南方根结线虫拮抗放线菌的分离、鉴定与杀线虫活性分析

摘要

采用稀释分离法从连作大豆根际土壤中分离到1株放线菌H-2，对其进行了形态学特征、培养特征、生理生化特征鉴定及16S rDNA分析，初步鉴定H-2菌株为小链霉菌（Streptomyces parvus）。离体生物测定了小链霉菌H-2菌株发酵培养滤液对南方根结线虫和小杆线虫的生物活性。结果表明：H-2菌具有较高的选择性杀线虫活性，对南方根结线虫2龄幼虫及其卵囊的孵化具有较好的抑制作用，对土壤中自由生活的小杆线虫毒性微弱；H-2菌株代谢物5倍液处理24 h后，对南方根结线虫2龄幼虫的致死率达74.35%，卵囊孵化抑制率为78.46%，H-2菌株具有较高应用价值。%A strain H-2 was isolated by diluted solution method from soybean continuous cropping soil sample,its morphological,physiological and biochemical characteristics were identified and 16S rDNA was analyzed. The result showed that it was Streptomyces parvus. Fermentation filtrates of Streptomyces parvus at different concentrations were evaluated for nematicidal activity against Meloidogyne incognita and Rhabditis sp. in laboratory. Fermentation filtrates of the strains could suppress the egg hatching and 2nd-instar larvae of Meloido-gyne incognita. Culture filtrates of Strain H-2 showed a weak level of nematicidal activity of free-living Rhabditis sp. The corrected mortality rate of Meloidogyne incognita egg hatching and 2nd-instar larvae reached 74.35%and 78.46%,respectively by,strain H-2 at 5 diluted solution.