八角枫内生放线菌的分离及发酵产物杀松材线虫活性研究

Filtering of Endophytic Actinomycetes and Fermentation Products of Alangium chinense for Their Nematicidal Activity Against Bursaphelenehus xylophilus

筛选对松材线虫具有毒杀作用的生防放线菌。通过组织分离法从八角枫茎、叶、枝组织中共分离得到17株内生放线菌,经摇瓶培养、乙酸乙酯萃取制备胞外、胞内次生代谢产物,采用浸渍法开展内生放线菌代谢产物对松材线虫的室内毒力实验。从中筛选出2株内生放线菌(G-5和G-17)的胞外代谢产物杀线虫活性显著,G-5和G-17胞外发酵产物经24 h处理后LC_(50)值分别为0.9527和0.4196mg·mL^(-1)。通过形态学观察和分子生物学手段16SrDNA的序列分析对两株活性菌株进行鉴定,经鉴定二者均属链霉菌属(Streptomyces)。结果表明:八角枫内生放线菌G-5、G-17胞外发酵产物对松材线虫具有较高的毒杀活性,在松材线虫病的生物防治中具有潜在的应用价值。

Screening of biotic actinomycetes has virulent effect on pine nematodes.A total of 17 strains of endophytic actinomycetes are isolated from the stem,leaf and branch tissues of Alangiumchinense(Lour.)Harms by tissue isolation,and the extracellular and intracellular secondary metabolites were prepared by shaking flask culture and ethyl acetate extraction.The nematicidal activity of the extracellular metabolites of two endophytic actinomycete strains(G-5 and G-17)was significant,and the LC_(50) values of the extracellular fermentation products of G-5 and G-17 were 0.9527 mg·mL^(-1) and 0.4196 mg·mL^(-1) after 24h treatment,respectively.The two active strains were identified as Streptomyces.The results showed that the extracellular fermentation products of endophytic actinomycetes G-5 and G-17 from Streptomyces sp.were highly toxic and had potential applications in the biological control of pine wood nematodes.