黄柄曲霉ASD对辣椒疫病根际真菌菌群结构及土壤功能的影响

为阐明辣椒疫病生防菌黄柄曲霉ASD的土壤微生态调控机理，本研究利用化学方法与Illumina HiSeq平台分析了ASD菌液对罹病辣椒根际土壤特性及真菌多样性的影响。结果表明，ASD菌液的施入可以明显提高罹病土壤硝态氮与有效钾含量，降低铵态氮含量与N-乙酰基-β-D-氨基葡糖苷酶活性。ASD菌液增加了罹病辣椒根际土壤真菌多样性与丰度，从而改变了辣椒根际优势真菌群落构成。优势种群与发病率相关分析结果表明，丰度上升的嗜热链球菌属与嗜热毁丝霉属等9个物种与发病率呈负相关，丰度降低的斜盖伞属及近地伞属与发病率呈正相关。与环境因子相关性分析表明，有效钾、硝态氮的含量与ASD处理的土壤真菌多样性呈正相关，并正向影响锥盖伞属等10个物种，铵态氮含量及N-乙酰基-β-D-氨基葡糖苷酶活性则反之。综上所述，黄柄曲霉ASD可以增加辣椒疫病根际土壤真菌多样性，改变土壤营养状况与优势真菌种群结构，从而降低辣椒疫病的发病率。结果可为菌株ASD应用于生产实践提供理论基础。

Effects of Aspergillus flavipes ASD on the Structure of Rhizosphere Fungi and Function of Soil infected by Phytophthora capsici in Pepper

To explain the soil microbial regulation mechanism of biocontrol strain Aspergillus flavipes ASD against pepper blight, the effects of rhizosphere soil characteristics and fungal diversity of affected pepper were analyzed by chemical methods and Illumina HiSeq platform after application of ASD strain solution. The results showed that the application of ASD strain solution could significantly increase the contents of nitrate nitrogen and available potassium in the affected soil, while decreased the content of ammonium nitrogen and the activity of N-acetyl-β-D-aminoglycosidase. The application of ASD bacterial fluid increased the diversity and abundance of fungi in the rhizosphere soil of the affected pepper, which resulted in the variation of dominant fungal community. Correlation analysis of dominant fungi and disease incidence showed that 9 genuses such as Mycothermus and Myceliophthora with an increasing abundance were negatively correlated with the disease incidence, whereas Clitopilus and Parasola with a decreasing abundance were positively correlated with the incidence. Correlation analysis with environmental factors showed that the contents of available potassium and nitrate nitrogen were significantly positively correlated with fungal diversity after ASD treatment, and positively affected 10 genuses such as Conocybe. However, the content of ammonium nitrogen and the activity of N-acetyl-β-D-aminoglycosidase activity were opposite correlation. In summary, Aspergillus flavipes ASD could increase the rhizosphere soil fungal diversity of pepper blight, change the soil nutritional status and dominant fungal community structure, thereby reduce the incidence of pepper blight. These results could provide the theoretical basis for the application of ASD strain in production practice.