Dynamic polyphosphate metabolism in cyanobacteria responding to phosphorus availability

Abstract

Summary Despite the crucial role of polyphosphate (polyP) in aquatic environments, its metabolism in cyanobacteria responding to nutrients is poorly understood. We investigate polyP in three cyanobacteria species, specifically unicellular picocyanobacteria, under various nutritional conditions. Our experiments show that the accumulation of polyP in cyanobacteria is strongly dynamic, depending on phosphate levels and growth stages. ‘Overplus’ uptake of phosphorus (P) during the lag phase leads to the rapid accumulation of polyP, followed by lower polyP quotas during the exponential growth stage as a result of competing ‘luxury’ P uptake and polyP utilization to support rapid cell division. Cyanobacteria are capable of P deficiency responses that preferentially maintain polyP. However, preferential utilization of polyP occurs under severe P stress, suggesting the crucial role of polyP as P reserve to support cellular survival. Strong variability was observed among different species of cyanobacteria in their ability to accumulate polyP, and likely in the threshold P levels at which preferential polyP degradation occurs. This suggests that some cyanobacteria may be more adaptive to P‐stressed or P‐fluctuating conditions. Our results explain and provide important insights into the variability of polyP observed in aquatic environments where picocyanobacteria are the dominant primary producers.

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).…”

Picoplankton accumulate and recycle polyphosphate to support high primary productivity in coastal Lake Ontario

“…Phytoplankton are also known to accumulate polyphosphate (polyP), a polymer containing three to hundreds of orthophosphate units. The physiological functions of polyP associated with nutrient stringency have been suggested in culture studies 12,13 . PolyP exhibits complex dynamics in cells 13,14 : when P is abundant, cells take up P in excess of what is required for growth to accumulate polyP, a process called “luxury uptake” 13,14 .…”

“…The physiological functions of polyP associated with nutrient stringency have been suggested in culture studies 12,13 . PolyP exhibits complex dynamics in cells 13,14 : when P is abundant, cells take up P in excess of what is required for growth to accumulate polyP, a process called “luxury uptake” 13,14 . Cells then can use this polyP to support metabolic processes and growth when P is scarce 13,15 .…”

“…PolyP exhibits complex dynamics in cells 13,14 : when P is abundant, cells take up P in excess of what is required for growth to accumulate polyP, a process called “luxury uptake” 13,14 . Cells then can use this polyP to support metabolic processes and growth when P is scarce 13,15 . PolyP also helps cell restoration via a process called “overplus response”: when P-stressed cells experience a P resupply, they take up P rapidly to produce polyP to support recovery from P deficiency 13,15,16 .…”

“…Cells then can use this polyP to support metabolic processes and growth when P is scarce 13,15 . PolyP also helps cell restoration via a process called “overplus response”: when P-stressed cells experience a P resupply, they take up P rapidly to produce polyP to support recovery from P deficiency 13,15,16 .…”