土壤生防菌的筛选及其对小麦赤霉病的防控效果

Screening of soil biocontrol bacteria and evaluation of their control effects on Fusarium head blight of wheat

摘要:

小麦赤霉病(Fusarium head blight, FHB)是由禾谷镰刀菌(Fusarium graminearum)引起的重要病害，不仅造成了严重产量损失，其产生的真菌毒素更威胁了粮食安全。该病害具有“可防不可治”的特点，目前主要依赖化学防治，但长期使用化学药剂易导致病原菌抗药性和环境污染。为开发绿色防控方法，本研究从小麦根际土壤中筛选获得13种生防菌，其中第12号菌株[鉴定为瓜果腐霉(Pythium aphanidermatum)]表现出显著抑菌效果。结果显示，该菌株在平板对峙实验中，使病原菌菌落直径减少69.2% (1.47 mm vs. 对照组4.78 mm)，抑制率达77% (P < 0.01)。显微观察发现病原菌菌丝出现明显畸变，表明存在溶菌作用。胚芽鞘实验进一步证实，菌株预处理可使发病率降至0。本研究为小麦赤霉病的生物防治提供了新的候选菌株，并为减少化学农药使用、促进农业可持续发展提供了科学依据。

Abstract:

Fusarium head blight (FHB), caused by Fusarium graminearum, not only leads to severe yield losses but also poses a threat to food safety due to the mycotoxins produced by the pathogen. Since this disease is preventable but not curable, the current control mainly relies on chemical fungicides, the long-term use of which may lead to pathogen resistance and environmental pollution. To develop green control methods, we screened 13 biocontrol strains from the rhizosphere soil of wheat, among which strain No. 12 (identified as Pythium aphanidermatum) showed significant antifungal effects. In the plate confrontation test, this strain reduced the colony diameter of the pathogen by 69.2% (1.47 mm vs. 4.78 mm in the control group), with an inhibition rate of 77% (P < 0.01). Microscopic observation revealed obvious deformations in the pathogen hyphae, suggesting a lysing effect. The coleoptile experiment further confirmed that the pre-treatment with this strain reduced the incidence rate to 0. These findings provide new candidate strains for the biocontrol of FHB and offer a scientific basis for reducing the use of chemical fungicides and promoting sustainable agricultural development.