Isolation, Characterization, and Genomic Elucidation of HRY1: An Unconventional but Highly Efficient Phosphate-Solubilizing Escherichia coli

Phosphate-solubilizing bacteria (PSB) are pivotal in the cycling of phosphorus within terrestrial ecosystems and hold great promise for sustainable agriculture. In this study, we report the isolation of HRY1—a highly efficient phosphate-solubilizing strain—identified as Escherichia coli, a bacterium not traditionally recognized for plant-beneficial traits. Under optimized conditions (glucose as carbon source, (NH4)2SO4 as nitrogen source, pH 7.0, 1% inoculum, and 5 g/L Ca3(PO4)2), HRY1 consistently solubilized ~16% of inorganic phosphorus, with peak activity coinciding with its stationary growth phase (14 h). Whole-genome sequencing revealed a comprehensive genetic toolkit for phosphorus mobilization, including eight genes implicated in organic acid-mediated mineral dissolution, five high-affinity phosphate transporter genes (pit and pst gene cluster), and three two-component regulatory systems responsive to phosphate starvation (e.g., phoBR). The functional integration of these systems suggests a multifaceted strategy combining acidification, active uptake, and adaptive regulation to thrive under phosphorus limitation. Our findings redefine the ecological scope of E. coli and uncover an unconventional yet potent PSB candidate with significant potential for biofertilizer development and soil phosphorus activation. This discovery reveals E. coli’s untapped potential for phosphorus solubilization, with HRY1’s novelty residing in its high efficiency under optimized conditions and its practical promise as a biofertilizer.