针茅内生细菌菌株265ZY4的鉴定及其生物学功能

【目的】为高寒草地针茅(Stipa capillata L.)内生细菌的开发和利用提供理论依据,为生物菌肥的研究提供有价值的菌种资源。【方法】利用常规分离方法从针茅中分离获得菌株265ZY4,采用平板对峙法、Salkowski比色法和钼锑抗比色法对该内生菌进行拮抗能力测定、产IAA以及溶磷、固氮能力测定。根据形态学和16S r RNA序列分析对菌株265ZY4进行鉴定,确定该菌株的分类学地位。【结果】菌株265ZY4对3种马铃薯真菌病害均有较好的抑制作用,且对马铃薯炭疽病(Colletotrichum coccodes)的拮抗作用最明显,抑菌率为83.03%;该菌株能分泌IAA,在不含色氨酸的培养基中的分泌量为9.30 mg/L,且有较好的溶解无机磷的能力,无固氮能力;通过培养性状和形态特征,结合16S r RNA序列分析,将菌株265ZY4鉴定为Bacillus subtilis。【结论】菌株265ZY4鉴定为枯草芽孢杆菌B.subtilis,具有溶磷、产IAA等生物学功能,具有开发潜力。

Identification and determination of biological functions of endophytic bacteria 265ZY4 from Stipa capillata

Objective] The result of this study will provide evidences for the exploration and utilization of plant endophyte from Stipa capillata on alpine meadow, and provide a valuable resource for the study of biological fertilizer. Methods] This test exploited the conventional methods of separation of endophytic bacteria 265ZY4 from Stipa capillata, and the strain was studied by 16S rRNA sequence analysis and biological characteristics including antibacterial activities, IAA secretion, phosphate solubilization and nitrogen fixation by using in vitro antagonistic tests, Salkowski colorimetry and Mo-Sb colorimetry. Results] Strain 265ZY4 demonstrated inhibitory activities to 3 fungal pathogens of potato, the best inhibitory rate of the strain were 83.03% against Colletotrichum coccodes. IAA was secreted by 265ZY4 as high as 9.30 mg/L in the King medium without addition of tryptophan, The strain also possessed the capacity of phosphate solubilization and without the capacity of nitrogen fixation. With the cultural and morphological characteristics, combined with 16S rRNA sequence analysis, the strain 265ZY4 was identified as Bacillus subtilis. Conclusion] Strain 265ZY4 was preliminarily identified as B. subtilis, and has the good biological function. It should be an interesting isolate for developing agriculture.