辣木根际土壤溶磷菌的筛选与鉴定

Screening and Identification of Phosphorus-solubilizing Bacteria in Rhizosphere Soil of Moringa oleifera Lam.

【目的】磷是限制辣木生产力的重要因素之一。在酸性土壤严重缺磷的华南地区,施用溶磷菌能提高土壤中难溶态磷的有效性,促进植物生长发育,减少环境污染。【方法】以辣木根际土壤为研究对象,分离溶磷细菌并通过透明圈法筛选和钼锑抗比色法测定,初步筛选有解磷能力的菌株。结合菌落形态特征和16SrDNA高通量测序进一步鉴定优势溶磷菌。【结果】初步筛选到19株具有解有机磷和10株解无机磷能力的菌株,对卵磷脂和磷酸钙的最大溶磷量分别为26.95、13.48 mg/L, 溶磷量与pH呈负相关,但相关性不显著。进一步筛选了优势有机和无机溶磷菌菌株各2株,分别鉴定为巨大芽孢杆菌和蜡样芽孢杆菌、枯草芽孢杆菌和假单胞菌。此外,16S rDNA高通量测序结果表明,分离的辣木根际土壤微生物溶磷菌主要为类芽孢杆菌属、贪铜菌属、杆菌属、细杆菌属、根瘤菌属、根瘤菌等,其中芽孢杆菌属的丰度最高。【结论】分离筛选的优势溶磷菌可用于溶磷菌肥的开发和应用,为改善辣木根系环境和提高生产力提供菌株资源。

【Objective】Phosphorus is one of the important factors limiting the productivity of Moringa oleifera Lam. In southern China, where there is severe phosphorus deficiency in acid soil, the application of phosphorus-solubilizing bacteria can improve the effectiveness of insoluble phosphorus in soil, improve plant growth and reduce environmental pollution.【Method】The rhizosphere soil of M. oleifera Lam was chosen as the research material, and the phosphorussolubilizing bacteria was isolated, then screened by of clarity circle method and determined by molybdenum anti-colorimetric method. The strains with phosphorus dissolving ability were preliminarily isolated, and the dominant phosphorus-solubilizing bacteria was further identified by colony morphological characteristics and 16S rDNA high-throughput sequencing.【Result】 19 strains with organophosphorus dissolving ability and 10 strains with inorganic phosphorus dissolving ability were identified. The maximum phosphorus solubilizing content of lecithin and calcium phosphate by organic and inorganic phosphorus-solubilizing bacteria strains were 26.95 mg/L and 13.48 mg/L, respectively. The amount of phosphorussolubilizing bacteria was not significantly negatively correlated with pH. Two dominant organophosphorus-dissolving strains and two inorganic phosphorus dissolving strains were identified as Bacillus megaterium, Bacillus cereus, Bacillus subtilis and Pseudomonas, respectively. In addition, the result of 16S rDNA high-throughput sequencing showed that the microbial phosphate-dissolving bacteria isolated from the rhizosphere soil of M. oleifera Lam were mainly Paenibacillus, Cupriavidus, Bacillus, Microbacterium, Rhizobium, Mesorhizobium, etc. among which the abundance of Bacillus was the highest【. Conclusion】 The dominant phosphorus-solubilizing bacteria isolated and screened can be used for the development and application of phosphorus-solubilizing bacteria fertilizer, which provides strain resources for improving the root system environment and increasing the productivity of Moringa oleifera Lam.