一株鱼类水霉病原拮抗菌JL50分离鉴定及其拮抗特性分析

【目的】分离获得对鱼类水霉病原菌有较强拮抗作用的拮抗菌,分析水霉拮抗菌的拮抗特性,研究新疆鱼类水霉病的生物防治方法。【方法】以实验室分离获得的高致病性鱼类水霉病原菌株LF04为指示菌,从健康鲤鱼(Cyprinus carpio)体表分离获得对LF04有较强拮抗力的拮抗菌JL50,应用传统分类鉴定方法与分子鉴定法结合对该菌进行鉴定,并对该拮抗菌进行安全性、拮抗稳定性以及拮抗范围测试。【结果】鉴定拮抗菌JL50为芽孢杆菌科,芽孢杆菌属,短小芽孢杆菌(Bacillus pumilus);拮抗菌JL50对鱼苗安全,且将鱼苗的存活率提高了12%;对水霉病原菌孢子悬液的感染具有较强的拮抗作用,实验7 d时,实验组与对照组累积感染率分别为53.3%和95.0%,差异显著(P<0.05);经10代传代后拮抗性无减弱;拮抗谱测试表明,其拮抗性具有特异性。【结论】从健康鲤鱼体表分离出的拮抗菌JL50对特定水霉菌的生长有显著抑制作用,在渔业生防中具有潜在的开发应用价值。

Isolation and Identification of an Antagonistic JL50 for Saprolegniasis of Fish and Analysis of Its Antagonistic Characteristics

【Objective】 To isolate and obtain the antagonistic bacteria with strong antagonistic effect on the pathogen of Saprolegniasis, analyze the antagonistic characteristics of Saprolegniasis antagonistic bacteria, and discuss the biological control method in Xinjiang.【Method】In this study, the highly pathogenic fungus Saprolegnia LF04 isolated from the laboratory were used as the indicator bacteria. And the antagonistic bacteria JL50 with strong antagonism against LF04 was isolated from the body surface of the healthy carp (Cyprinus carpio). The antagonistic bacteria were identified by traditional classification and molecular identification methods, and the safety, antagonistic stability and antagonistic range of the antagonistic bacteria were tested.【Result】The antagonistic bacteria JL50 was identified as Bacillus family, Bacillus subtilis genus and Bacillus pumilus by traditional classification and molecular classification. The safety of the antagonist, the stability of the antagonism and the test of the antagonistic range were carried out. The results showed that this strain was safe for fry and increased the survival rate of the fry by 12%, and had a strong antagonism to the infection of the spore suspension of Saprolegnia. At the time of experiment 7 d, the cumulative infection rate of Saprolegniasis in the experimental group and the control group was 53.3% and 95%, and the difference was significant (P<0.05).And after 10 generations of passage, the antagonism was not weakened.【Conclusion】The antagonistic bacteria JL50 isolated from the body surface of healthy carp has a significant inhibitory effect on the growth of specific water mold and has potential development and application value in fishery biocontrol.