几株解纤维素生防芽孢杆菌的分子鉴定及其抗逆促生特性分析

Molecular identification of cellulose-degrading bio-control Bacillus strains and their stress-resistance and growth-promoting characteristics

【目的】探究青藏高原解纤维素生防芽孢杆菌资源。【方法】采用BOX-PCR指纹图谱分析、gyr B基因及16S r RNA基因序列分析,对分离自青海互助北山桦树根围的5株芽孢杆菌进行分子鉴定;通过CMC法检测菌株降解纤维素活性;平板对峙法检测菌株拮抗病原真菌及病原细菌活性;检测菌株的耐盐性、低温适生性;测定菌株促种子萌发及幼苗生长特性。【结果】5株菌均鉴定为解淀粉芽孢杆菌Bacillus amyloliquefaciens;具有显著降解纤维素的特性,在CMC平板上形成纤维素降解透明圈直径≥20 mm;对油菜菌核病菌(Sclerotinia sclerotiorum)、瓜类枯萎病菌(Fusarium oxysporum)、水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae)及植物梨火疫病菌(Erwinia amylovora)均有显著拮抗活性;菌株可在含Na Cl浓度为11%的LB平板上正常生长,在10°C低温条件下生长良好;菌株BS11、BS12菌悬液(细胞浓度106 CFU/m L)可促进水稻种子萌发及幼苗生长。【结论】5株B.amyloliquefaciens菌株为抗逆性强的、具有降解纤维素活性的生防芽孢杆菌,在青藏高原生态农业及畜牧产业中具有应用潜力。

[Objective] Bio-control Bacillus resource with cellulose-degrading research in special ecological environment of Qinghai-Tibetan Plateau was explored in this research. [Methods] Five Bacillus strains isolated from rhizosphere of birch in Huzhu Northern Mountain of Qinghai Province, were identified by molecular taxonomy methods including BOX-PCR fingerprints, as well as gyr B and 16 S r RNA gene partial sequence analysis. Cellulose-degrading activity of these isolates were detected by CMC plate screening method, and antagonistic activity to pathogenic fungi and bacteria were checked by plate confrontation method. Furthermore, growth-promoting and stress-resistance activity of isolates including salt-resistance and low-temperature adaptability were tested. [Results] Five isolates were identified as Bacillus amyloliquefaciens and all of isolates presented distinguished cellulose-degrading activity and could form transparent zone（diameter ≥20 mm） of cellulose-degrading on CMC medium. Isolates presented distinct antagonistic activity and bio-control efficacy to Sclerotinia sclerotiorum, Fusarium oxysporum, Xanthomonas oryzae pv. oryzae and Erwinia amylovora. Strains could grow under the condition of 10 ℃ low-temperature as well as LB medium with 11% Na Cl concentration, and bacterial cell suspension（concentration of 106 CFU/m L） of strains BS11 and BS12 could promote seed germination and seedling-growth of rice. [Conclusion] Five B. amyloliquefaciens strains own advantage with stress-resistance, cellulose-degrading and bio-control characteristic, thus possess application potential in ecological agriculture and animal husbandry field in Qinghai Province.