The PolS-PolR Two-Component System Regulates Genes Involved in Poly-P Metabolism and Phosphate Transport in Microlunatus phosphovorus

Abstract

Microlunatus phosphovorus NM-1 is a polyphosphate (poly-P)-accumulating bacterium that accumulates poly-P under aerobic conditions and degrades poly-P under anaerobic conditions. In this study, the two-component system (TCS) PolS-PolR was identified in NM-1, and the response regulator PolR was found to directly bind to the promoters of genes related to phosphate transport (MLP_RS00235, MLP_RS23035, and MLP_RS24590); poly-P catabolism (MLP_RS12905) and poly-P synthesis (MLP_RS23025). RT-qPCR assays showed that ppgk (MLP_RS12905), ppk (MLP_RS23025), pstS (MLP_RS23035), and pit (MLP_RS24590) were down-regulated during the aerobic-anaerobic shift. The sequence GTTCACnnnnnGTTCaC was identified as a recognition sequence for PolR by MEME analysis and DNase I footprinting. EMSAs and ChIP-qPCR assays indicated that PolR binds to the promoters of pit (MLP_RS00235), ppgk (MLP_RS12905), ppk (MLP_RS23025), pstS (MLP_RS23035) and pit (MLP_RS24590), and ChIP-qPCR further suggested that the binding affinity of PolR was lower under anaerobic conditions than under aerobic conditions in vivo. These findings indicate that the PolS-PolR TCS in M. phosphovorus may be involved in the regulation of poly-P metabolism in response to levels of dissolved oxygen in the environment, and our results provide insights into new approaches for understanding the mechanisms of phosphorus accumulation and release.

Role of EmaSR in Ethanol Metabolism by Acinetobacter baumannii

“…The RspA1 knock-out mutant, ΔrspA1 , in Streptomyces albus demonstrated lower biomass accumulation and lower glucose consumption rates as compared to the parental strain A30 when cultivated in a defined minimal medium (MM) complemented with 75 mM glutamate [ 24 ]. The PolS-PolR TCS, identified in Microlunatus phosphovorus NM-1, was shown to regulate polyphosphate catabolism, and the response regulator PolR was found to directly bind to the promoters of genes involved in phosphate transport [ 25 ]. These examples outline the extent to which TCS regulation is present in bacterial metabolism.…”

Isolation and Characterization of Phosphorus Solubilizing Bacteria With Multiple Phosphorus Sources Utilizing Capability and Their Potential for Lead Immobilization in Soil

“…To our knowledge, this is the first report that the solubilization of inorganic insoluble phosphorus is coupled with the synthesis of polyphosphate. It has been reported that polyphosphate regarded as high-energy compound could be hydrolyzed when phosphorus accumulating bacteria undergo undernourished conditions (Wan et al, 2017;Li and Dittrich, 2019;Zhong et al, 2019). Previous literatures have reported that some bacteria belonging to Acinetobacter genus harbor the ability to synthesize polyphosphate and could be regarded as phosphorus accumulating bacteria (Keating et al, 2016;Han et al, 2018).…”

Maize-soybean intercropping facilitates chemical and microbial transformations of phosphorus fractions in a calcareous soil

“…This implies that bacteria-mediated P o cycling was enhanced in the rhizosphere of these crops, although the total P o contents increased for both crops under the NB treatment ( Table 2 ). In addition, Microlunatus facilitates the formation and accumulation of polyphosphate ( Zhong et al, 2019 ). The enriched Microlunatus positively correlated with the Ca 8 -P i fraction, but negatively correlated with the Ca 2 -P i , Al-P i and Fe-P i fractions in both maize and soybean rhizospheres ( Figures 1B , 2B ), suggesting that Microlunatus may be involved in transformation of Ca 2 -P i , Al-P i and Fe-P i fractions into the Ca 8 -P i fraction through the formation of polyphosphate by Microlunatus and the subsequent hydrolysis of polyphosphate to replenish Ca 2 -P i , Al-P i and Fe-P i pools.…”