米修链霉菌TF78对香蕉枯萎病的田间防效及根际土壤微生物的影响

【背景】香蕉枯萎病是香蕉生产上的毁灭性病害，生物防治是遏制该病害发生的有效手段。在前期的研究中，从健康香蕉根际土壤中分离获得一株对香蕉枯萎病具有良好盆栽防治效果的生防菌——米修链霉菌(Streptomyces misionensis) TF78，但其对香蕉枯萎病的田间生防潜力和对土壤微生物环境的影响尚不清楚。【目的】评价米修链霉菌TF78对香蕉枯萎病的田间防治效果，明确其对香蕉根际土壤微生物群落的影响。【方法】选取两块发病香蕉园，测定该生防菌株对香蕉枯萎病的防治效果，并利用扩增子测序技术分析施用菌剂组和空白对照组共12份香蕉根际土壤的微生物多样性和丰度。【结果】米修链霉菌TF78对两块香蕉园的田间防效分别达55.30%和45.32%。该生防菌株处理组的物种稀释曲线坡度大于空白对照组，并显著富集了优势种群梳霉门(Kickxellomycota)，消减了绿弯菌门(Chloroflexi)、酸杆菌门(Acidobacteria)和苔藓杆菌(Bryobacter)的丰度，对土壤中优势种群变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、放线菌门(Actinobacteria)、芽单胞菌门(Gemmatimonadetes)及木霉属(Trichoderma)、鞘氨醇单胞菌属(Sphingomonas)、寡养单胞菌属(Stenotrophomonas)和芽孢杆菌属(Bacillus)的相对丰度影响不显著。【结论】米修链霉菌TF78塑造了不利于香蕉枯萎病菌Fusarium oxysporum f.sp.cubense存活的土壤环境，有效降低了田间香蕉枯萎病的发生，同时对土壤中大部分具有重要生态功能和抑菌功能的优势微生物种群影响不显著。该研究结果为米修链霉菌TF78的进一步开发应用奠定了基础。

Effects of Streptomyces misionensis TF78 on fusarium wilt of field-grown banana and rhizosphere soil microorganisms

Background] Fusarium wilt of banana is a devastating disease in banana production. Biological control is an effective means to prevent the occurrence of this disease. In previous studies, Streptomyces misionensis TF78, a biocontrol strain, was isolated from the rhizosphere soil of healthy bananas, which showed good control effect on fusarium wilt of potted bananas. However, the biocontrol potential of S. misionensis TF78 against fusarium wilt of banana in the field and its impact on soil microbial environment are still unclear.Objective] The paper was designed to evaluate the control effect of S. misionensis TF78 on fusarium wilt of banana in the field and determine its influence on the microbial communities in the rhizosphere soil of bananas. Methods] The control effect of the biocontrol strain on fusarium wilt of banana was measured in two banana plantations. Microbial diversity and abundance of 12 rhizosphere soil samples from the inoculation group and the blank control group were analyzed by amplicon sequencing. Results] The field control efficiency of S. misionensis TF78 on the two banana plantations were 55.30% and 45.32%. The slope for rarefaction curve of the inoculation group was larger than that of the blank control group, and Kickxellomycota was significantly enriched, while the abundances of Chloroflexi, Acidobacteria and Bryobacter were reduced. The biocontrol strain had no marked effect on the relative abundances of the dominant Proteobacteria, Firmicutes, Actinobacteria, Gemmatimonadetes, Trichoderma, Sphingomonas, Stenotrophomonas and Bacillus in the soil. Conclusion] S. misionensis TF78 shaped the unfavorable soil environment to the survival of Fusarium oxysporum f. sp. cubense, and reduced the occurrence of fusarium wilt of banana in the field. Additionally, the strain failed to affect most of the dominant microbial populations with important ecological and bacteriostatic functions in the soil. The results lay a foundation for further development and application of S. misionensis TF78.