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Title: Growth on ATP elicits a P-stress response in the picoeukaryote Micromonas pusilla

The surface waters of oligotrophic oceans have chronically low phosphate (Pi) concentrations, which renders dissolved organic phosphorus (DOP) an important nutrient source. In the subtropical North Atlantic, cyanobacteria are often numerically dominant, but picoeukaryotes can dominate autotrophic biomass and productivity making them important contributors to the ocean carbon cycle. Despite their importance, little is known regarding the metabolic response of picoeukaryotes to changes in phosphorus (P) source and availability. To understand the molecular mechanisms that regulate P utilization in oligotrophic environments, we evaluated transcriptomes of the picoeukaryote Micromonas pusilla grown under Pi-replete and -deficient conditions, with an additional investigation of growth on DOP in replete conditions. Genes that function in sulfolipid substitution and Pi uptake increased in expression with Pi-deficiency, suggesting cells were reallocating cellular P and increasing P acquisition capabilities. Pi-deficient M. pusilla cells also increased alkaline phosphatase activity and reduced their cellular P content. Cells grown with DOP were able to maintain relatively high growth rates, however the transcriptomic response was more similar to the Pi-deficient response than that seen in cells grown under Pi-replete conditions. The results demonstrate that not all P sources are the same for growth; while M. pusilla, a model picoeukaryote, may grow wellmore » on DOP, the metabolic demand is greater than growth on Pi. Lastly, these findings provide insight into the cellular strategies which may be used to support growth in a stratified future ocean predicted to favor picoeukaryotes.« less
Authors:
 [1] ;  [1]
  1. Bigelow Laboratory for Ocean Sciences, East Boothbay, ME (United States)
Publication Date:
OSTI Identifier:
1283057
Grant/Contract Number:
AC02-05CH11231
Type:
Accepted Manuscript
Journal Name:
PLoS ONE
Additional Journal Information:
Journal Volume: 11; Journal Issue: 5; Journal ID: ISSN 1932-6203
Publisher:
Public Library of Science
Research Org:
Bigelow Laboratory for Ocean Sciences, East Boothbay, ME (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES western north-atlantic; dissolved organic phosphorus; sargasso sea; saccharomyces-cerevisiae; phosphatase-activity; community structure; emiliania-huxleyi; marine systems; flow-cytometry; carbonic-acid