Screening, cloning and expression patterns of phosphorus-related genes of Burkholderia multivorans WS-FJ9 at different phosphorus levels

As important plant growth promoting rhizobacteria, phosphate-solubilizing bacteria (PSB) fix nitrogen, dissolve potassium, promote growth, improve the soil micro-environment, and enhance soil fertility. A high-efficiency PSB strain from the pine tree rhizosphere, Burkholderia multivorans WS-FJ9, was screened in our laboratory. In this study, using a Bio Screener fully automatic microbial growth curve meter to determine the growth of the WS-FJ9 strain in phosphate-removing medium, the growth and mineral phosphate solubilization of WS-FJ9 were obtained by Mo-Sb colorimetry and organophosphate-degradation plate assays. Second-generation sequencing technology was used to obtain genomic information and analyze possible phosphorus decomposition genes. The related expression of these genes under different phosphorus levels was determined by quantitative real-time PCR. The results showed that WS-FJ9 had strong adaptability and capacity for mineral phosphate solubilization at low phosphorus levels, which is characterized by its low phosphorus induction and high phosphorus inhibition. And the amount of solubilized mineral phosphate could exceed 140 mg/L. The total length of the genome of WS-FJ9 was 7,497,552 bp after splicing, and the GC content was 67.37%. Eight phosphate-related genes were selected to determine their expression patterns at different phosphorus levels. Among them, AP-2, GspE and GspF were only related to organic phosphorus, HlyB was only related to inorganic phosphorus, and PhoR, PhoA, AP-1 and AP-3 were related to both. The WS-FJ9 strain utilizes multiple pathways for mineral phosphate solubilization, and the degradation processes of different phosphorus sources are interrelated and independent, indicating that WS-FJ9 strain can adapt to different phosphorus source environments and has good potential for future applications.