【摘要】 【目的】禾谷镰刀菌是引起小麦赤霉病、玉米茎腐病等一系列土传病害的病原菌，严重威胁了食品安全和人畜健康。利用微生物互作关系抵御病原菌侵染并减少土壤中病原菌的丰度是土传病害防控的新思路。其中，假单胞菌在抑制病原菌生长和增殖中具有较大潜力。然而，接种外源菌种对土壤微生物群落的影响及其潜在的级联效应尚不清晰。本文目的是揭示接种假单胞菌后土壤禾谷镰刀菌丰度变化以及对土著微生物群落的影响，并确定合理的假单胞菌接种量。【方法】本研究通过接种不同浓度的产氮假单胞菌(Pseudomonas azotoformans,PA)和蒙氏假单胞菌(Pseudomonas mandelii,PM)，开展了为期28 d的室内培育实验。利用qPCR和扩增子测序技术，定期监测土壤中禾谷镰刀菌丰度和土著微生物群落变化，进而评估特定假单胞菌在生产中的应用潜力。【结果】结果表明接种低浓度的PM对各时期（7 d和28 d）病原菌的抑制效果更好，分别达22.73%和43.56%。土壤微生物群落组成和物种差异丰度分析表明，在病原菌侵染条件下，接种假单胞菌均增加了7 d时假交替单胞菌、微球菌、间孢囊菌等相对丰度，减少了鞘脂单胞菌、绿弯菌、放线菌等相对丰度。同时也增加了28 d时根瘤菌、假交替单胞菌和蛭弧菌等相对丰度，减少了枝孢菌和芽孢杆菌的相对丰度。所富集的假交替单胞菌、微球菌、根瘤菌等主要通过促进土壤有机质周转、土壤固氮以及产生抗生素等物质，提升土壤和植物健康；而减少的酸杆菌和子囊菌等物种，在一定程度上体现了接种假单胞菌后土壤微生物的富营养性。【结论】与添加高浓度的PM处理相比，接种低浓度PM物种对禾谷镰刀菌的抑制效果更好。本研究为禾谷镰刀菌的绿色防控、假单胞菌的田间应用以及农业可持续发展提供了理论依据。更多还原

【Abstract】 [Objective] Fusarium graminearum, is a pathogenic fungus that can cause a series of soil-borne diseases such as Fusarium Head Blight and Maize stalk rot, which seriously threatens food safety and human health. Taking advantage of microbial interactions to resist pathogenic fungus infection and reduce the abundance of pathogenic fungus in the soil is a new strategy for the prevention and control of soil-borne diseases. Among them, Pseudomonas has the great potential in inhibiting the growth and proliferation of pathogenic fungus. However, the impact of inoculating exogenous strains for soil microbial communities and its potential of cascading effects are unclear. The aims were to reveal the inhibitory effect of inoculating Pseudomonas on Fusarium graminearum in soil and its impact on indigenous microbial communities, and to ensure the optimal inoculation amount. [Method] This study carried out indoor incubation experiment by inoculating different concentrations of Pseudomonas azotoformans(PA) and Pseudomonas mandelii(PM) up to 28 days.Using qPCR and amplified sequencing technology, regularly monitor the abundance of Fusarium graminearum in soil and the changes of indigenous microbial communities, and then to evaluate the potential application of specific Pseudomonas species in agricultural production. [Result] The results showed that inoculating low concentrations of PM had better inhibitory effects on Fusarium graminearum in different sampling times(on the 7th d and 28t~h d), what inhibitory effects have been reached 22.73% and 43.56%. The analysis of soil microbial community composition and differential abundance of species showed that the inoculation of Pseudomonas could increase the relative abundances of Pseudoomonadaceae, Micrococcaceae and Intrasporangiaceae on the 7th day under the condition of pathogen infection. While the relative abundance of specific species could ben reduced, for example Sphingomonadaceae,Chloroflexaceae and Gaiellaceae. And on the 28th day, the number of Rhizobiacea, Pseudoomonadaceae and Bdellovibrionaceae so on hadveincreased, while the relative abundances for Cladosporiaceae and Bacillaceae have been reduced. The enriched the specific species,such as Pseudoomonadaceae, Micrococcaceae and Rhizobiacea could promote soil organic matter turnover, improve the agricultural soil carbon sequestration and produce antibacterial substances to improve soil and plant health. The relative abundances of Acidobacteriota and Ascomycota were decreased, reflecting the eutrophication of soil microorganism after Pseudomonas had been inoculated. Therefore,inoculating low-concentration PM was the optimal concentration and species for reducing the abundance of Fusarium graminearum in soil. [Conclusion] This study provides a green way the prevention and control of Fusarium graminearum, which offers a theoretical basis for field application of Pseudomonas spp., and the sustainable development of agriculture.更多还原