Characterization of the rhizosphere potassium-solubilizing Cupriavidus taiwanensis strain NKK10 by transcriptional profiling analysis

Potassium-solubilizing bacteria are microorganisms capable of dissolving potassium from potassium-containing minerals, with some species carrying the ability to promote plant growth. This study aims to explore the composition of potassium-solubilizing bacteria from the rhizosphere of wild Lespedeza floribunda, a representative Leguminosae plant, and the mechanisms underlying potassium release. Among the isolated bacteria, the Cupriavidus taiwanensis strain NKK10 exhibited highly efficient potassium solubilizing capacity from potassium feldspar, leading to potassium release of 0.35 and 0.57 mg/mL after 7 d and 14 d, respectively. Microscopic observation showed that the NKK10 cells were able to bind strongly to feldspar, resulting in the formation of a dense biofilm on the mineral surface. As revealed by mRNA sequencing and transcriptional profiling analysis, C. taiwanensis NKK10 drastically remodeled transcriptional profiling analysis in the feldspar medium, with upregulation of critical signaling pathways involved in interspecies interaction between organisms and biofilm formation in response to the stimulus of peptidoglycan synthesis. The results of this study extend our knowledge of the functional microorganisms in Leguminosae rhizospherie soil, and provide insights into the transcriptional regulation of potassium-solubilizing bacteria during the solubilization process.