soil and rhizosphere,and decreased the relative abundance of Fusarium. |
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