Display Settings:

Format

Send to:

Choose Destination
Proc Natl Acad Sci U S A. 2006 Aug 15;103(33):12552-7. Epub 2006 Aug 8.

Phosphate acquisition genes in Prochlorococcus ecotypes: evidence for genome-wide adaptation.

Author information

  • 1Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.

Abstract

The cyanobacterium Prochlorococcus is the numerically dominant phototroph in the oligotrophic oceans. This group consists of multiple ecotypes that are physiologically and phylogenetically distinct and occur in different abundances along environmental gradients. Here we examine adaptations to phosphate (P) limitation among ecotypes. First, we used DNA microarrays to identify genes involved in the P-starvation response in two strains belonging to different ecotypes, MED4 (high-light-adapted) and MIT9313 (low-light-adapted). Most of the up-regulated genes under P starvation were unique to one strain. In MIT9313, many ribosomal genes were down-regulated, suggesting a general stress response in this strain. We also observed major differences in regulation. The P-starvation-induced genes comprise two clusters on the chromosome, the first containing the P master regulator phoB and most known P-acquisition genes and the second, absent in MIT9313, containing genes of unknown function. We examined the organization of the phoB gene cluster in 11 Prochlorococcus strains belonging to diverse ecotypes and found high variability in gene content that was not congruent with rRNA phylogeny. We hypothesize that this genome variability is related to differences in P availability in the oceans from which the strains were isolated. Analysis of a metagenomic library from the Sargasso Sea supports this hypothesis; most Prochlorococcus cells in this low-P environment contain the P-acquisition genes seen in MED4, although a number of previously undescribed gene combinations were observed.

PMID:
16895994
[PubMed - indexed for MEDLINE]
PMCID:
PMC1567916
Free PMC Article

Images from this publication.See all images (4)Free text

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.

Publication Types, MeSH Terms, Substances, Secondary Source ID

Publication Types

MeSH Terms

Substances

Secondary Source ID

PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk