目的 从防风根际土中分离筛选出对防风枯萎病具有较强防治效果的生防真菌。方法 采用对峙培养法从根际土壤中筛选出1株可拮抗尖孢镰刀菌的真菌菌株MR-97，并测定其抑菌谱；根据真菌菌落特征、显微特征，结合ITS序列分析等方法对拮抗菌株进行鉴定；通过显微观察MR-97对尖孢镰刀菌菌丝生长的影响；采用抗生素标记法测定拮抗菌株在土壤中的定殖能力；进行田间盆栽试验，检验MR-97对防风枯萎病的防治效果。结果 本研究筛选出1株对尖孢镰刀菌抑菌效果为64.44%的拮抗菌株MR-97，其对木贼镰刀菌、灰葡萄孢等8种常见病原菌具有较强的抑菌效果，经鉴定菌株MR-97为土曲霉Aspergillus terreus。MR-97与尖孢镰刀菌对峙培养可使病原菌菌丝产生膨大、畸形、菌丝破损、内含物凝集等现象；在土壤中具有良好的定殖效果，土壤含菌量最高为9.8×106 CFU/g。盆栽试验中，MR-97对防风枯萎病防效为67.86%，防治效果较好。结论 土曲霉MR-97可有效抑制尖孢镰刀菌等多种病原菌菌丝生长，可在土壤中较快定殖并发挥生防效力。作为优质的生防菌源，MR-97具有一定的开发应用潜力。
Objective The present study aimed to screen and isolate the antagonistic fungal strains with strong control effect against fusarium wilt from rhizosphere soil of Saposhnikovia divaricata.Method The strain MR-97, which was antagonistic to Fusarium oxysporum, was isolated from the rhizosphere soil of S. divaricata by confrontation culture method, and its bacteriostatic spectrum was determined. The strain was identified by fungal colony characteristics, microscopic characteristics and ITS sequence analysis. The effect of strain MR-97 on hyphae growth of pathogenic fungus were recorded by microscopic examination. The colonization ability of strain MR-97 in the soil was evaluated by antibiotic marker method. The control effect of strain MR-97 on fusarium wilt of S. divaricata were evaluated by pot experiment in the field. Result The antagonistic strain MR-97 was screened with antibacterial rate of 64.44% against F. oxysporum. It also had strong antibacterial effect against eight common pathogens including F. equiseti and Botrytis cinerea, etc. The strain MR-97 was identified as Aspergillus terreus. The hyphal of pathogen enlargement, malformation, damage and agglutinated with inclusions, etc. when the strain MR-97 and F. oxysporum were cultured in confrontation. It had a good colonization effect in the soil, and the highest content of soil bacteria was 9.8×106 CFU/g. The biocontrol effect of MR-97 on fusarium wilt of S. divaricata was 67.86% in pot experiment, which had good control efficiency. Conclusion Aspergillus terrestris MR-97 can effectively inhibit the mycelia growth of F. oxysporum and other pathogens, can colonize quickly in soil and has strong biocontrol effect. MR-97 strain, as a good source of biocontrol bacteria, has certain potentials of development and utilization.