摘要
通过平板对峙法及发酵液抑菌试验,从辽宁省东港市淡水池塘养殖的散鳞镜鲤等病鱼组织及其卵中分离出寄生水霉,从该地区淡水养殖池塘周围土壤样品中分离出21株放线菌,筛选出1株抗寄生水霉的拮抗菌FX17。通过形态学特征及16S rRNA基因序列系统发育分析初步鉴定拮抗菌FX17,并研究其抑菌稳定性。试验结果显示,筛选获得的拮抗菌FX17对水霉具有显著抑制作用,其抑菌带平均宽度达(25.40±0.13)mm,发酵液抑菌率为73.20%。拮抗菌FX17与链霉菌属细菌Streptomyces triostinicus具有较近的亲缘关系。经10次传代后,该拮抗菌抑菌效果未发生显著变化(P>0.05)。菌株FX17的发酵液经不同温度处理后,抑菌活性变化不显著(P>0.05),推测其拮抗物质活性成分为非蛋白质类代谢物。pH显著影响该拮抗菌发酵液抑菌活性(P<0.05),在pH 6.0~8.0内抑菌率最高。试验结果表明,菌株S.triostinicus FX17对水霉病原菌具有显著拮抗作用,传代稳定,其发酵液具有较好的热稳定性,在pH 6.0~8.0内抑菌活性稳定,具有开发成为水霉病生防菌株的潜在价值。
The parasitic aquatic mold(Saprolegnia parasitica)was isolated from diseased fish tissues such as mirror common carp Cyprinus carpio var.specularis and their eggs cultured in freshwater ponds in Donggang City,Liaoning Province,through the flat panel confrontation method and the fermentation broth bacteriostasis test.Twenty-one strains of actinomycetes were isolated from soil samples around freshwater ponds in the area above,and an antagonistic strain FX17 with significant inhibition on water mildew was screened and identified by morphological characteristics and phylogenetic analysis of 16S rRNA gene sequence.The results showed that the antagonistic FX17 had average width of bacteriostatic zone of(25.40±0.13)mm,and the fermentation broth bacteriostasis rate of 73.20%,showing significant inhibitory effect on water mold.The subculture showed that the strain FX17 had a close relationship with Streptomyces tristinicus,without significant change in the inhibition rate after 10 passages(P>0.05),and without significant difference in antimicrobial activity of FX17 fermentation broth treated with different temperatures(P>0.05),indicating that the active components of its antagonistic substances were not protein metabolites.The bacteriostatic activity of antagonistic fermentation broth was shown to be varied with change in pH value significantly(P<0.05),with the maximal bacteriostatic rate of antagonistic fermentation broth in the pH range of 6.0—8.0.The findings showed that S.triostinicus FX17 had potential value to develop into a biocontrol bacterial strain against water mildew.
作者
王旭
冯春明
孙述好
罗永成
WANG Xu;FENG Chunming;SUN Shuhao;LUO Yongcheng(College of Agriculture, Eastern Liaoning University, Dandong 118003, China;Institute of Coastal Biotechnology, Eastern Liaoning University, Dandong 118003, China;Dandong Fishery Development Service Center, Dandong 118000, China)
出处
《水产科学》
CAS
CSCD
北大核心
2020年第5期760-765,共6页
Fisheries Science
基金
辽宁省自然科学基金指导计划项目(20180551181)
辽宁省教育厅科学技术研究项目(ldxy2017016)。
