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从河南南阳不同农田的植物根部采取土壤样本,共分离获得了198株细菌。通过毒性测试和平板生测从中筛选出松材线虫生防细菌6株,其中NS-3菌株对松材线虫的杀灭活性最高。结合该菌株的形态学、生理学特征及16S rDNA序列分析等结果将该菌株归为芽孢杆菌属,命名为Bacillus sp.strain NS-3。将该细菌液体培养的上清液和上清蛋白粗提物分别处理松材线虫48h后线虫的死亡率分别达到50%和100%;线虫死亡后虫体消解。然而,细菌的上清蛋白粗提物经煮沸变性后,基本丧失了对松材线虫的侵染活性,结果显示细菌Bacillus sp.strain NS-3的杀线虫活性物质主要要存在于细菌培养上清液中,并且为热不稳定性物质。
Soil samples were taken from the plant roots of different farmlands in Nanyang, Henan Province, and 198 strains of bacteria were isolated. Six strains of biocontrol bacteria of Bursaphelenchus xylophilus were screened out through toxicity test and tablet test, among which NS-3 strain had the highest killing activity against Bursaphelenchus xylophilus. According to the morphological, physiological characteristics and 16S rDNA sequence analysis, the strain was classified as Bacillus and named as Bacillus sp. Strain NS-3. The bacterial liquid culture supernatant and supernatant protein were treated pine wood nematode 48h after the mortality of nematodes were 50% and 100%; worm died after the body digestion. However, the crude extract of the bacterial supernatant boiled and denatured and basically lost its activity against the pine wood nematode. The results showed that the nematicidal active substance of the bacterium Bacillus sp. Strain NS-3 mainly existed in the bacterial culture supernatant Liquid, and is a thermally unstable material.