Revealing the phosphate-solubilizing characteristics and mechanisms of the plant growth-promoting bacterium Agrobacterium deltaense C1.

This article focuses on the phosphate (Pi)-solubilizing characteristics and mechanisms of a novel bacterium, *Agrobacterium deltaense* C1, isolated from the rhizosphere of *Brassica napus*. The study demonstrates that strain C1 significantly promotes *Arabidopsis thaliana* growth under phosphorus-deficient conditions by solubilizing insoluble phosphate primarily through the secretion of organic acids, especially gluconic acid, which accounts for the majority of its Pi-solubilizing effect. Notably, C1’s phosphate solubilization and expression of the glucose dehydrogenase (gcd) gene remain effective even in the presence of available phosphate, distinguishing it from many other phosphate-solubilizing bacteria. Additionally, C1 produces multiple plant growth-promoting substances, suggesting its potential as a microbial biofertilizer to enhance crop growth in P-deficient soils.