摘要
试验以寄生水霉Saprolegnia parasitica为靶标菌,通过平板对峙及发酵液抑菌试验筛选获得一株拮抗菌FX11,其抑菌带平均宽度达18.30±1.52 mm,发酵液抑菌率为68.40%。试验通过形态学特征及16S rRNA基因序列分析对该菌株进行鉴定,并研究其安全性和抑菌稳定性。结果显示,该菌株为Streptomyces polychromogenes;其发酵液对散鳞镜鲤、彭泽鲫、大鳞副泥鳅3种淡水鱼稚鱼的存活率无显著影响(P>0.05);拮抗菌FX11经10次传代后抑菌效果未发生显著变化(P>0.05);其发酵液经不同温度处理后,抑菌活性变化差异不显著(P>0.05);pH变化对拮抗菌发酵液抑菌活性影响显著(P<0.05),拮抗菌发酵液在pH 6.0~8.0范围内抑菌率最高。研究结果表明,菌株Streptomyces polychromogenes FX11对水霉病原菌具有显著拮抗作用,且传代稳定,其发酵液对试验鱼苗安全,具有较好的热稳定性和酸碱适应性,在水霉病生物防治中具有良好的应用价值。
An antagonistic strain FX11 was screened by plate confrontation and fermentation broth bacteriostatic test. The average width of bacteriostatic band was 18.30 ±1.52 mm, and the bacteriostatic rate of fermentation broth was 68.40%. The strain was identified by morphological characteristics and 16 S rRNA gene sequence analysis, and its safety and antibacterial stability were studied. The results showed that strain FX11 was Streptomyces polychromogenes, and its fermentation liquid had no significant effect on the survival rate of test fish. There was no significant change in the bacteriostatic effect of antagonistic FX11 after 10 passages(P>0.05), and there was no significant difference in the bacteriostatic activity of the fermentation broth treated with different temperatures(P>0.05). The pH change had a significant effect on the antibacterial activity of antagonistic fermentation broth(P<0.05), and the inhibitory rate of antagonistic fermentation broth was the highest in the range of pH 6.0-8.0. The results show that strain Streptomyces polychromgenes FX11 have significant antagonistic effect on the Saprolegnia, and its passage is stable. Its fermentation liquid is safe for the experimental fish, have good thermal stability and acid-base adaptability. The strain has good application value in the biological control of Saprolegnia.
作者
王旭
王丹生
罗永成
WANG Xu;WANG Dan-sheng;LUO Yong-cheng(Agriculture College of Eastern Liaoning University,Coastal Biotechnology Institute of Eastern Liaoning University,Dandong 118003,China)
出处
《浙江海洋大学学报（自然科学版）》
CAS
北大核心
2019年第6期481-486,共6页
Journal of Zhejiang Ocean University：Natural Science
基金
辽宁省自然科学基金指导计划项目(20180550414)
辽宁省教育厅科学技术研究项目(ldxy2017016)。
