TY - JOUR

T1 - Strain-Specific Phosphate Mobilization in Enterobacter: Organic Acid Production and Genomic Architecture of Solubilization Mechanisms

AU - Sokolova, Ekaterina Alexeevna

AU - Khlistun, Inna Viktorovna

AU - Mishukova, Olga Viktorovna

AU - Tromenschleger, Irina Nikolaevna

AU - Chumanova, Evgeniya Vladimirovna

AU - Voronina, Elena Nikolaevna

N1 - This work was supported by the Ministry of Science and Higher Education of the Russian Federation (the Federal Scientific-technical programme for genetic technologies development for 2019–2030, agreement N. 075-15-2025-473).

PY - 2025/12/27

Y1 - 2025/12/27

N2 - Phosphate-solubilizing microorganisms (PSMs) show promise for sustainable agriculture, yet inconsistent field performance limits their application. We investigated phosphate solubilization mechanisms in Enterobacter ludwigii strains GMG278, GMG291, GMG378 and Enterobacter soli GMG1156 through greenhouse wheat experiments, high-performance liquid chromatography (HPLC) organic acid analysis, and comparative genomics. Greenhouse trials demonstrated that bacterial inoculation compensated for phosphorus deficiency, with GMG291, GMG1156, and GMG278 showing superior performance. HPLC identified malic acid as the predominant secreted organic acid, with E. soli producing threefold higher concentrations than E. ludwigii strains. Phosphate solubilization efficiency followed the order FePO4 > AlPO4 > Ca3(PO4)2, with maximal release (95.9-97.7 μg/mL) from iron phosphate despite lower malic acid secretion, suggesting siderophore involvement. An inverse correlation between malic acid levels and soluble phosphate concentrations likely reflects competitive bacterial phosphate uptake and secondary precipitation processes. Comparative genomics revealed missense mutations in the LuxR transcriptional regulator of strain GMG378 (Asp86Asn and Arg97Leu) near predicted DNA-binding domains, correlating with reduced solubilization capacity. Phosphate solubilization in Enterobacter proceeds primarily through metal-malic acid complex formation, with strain-specific efficiency linked to LuxR-regulated biofilm formation genes. These findings suggest PSM screening should incorporate biofilm-related genetic markers alongside acid production measurements.

AB - Phosphate-solubilizing microorganisms (PSMs) show promise for sustainable agriculture, yet inconsistent field performance limits their application. We investigated phosphate solubilization mechanisms in Enterobacter ludwigii strains GMG278, GMG291, GMG378 and Enterobacter soli GMG1156 through greenhouse wheat experiments, high-performance liquid chromatography (HPLC) organic acid analysis, and comparative genomics. Greenhouse trials demonstrated that bacterial inoculation compensated for phosphorus deficiency, with GMG291, GMG1156, and GMG278 showing superior performance. HPLC identified malic acid as the predominant secreted organic acid, with E. soli producing threefold higher concentrations than E. ludwigii strains. Phosphate solubilization efficiency followed the order FePO4 > AlPO4 > Ca3(PO4)2, with maximal release (95.9-97.7 μg/mL) from iron phosphate despite lower malic acid secretion, suggesting siderophore involvement. An inverse correlation between malic acid levels and soluble phosphate concentrations likely reflects competitive bacterial phosphate uptake and secondary precipitation processes. Comparative genomics revealed missense mutations in the LuxR transcriptional regulator of strain GMG378 (Asp86Asn and Arg97Leu) near predicted DNA-binding domains, correlating with reduced solubilization capacity. Phosphate solubilization in Enterobacter proceeds primarily through metal-malic acid complex formation, with strain-specific efficiency linked to LuxR-regulated biofilm formation genes. These findings suggest PSM screening should incorporate biofilm-related genetic markers alongside acid production measurements.

KW - malic acid

KW - mechanism of phosphate solubilization

KW - phosphate-solubilizing microorganisms

KW - syntenic analysis of the genomes

UR - https://www.scopus.com/pages/publications/105027194649

UR - https://www.mendeley.com/catalogue/e22f9af2-bf9b-3a7d-a3fc-668eb8fd1981/

U2 - 10.3390/ijms27010322

DO - 10.3390/ijms27010322

M3 - Article

C2 - 41516198

VL - 27

JO - International Journal of Molecular Sciences

JF - International Journal of Molecular Sciences

SN - 1661-6596

IS - 1

M1 - 322

ER -