龙羊峡水库土壤真菌多样性及生防菌株筛选

Fungal diversity of soil in Longyangxia valley and screening of biocontrol isolates

摘要:

【背景】 龙羊峡水库是黄河源区重要的湖泊湿地之一，具有巨大的水量调节功能。【目的】 探究龙羊峡水库土壤真菌多样性并筛选生防菌株，丰富高寒湖泊湿地真菌资源，为后续开发生防制剂提供基础材料。【方法】 从龙羊峡水库岸边采集土壤样本10份，采用稀释涂板分离法进行真菌的分离，采用形态学和分子生物学方法鉴定真菌，并使用对峙培养法筛选生防菌株。【结果】 共分离得到104株真菌，经鉴定发现分别属于光黑壳属(Preussia)、木霉属(Trichoderma)、链格孢属(Alternaria)、枝孢霉属(Cladosporium)、平脐蠕孢属(Bipolaris)、假裸囊菌属(Pseudogymnoascus)和青霉属(Penicillium)等23属真菌，其中光黑壳属和木霉属菌株个数最多，分别是21株和19株，分离频率是20.19%和18.27%；枝葡萄孢属(Botryotrichum)、韦斯特壳属(Westerdykella)、小球腔菌属(Leptosphaeria)、节菱孢属(Arthrinium)、齿梗孢属(Scolecobasidium)、孢子丝菌属(Sporothrix)、四枝孢属(Tetracladium)和隐囊菌属(Aphanoascus)菌株个数最少，均为1株，分离频率为0.96%。从104株土壤真菌中筛选得到19株木霉属真菌对青海省主要农作物8种病原真菌具有较强的抑菌效果，抑菌率在51.6%-73.5%之间；10株光黑壳属、4株假裸囊菌属、3株枝孢霉属、2株平脐蠕孢属、各1株节菱孢属、小球腔菌属、韦斯特壳属、青霉属和翅孢壳属(Emericellopsis)真菌通过抗生作用发挥抑菌效果，对8种病原真菌的抑菌带最大宽度均≥10 mm，抑菌效果较好。【结论】 龙羊峡水库土壤真菌资源丰富，具有较好的开发和利用价值。

Abstract:

[Background] Longyangxia valley is one of the most important lake wetlands in the source region of the Yellow River, demonstrating great potential in water regulation. [Objective] To explore the soil fungal diversity and screen biocontrol isolates from Longyangxia valley, enrich the fungal resources of lake wetlands in alpine regions, and provide basic materials for subsequent development of biocontrol agents. [Methods] Ten soil samples were collected from the shoreside of Longyangxia reservoir in Longyangxia valley, and fungi were isolated by the dilution coating method. The isolates were identified by morphological observation and methods of molecular biology, and the biocontrol isolates were screened by the plate confrontation method. [Results] One hundred and four fungal strains belonging to 23 genera were isolated, including Preussia, Trichoderma, Alternaria, Cladosporium, Bipolaris, Pseudogymnoascus, and Penicillium. The isolates belonging to Preussia and Trichoderma were the most, with the number of 21 and 19 and the isolation frequency of 20.19% and 18.27%, respectively. The isolates of Botryotrichum, Westerdykella, Leptosphaeria, Arthrinium, Scolecobasidium, Sporothrix, Tetracladium, and Aphanoascus were the fewest, and all these genera had only one isolate, with the isolation frequency of 0.96%. Nineteen isolates of Trichoderma were screened out from the 104 fungal isolates, and these isolates had great biocontrol effects on eight fungal pathogens isolated from the main crops of Qinghai Province, with the inhibition rates between 51.6%–73.5%. Ten Preussia isolates, 4 Pseudogymnoascus isolates, 3 Cladosporium isolates, 2 Bipolaris isolates, and 1 isolate each of Arthrinium, Leptosphaeria, Westerdykella, Penicillium, and Emericellopsis also exerted strong inhibitory effects on the eight pathogens, with the largest inhibition zone ≥10 mm. [Conclusion] The soil of Longyangxia valley harbors abundant fungal resources and demonstrates high potential of exploitation and utilization.