培养条件对三株燕麦内脐蠕孢菌生长及产孢的影响

Culture conditions influence the growth and sporulation of three strains of Drechslera avenacea

摘要:

背景 燕麦内脐蠕孢菌(Drechslera avenacea)是燕麦叶斑病的主要病原物，该菌产孢量不足严重影响了对燕麦与其互作的研究进度。目的 筛选出燕麦内脐蠕孢菌生长和产孢的最适培养基和培养条件，为该菌引起的燕麦叶斑病的相关研究及防治提供基础。方法 对内脐蠕孢菌的最适培养基、碳源、氮源及其在V8培养基上不同温度、pH、紫外照射时间下的产孢量进行了研究。结果 3株菌在不同培养基、碳氮源、温度、pH值、紫外线照射时间等条件下的菌落生长、产孢量呈现分化现象。经过12 d培养，菌株hsbzb和菌株plpjg以麦芽糖为碳源，菌落直径均在69 mm以上；以蛋白胨为氮源，菌落直径均在77 mm以上；菌株dttz以麦芽糖为最适碳源，菌落直径达38.22 mm，以蛋白胨为氮源，菌落直径为38.52 mm。3株菌在V8培养基上生长4周后，产孢量和菌落直径在温度上表现具一致性，其最适温度为25 ℃；偏酸条件(pH 4.5)有利于其产孢，反之则不利于其生长；紫外照射能够在短时间内使内脐蠕孢菌产孢，照射时间以8 h为最佳，并且可诱导不产孢的内脐蠕孢菌菌株dttz产孢。结论 本研究明确了燕麦内脐蠕孢菌的最适生长与产孢条件，为高效获取病原菌孢子、深化宿主-病原菌互作研究及燕麦叶斑病综合防治策略制定提供了关键技术支撑。

Abstract:

Background Drechslera avenacea is the main pathogen of oat leaf spot, while the insufficient sporulation of this fungus has seriously affected the research progress in the interactions between oat and D. avenacea.Objective To screen the most suitable medium and culture conditions for the growth and sporulation of D. avenacea, and to provide a basis for the research and control of oat leaf spot caused by D. avenacea.Methods We determined the optimal medium, carbon source, and nitrogen source of D. avenacea, as well as the sporulation in the V8 medium under different temperatures, pH values, and ultraviolet (UV) irradiation time.Results The mycelial growth and sporulation of the three strains were different under different media, carbon and nitrogen sources, temperatures, pH values, and UV irradiation time. After 12 days of culture, the colony diameters of strains hsbzb and plpjg were more than 69 mm in the media with maltose as the carbon source and more than 77 mm in the media with peptone as the nitrogen source. Strain dttz had the largest colony diameter of 38.22 mm when maltose was used as the carbon source and 38.52 mm when peptone was used as the nitrogen source. After 4 weeks of growth in the V8 medium, the sporulation and colony diameters of the three strains showed consistent trends with the rise in temperature, and the optimal temperature was 25 ℃. An acidic environment (pH 4.5) was conducive to sporulation. UV irradiation promoted the sporulation of D. avenacea in a short period of time, and the optimal irradiation time was 8 h. Moreover, UV radiation induced the sporulation of strain dttz which did not produce spores.Conclusion This study clarified the optimal growth and spore production conditions of D. avenacea, providing key technical support for the efficient acquisition of pathogen spores, in-depth research on host-pathogen interactions, and the formulation of comprehensive prevention and control strategies for oat leaf spot disease.