RRC ID 21720
Author Harke MJ, Berry DL, Ammerman JW, Gobler CJ.
Title Molecular response of the bloom-forming cyanobacterium, Microcystis aeruginosa, to phosphorus limitation.
Journal Microb. Ecol.
Abstract Cyanobacteria blooms caused by species such as Microcystis have become commonplace in many freshwater ecosystems. Although phosphorus (P) typically limits the growth of freshwater phytoplankton populations, little is known regarding the molecular response of Microcystis to variation in P concentrations and sources. For this study, we examined genes involved in P acquisition in Microcystis including two high-affinity phosphate-binding proteins (pstS and sphX) and a putative alkaline phosphatase (phoX). Sequence analyses among ten clones of Microcystis aeruginosa and one clone of Microcystis wesenbergii indicates that these genes are present and conserved within the species, but perhaps not the genus, as phoX was not identified in M. wesenbergii. Experiments with clones of M. aeruginosa indicated that expression of these three genes was strongly upregulated (50- to 400-fold) under low inorganic P conditions and that the expression of phoX was correlated with alkaline phosphatase activity (p < 0.005). In contrast, cultures grown exclusively on high levels of organic phosphorus sources (adenosine 5'-monophosphate, β-glycerol phosphate, and D: -glucose-6-phosphate) or under nitrogen-limited conditions displayed neither high levels of gene expression nor alkaline phosphatase activity. Since Microcystis dominates phytoplankton assemblages in summer when levels of inorganic P (P(i)) are often low and/or dominate lakes with low P(i) and high organic P, our findings suggest this cyanobacterium may rely on pstS, sphX, and phoX to efficiently transport P(i) and exploit organic sources of P to form blooms.
Volume 63(1)
Pages 188-98
Published 2012-1
DOI 10.1007/s00248-011-9894-8
PMID 21720829
MeSH Alkaline Phosphatase / biosynthesis Alkaline Phosphatase / metabolism Bacterial Proteins / genetics Base Sequence Biological Transport, Active / genetics Genes, Bacterial Microcystis / genetics* Microcystis / growth & development Microcystis / metabolism* Phosphate-Binding Proteins / genetics* Phosphorus / metabolism* Phytoplankton / growth & development Sequence Alignment Sequence Analysis, DNA
IF 3.611
Times Cited 63
Algae NIES-843