Redox-active antibiotics enhance phosphorus bioavailability

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Science  05 Mar 2021:
Vol. 371, Issue 6533, pp. 1033-1037
DOI: 10.1126/science.abd1515

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Phenazines liberate phosphate

Bacteria secrete a wide range of small molecules with chemical reactivity that offers multiple functions in different contexts. Phenazines are commonly considered to be antibiotics, but they can also participate in environmental redox reactions, especially with iron. McRose and Newman found that phenazines, when added exogenously or made by bacteria in situ, can liberate phosphorous (P) in the form of phosphate from mineral surfaces, and that the production of these molecules is regulated by signaling pathways that respond to P limitation. Strains unable to produce these molecules grew more slowly under P limitation but could be rescued by the addition of exogenous phenazines. The authors hypothesize that reductive dissolution of iron oxides has the benefit of liberating P, and that this could be one mechanism of microbial P acquisition in some environments.

Science, this issue p. 1033


Microbial production of antibiotics is common, but our understanding of their roles in the environment is limited. In this study, we explore long-standing observations that microbes increase the production of redox-active antibiotics under phosphorus limitation. The availability of phosphorus, a nutrient required by all life on Earth and essential for agriculture, can be controlled by adsorption to and release from iron minerals by means of redox cycling. Using phenazine antibiotic production by pseudomonads as a case study, we show that phenazines are regulated by phosphorus, solubilize phosphorus through reductive dissolution of iron oxides in the lab and field, and increase phosphorus-limited microbial growth. Phenazines are just one of many examples of phosphorus-regulated antibiotics. Our work suggests a widespread but previously unappreciated role for redox-active antibiotics in phosphorus acquisition and cycling.

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