鲟源病原性嗜水气单胞菌拮抗芽孢杆菌的鉴定及其生物学特性

Identification and biological characteristics of a Bacillus strain antagonistic against pathogenic Aeromonas hydrophila of sturgeons

摘要:

从养殖池污泥中分离筛选了1株优良的鲟源嗜水气单胞菌拮抗芽孢杆菌G1, 其对鲟源嗜水气单胞菌S1产生的抑菌圈直径为18.50 mm。通过API50CH细菌鉴定系统以及16S rRNA序列分析法, 菌株G1被鉴定为解淀粉芽孢杆菌(Bacillus amyloliquefaciens), GenBank登录号HM245965.1, 其16S rRNA序列与基因库中芽孢杆菌属菌株的16S rRNA序列有99%?100%的同源性, 而且与解淀粉芽孢杆菌Ba-74501 (GenBank登录号: DQ422953.1)的亲缘关系最近。菌株G1的最适生长pH值为7, 最适生长温度为30 °C, 其在30 °C、200 r/min条件下的生长曲线为: 0?6 h为生长延迟期, 6?54 h为对数生长期, 54?90 h为稳定期, 90 h以后为衰亡期。此外, 菌株G1对其他实验选用的病原性嗜水气单胞菌也表现出良好的拮抗活性。本实验结果有利于填补嗜水气单胞菌拮抗菌在分类地位、生物学特性等方面的不足, 为鲟鱼嗜水气单胞菌病的生物防控提供科学资料。

Abstract:

A good Bacillus strain G1 antagonistic against pathogenic Aeromonas hydrophila of sturgeons was isolated and screened from the sediment of aquaculture ponds, which produced the inhibition zone of 18.50 mm in diameter against A. hydrophila strain S1. Strain G1 (GenBank accession number: HM245965.1) was identified as Bacillus amyloliquefaciens through APICH50 bacterial identification system and 16S rRNA sequence analysis. Its 16S rRNA sequence had homology of 99%?100% with those of Bacillus sp. strains submitted to GenBank, and showed the most close relative to Bacillus amyloliquefaciens strain Ba-74501 (GenBank accession number: DQ422953.1). The best growth pH and temperature of strain G1 were 7 and 30 °C, its growth curve in the condition of 30 °C and 200 r/min was as follows: the lag phase was 0?6 h, the log phase was 6?54 h, the stationary phase was 54?90 h, the decline phase was after 90 h. In addition, strain G1 also exhibited good antagonistic activity against other tested A. hydrophila strains. The experimental results were conductive to fill in the data gaps about the taxonomic position of antagonists against A. hydrophila, and provide scientific data to the biocontrol on sturgeon aeromonasis.