八角枫内生真菌的分离鉴定及其发酵产物对松材线虫的毒杀活性

旨在筛选对松材线虫具有毒杀作用的生防真菌。通过组织分离法从八角枫茎、叶组织中共分离得到11株内生真菌，经摇瓶培养、乙酸乙酯萃取制备次生代谢产物，采用浸渍法开展内生真菌代谢产物对松材线虫的室内毒力试验，结合形态特征和ITS序列分析对活性菌株进行鉴定。结果表明，一株内生真菌（BZ-8）发酵液杀线虫活性显著，通过形态学与分子生物学均鉴定为Aspergillus japonicus，其发酵液有机相24 h和48 h的IC₅₀值分别为0.29 mg·mL^-1和0.21 mg·mL^-1，水相24 h和48 h的IC₅₀值分别为0.04 mg·mL^-1、0.02 mg·mL^-1。研究结果说明，八角枫内生真菌A.japonicus的胞外次生代谢产物对松材线虫具有显著的毒杀效果，值得进一步研究。

Isolation and Identification of Endophytic Fungi from Alangium chinense and Nematicidal Activity of Fermentation Products against Pine Wood Nematode,Bursaphelenehus xylophilus

To indentify theendophytic fungi with nematicidal activity against Bursaphelenehus xylophilus nematicidal,elevenendophytic fungi strainswere isolated from stems and leaves of Alangium chinense,and extracellular secondary metabolites were obtained through shake flask culture and ethyl acetate extraction. The indoor nemataicidal toxicity of secondary metabolites from endophytic fungi against pine wood nematode was assayed using immersion bioassay. The active strains were identified based on morphological and ITS. Among theextracellular metabolites,endophytic fungi (BZ-8) exhibited significant nematicidal activity,and was identified as Aspergillus japonicusby morphology and molecular biology. The IC₅₀ values of the organic and aqueous phases of the culture broth from A.japonicus at 24 h and 48 h were determined,with the aqueous phase showing the most potent nematicidal activity (IC₅₀ values of 0.04 mg·mL^-1 and 0.02 mg·mL^-1 at 24 h and 48 h,respectively).The results showed that extracellular fermentation products from A.japonicus have significant nematicidal activity against pine wilt nematode.