Construction Of The Stable Microflora In Banana Rhizosphere Soil And Effect Studies

Banana wilt disease, also kown as the Panama disease or yellow leaf disease is a kind of soil-borne disease caused by Fusarium oxysporum.f sp. Cubense FOC infecting the banana plant vascular tissue, leading to a devastating vascular necrosis rotten. It has been considered as a serious threat to banana industry. Biologicalcontrol is one of the most effective methods to control banana Fusarium wilt disease for its safety, green and effectiveness. Biologicalcontrol is mainly based on antagonistic microorganisms for biological control source, after training for plant disease. After a single antagonistic bacteria applied into the soil, it is difficult to compete for the colonization in the soil, and most of the inhibitory action will death, due to can not adapt to the environment. Therefore,researching the antagonistic bacteria fermentation combined with organic fertilizer, the construction of complex microbial flora, analysis of community structure stability, and effects on soil microbial community. It has the important meaning to the banana wilt disease prevention and control and ecological balance.The research mainly study from the separation, identification and liveness of functional bacteria; analysis of stability microflora of construction and community structure; Control effect of microflora fermentation liquid against Banana Fusarium Wilt and promotion effect; As well as the influence of microflora fermentation liquid on soil microbial community, constructing the optimal prevention and control effect of stable microflora on Fusarium Wilt of banana.248strains of bacteria were obtained from the banana rhizosphere soil, Including99strains of antagonistic actinomycetes. Selection of a strain of the functional bacteria M3-4has efficient antagonism on pathogen causing banana wilt. By cultivating character and bacteria morphology observation、physiological and biochemical test-.16SrDNA sequencing, M3-4strain was identified as Streptomyces shaanxiensis.Selecting the test from the banana rhizosphere soil separation to obtain high functional bacterium,M3-4(Streptomyces shaanxiensis), CB-15(Streptomyces spectabilis), JK-2(Bacillus subtilis), and the laboratory has identified and preservated efficient antagonistic bacterium, YB-5(Methylotrophic Bacillus) and RS-01(Bacillus acidi lactici).Respectively intergrowth test in plate and liquid medium, verify its mutual inhibition of growth process, those strains were combined according to their attributes.Using soybean meal and brown sugar as organic matter to allocation fermentation liquid, and Microbial fermentation broth as based flora,With the combination of mixed bacteria fermentation together, build a stable microbial flora in aerobic environment.Dynamic analysis of the microflora community structure and stability use of T-RFLP technology. The results showed that actinomycetes, bacteria and lactic acid of three groups and the fermentation liquid constructed composite microbial flora,it is the highest total amount of microbes. community structure was the steadily, diversity index was the highest,effective TRFs number is the most, relative abundances of the most homogeneous distribution and microbial community diversity is the most abundant with fermentation time increasing.The index is basically stable and the number has tiny change from three day to twenty-one day.The indoor potted experiment is carried out to study the effect of the bacteria fermentation liquid treatment the onset of Banana Seedlings.Results show that8species microflora fermentation liquor can reduce disease index of banana fusarium wilt disease significantly,and the effect on banana wilt disease control is well. Treatment FXRF and FXF had the best effect,banana disease index is11.78and14.77,control effect is82.12%and73.91%.8kinds of microflora fermentation liquor also had significant promoting effect on banana seedlings.Fermentation liquid of functional bacteria combination treatment banana,its the content of chlorophyll,leaf area,root length, root diameter，plant height,stem diameter,fresh weight and dry weight,is better than the fermentation broth of no functional bacteria and CK. FXRF treatment is best, its leaf area is1489.79cm,root length is1393.35cm,root diameter is1.10mm,plant height is47.59cm,stem diameter is7.52cm,fresh weight is57.17g and dry weight is51.13g. All kinds of biomass indicators are higher than the other treatments.Take the banana seedling rhizosphere soil treatment after60d,and analysis of soil microbial community structure about them.Results show that microflora fermentation liquor at the same time in the what increase in soil organic matter and reduce pathogenic bacteria in soil.The colonization of microflora and nutrients stimulate the growth and reproduction of certain antagonistic, increased soil microbial diversity,and inhibition of pathogenic fungal growth and reproduction, improve the structure of soil microbial communities. There was significant difference before treatment and FXRF treatment soil obout microbial flora diversity index. TRFs is7, Shannon-Wiener index is1.49, Evenness index is0.76on pre processing. But FXRF treatment is the best, TRFs is37, Shannon-Wiener index is3.46, Evenness index is0.96.What increased the types and numbers of microorganisms on streptomyces, Flavobacterium, Pseudomonas, B.methylotrophicus and Lactobacillu, that Microbial fermentation liquid treated soil.The purpose of reaching what enrich the soil microbial diversity, improve soil microbial community structure,improve the control effect on Fusarium Wilt of banana and maintain soil micro ecological system.