The potential for polyphosphate metabolism in Archaea and anaerobic polyphosphate formation inMethanosarcina mazei

Abstract

AbstractInorganic polyphosphate (polyP) is ubiquitous across all forms of life, but the study of its metabolism has been mainly confined to bacteria and yeasts. Few reports detail the presence and accumulation of polyP in Archaea, and little information is available on its functions and regulation. Here, we report that homologs of bacterial polyP metabolism proteins are present across the major taxa in the Archaea, suggesting that archaeal populations may have a greater contribution to global phosphorus cycling than has previously been recognised. We also demonstrate that polyP accumulation can be induced under strictly anaerobic conditions, in response to changes in phosphate (Pi) availability, i.e. Pi starvation, followed by incubation in Pi replete media (overplus), in cells of the methanogenic archaeonMethanosarcina mazei. Pi-starvedM. mazeicells increased transcript abundance of the PHO-regulated alkaline phosphatase (phoA) gene and of the high-affinity phosphate transport (pstSCAB-phoU) operon: no increase in polyphosphate kinase 1 (ppk1) transcript abundance was observed. Subsequent incubation of Pi-starvedM. mazeicells under Pi replete conditions, led to a 237% increase in intracellular polyphosphate content and a >5.7-fold increase inppk1gene transcripts.Ppk1expression inM. mazeithus appears not to be under classical PHO regulon control.