香蕉根际土壤解磷细菌的筛选、鉴定及解磷能力

Isolation, identification and phosphate solubilization analysis of phosphate-solubilizing bacteria derived from banana rhizosphere soil

【目的】以磷矿粉为难溶态磷,以期从香蕉根际土壤筛选出高效的解磷细菌。【方法】采用透明圈法和钼锑抗比色法分离筛选解磷细菌,通过形态学特征、生理生化试验结合16S r RNA基因序列分析及系统发育树比对鉴定其种属,并利用单因素试验方法研究不同碳源、氮源及C/N比值(40:1、20:1和8:1)对菌株溶解磷矿粉能力的影响。研究不同菌株解磷能力和培养介质p H值的变化关系。【结果】分离具有解磷能力的细菌8株,筛选出具有代表性的3个菌株B3-5-6、M-3-01和T1-4-01,初步鉴定菌株B3-5-6为嗜气芽孢杆菌(Bacillus aerophilus),M-3-01为虫内生沙雷氏菌(Serratia nematodiphila),T1-4-01为艾博丽肠杆菌(Enterobacter asburiae)。B3-5-6解磷能力与介质p H值之间存在线性负相关性(|r|=0.949 66>0.735),其相关性达到极显著水平;B3-5-6在碳源为蔗糖、氮源为(NH4)2SO4、C/N为40:1,M-3-01在碳源为葡萄糖、氮源为(NH4)2SO4、C/N为20:1,T1-4-01在碳源为乳糖、氮源为蛋白胨、C/N为20:1条件下解磷效果较好。解磷效果与初筛相比分别提高了1.12、1.17、2.55倍。【结论】不同的碳氮源、C/N值会直接影响磷细菌的解磷能力;筛选出一株解磷能力与培养介质p H之间存在着极显著相关性的细菌,其解磷机理有待进一步研究。

[Objective] In this study, ground phosphaterock was used as the undissolved phosphorus to select the high-efficient phosphate-solubilizing bacteria from the banana rhizosphere soil. [Methods] The methods of halo ring and Mo-Sb colorimetry were applied to isolate the phosphate-solubilizing bacteria. And a combination of morphologic alcharacteristics identification, physiological and biochemical test, 16 S rRNA gene sequences analysis and phylogenic trees were employed to determine the genus of the phosphate-solubilizing bacteria. Various sources of carbon or nitrogen, the C/N value（40：1, 20：1, 8：1） and the pH value of culture medium which may affect the bacteria＇s ability to dissolve the ground phosphate rock were studied with the single factor experimental method. [Results] Eight strains of phosphate-solubilizing bacteria（PSB） were isolated from the root soil, and three of them, B3-5-6, M-3-01, T1-4-01, were taken as representatives. The B3-5-6 was identified to be Bacillus aerophilus, M-3-01 Serratia nematodiphila and T1-4-01 Enterobacter asburiae. The phosphate-solubilizing ability of B3-5-6 and the pH of the culture medium was found to be linear negative correlated（｜r｜=0.949 66〉0.735） and reached the extremely significant level. For strain B3-5-6, the phosphate-solubilizing ability was better when the carbon source was sucrose, nitrogen source was（NH4）2SO4 and C/N was 40：1. For strain T1-4-01, the phosphate-solubilizing ability was better when the carbon source was glucose, nitrogen source was（NH4）2SO4 and C/N was 20：1. For strain M-3-01, the phosphate-solubilizing ability was better when the carbon source was glucose, nitrogen source was（NH4）2SO4 and C/N was 20：1 for strain T1-4-01, the phosphate-solubilizing ability was better when the carbon source was lactose, nitrogen source was peptone and C/N was 20：1. The phosphate-solubilizing ability was raised 1.12 fold, 1.17 fold and 2.55 fold, respectively. [Conclusion] Various sources of carbon or nitrogen, and C/N could affect the phosphate-solubilizing ability of different strains. The phosphate-solubilizing ability of B3-5-6 and the pH of the culture medium was found to be linear negative correlated（｜r｜=0.949 66〉0.735） and reached the extremely significant level. The phosphate-solubilizing mechanism of this strain needs to be furtherly investigated.