Biological nitrogen fixation and phosphate solubilization by bacteria isolated from tropical soils
Biological nitrogen fixation and phosphate solubilization by bacteria isolated from tropical soils
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DOI：
10.1007/s11104-012-1157-z
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发表时间：
2012-08-01
期刊：
影响因子：
4.9
通讯作者：
de Souza Moreira, Fatima Maria
中科院分区：
文献类型：
--
作者：
Marra, Leandro Marciano;Fonseca Sousa Soares, Claudio Roberto;de Souza Moreira, Fatima Maria
除了固定大气中的氮之外，一些细菌分离物还可以溶解不溶性磷酸盐，进一步促进植物生长。本研究的目的如下：分离、选择和鉴定豇豆中的结瘤细菌，这些细菌不仅在生物固氮（BNF）方面有效，而且在溶解不溶性无机磷酸盐方面也有效；识别并量化产生的有机酸；并建立这些酸与溶解能力之间的关系。使用豇豆 [Vigna unguiculata (L.) Walp.] 作为诱饵，从拉夫拉斯和帕托斯德米纳斯市的两种含有高浓度不溶性磷的土壤中捕获细菌。我们获得了 78 个菌株，根据其在培养基 79 中的培养属性进行了表征，其中包括菌株 UFLA 03-84、INPA 03-11B 和 BR3267（经畜牧和供应农业部 -MAPA 批准作为豇豆接种剂）和洋葱伯克霍尔德杆菌 (LMG1222(T))，用作磷酸盐溶解的阳性对照。通过 16S rDNA 序列分析鉴定了根据这两个过程的效率而选择的菌株。我们评估了温室中的共生效率 (BNF) 以及固体和液体 GELP 介质中 CaHPO4、Al(H2PO4)(3) 和 FePO4.2H(2)O 的溶解效率。还评估了擅长溶解这些磷酸盐来源的菌株产生以下有机酸：草酸、柠檬酸、葡萄糖酸、乳酸、琥珀酸和丙酸。通过 16S rDNA 测序和分析检测不动杆菌属、芽孢杆菌属、厚壁菌门、微杆菌属、类芽孢杆菌属和根瘤菌的存在。从豇豆根瘤中获得的细菌菌株在 BNF 和磷酸盐溶解过程中的效率差异很大，特别是在菌株 UFLA 03-09、UFLA 03-10、UFLA 03-12 和 UFLA 03-13 中，它们在这两个过程中都更有效。与固体培养基相比，更多的菌株能够在液体培养基中溶解不溶性无机磷酸钙和磷酸铁。对于某些菌株来说，有机酸的产生与 CaHPO4 和 FePO4.2H(2)O 的溶解有关，酸的类型和浓度影响这一过程。这些是从热带土壤中分离的细菌中获得的第一个结果，其中检测和定量了有机酸的产生，以检查不溶性无机磷酸盐的溶解。
In addition to fixing atmospheric nitrogen, some bacterial isolates can also solubilize insoluble phosphates, further contributing to plant growth.The objectives of this study were the following: isolate, select, and identify nodulating bacteria in the cowpea that are efficient not only in biological nitrogen fixation (BNF) but also in the solubilization of insoluble inorganic phosphates; identify and quantify the organic acids produced; and establish the relationship between those acids and the solubilizing capacity.The bacteria were captured from two soils containing high concentrations of insoluble phosphorus from the cities of Lavras and Patos de Minas, using the cowpea [Vigna unguiculata (L.) Walp.] as bait. We obtained 78 strains, which were characterized according to their cultural attributes in culture medium 79 with the strains UFLA 03-84, INPA 03-11B, and BR3267 (approved by the Ministry of Livestock and Supply Agriculture-MAPA, as inoculants for the cowpea) and Burkholderia cepacia (LMG1222(T)), which was used as a positive control for phosphate solubilization. Strains that were selected for their efficiency in both processes were identified by 16S rDNA sequence analysis. We evaluated the symbiotic efficiency (BNF) in a greenhouse and the solubilization efficiency of CaHPO4, Al(H2PO4)(3), and FePO4.2H(2)O in solid and liquid GELP media. Strains that excelled at the solubilization of these phosphate sources were also evaluated for the production of the following organic acids: oxalic, citric, gluconic, lactic, succinic, and propionic.The presence of Acinetobacter, Bacillus, Firmicutes, Microbacterium, Paenibacillus, and Rhizobium was detected by 16S rDNA sequencing and analysis. Bacterial strains obtained from cowpea nodules varied greatly in the efficiency of their BNF and phosphate solubilization processes, especially in the strains UFLA 03-09, UFLA 03-10, UFLA 03-12, and UFLA 03-13, which were more efficient in both processes. More strains were able to solubilize insoluble inorganic calcium and iron phosphates in liquid medium than in solid medium. The production of organic acids was related to the solubilization of CaHPO4 and FePO4.2H(2)O for some strains, and the type and concentration of the acid influenced this process.These are the first results obtained with bacterial isolates from tropical soils in which the production of organic acids was detected and quantified to examine the solubilization of insoluble inorganic phosphates.