Four phosphate rock-solubilizing bacteria (PRSB) ( Asaia lannensis Vb1, Pseudomonas sp . Vr14, Rahnella sp . Sr24, and Pantoea sp . Vr25) isolated from the mycorrhizosphere of maize were evaluated as inoculants, individually or in different combinations, together with Rhizophagus irregularis DAOM 197198, under greenhouse conditions. To create an effective bacterial mix for P solubilization and growth promotion, parameters such as the ability of the strains (individually or in mixture) to mobilize phosphate rock (PR), their biocompatibility, and their capacity for biofilm formation over PR particles and root colonization were tested. Accompanying PR solubilization, the bacteria produced organic acids and reduced the pH of the medium, produced exopolysaccharides, and had variable capacity to colonize the roots of maize plantlets. In low-phosphorus soil amendment with PR, all strains, regardless of their capacity to solubilize PR, increased dry weight, nutrient (N, P, and K) uptake, and the percentage of indigenous arbuscular mycorrhizae (iAM) root colonization in maize plants, compared to the non-inoculated control. However, mixed inoculation of the strains showed significantly better results. Addition of Rhizophagus irregularis resulted in further growth stimulation. Overall results showed that two combinations— Rahnella sp . Sr24 + Pantoea sp . Vr25 + R. irregularis , and Pantoea sp . Vr25 + Pseudomonas sp . Vr14 + R. irregularis —were better inoculants. We concluded that an effective PRSB combination of biocompatible strains with capacity for PR solubilization, successful biofilm formation, effective root colonization, different growth promotion traits, and the addition of AM has potential as inoculants for more sustainable agriculture in low-phosphorus soils amended with low-reactivity PR.

中文翻译：

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设计与丛枝菌根相容的多菌种溶磷菌接种剂促进低磷土壤植物生长

从玉米的菌根圈中分离出的四种磷酸盐岩溶解细菌 (PRSB)（Asaia lannensis Vb1、假单胞菌属 Vr14、Rahnella sp. Sr24 和 Pantoea sp. Vr25）作为接种剂，单独或以不同的组合与根霉一起评估不规则 DAOM 197198，在温室条件下。为 P 溶解和促进生长创造有效的细菌混合物，参数如菌株（单独或混合）动员磷矿 (PR) 的能力、它们的生物相容性以及它们在 PR 颗粒上形成生物膜和根定植的能力进行了测试。随着 PR 溶解，细菌产生有机酸并降低培养基的 pH 值，产生胞外多糖，并具有不同的能力来定植玉米幼苗的根部。在含 PR 的低磷土壤改良剂中，所有菌株，无论其溶解 PR 的能力如何，都增加了干重、养分（N、P 和 K）吸收，以及玉米植物中本土丛枝菌根 (iAM) 根部定植的百分比，与未接种的对照相比。然而，菌株的混合接种显示出明显更好的结果。加入不规则根瘤菌导致进一步的生长刺激。总体结果表明，两种组合——Rahnella sp . Sr24 + Pantoea sp。Vr25 + R。不规则，和泛菌属。Vr25 + 假单胞菌属。Vr14 + R.informalis — 是更好的接种剂。我们得出结论，生物相容性菌株的有效 PRSB 组合具有 PR 溶解能力、成功的生物膜形成、有效的根系定植、不同的生长促进特性，