Applied Microbiology and Biotechnology

, Volume 97, Issue 24, pp 10499–10509

Alteration of the exopolysaccharide production and the transcriptional profile of free-living Frankia strain CcI3 under nitrogen-fixing conditions

  • Hae-In Lee
  • Andrew J. Donati
  • Dittmar Hahn
  • Louis S. Tisa
  • Woo-Suk Chang
Applied microbial and cell physiology

DOI: 10.1007/s00253-013-5277-z

Cite this article as:
Lee, HI., Donati, A.J., Hahn, D. et al. Appl Microbiol Biotechnol (2013) 97: 10499. doi:10.1007/s00253-013-5277-z

Abstract

We investigated the effect of different nitrogen (N) sources on exopolysaccharide (EPS) production and composition by Frankia strain CcI3, a N2-fixing actinomycete that forms root nodules with Casuarina species. Frankia cells grown in the absence of NH4Cl (i.e., under N2-fixing conditions) produced 1.7-fold more EPS, with lower galactose (45.1 vs. 54.7 mol%) and higher mannose (17.3 vs. 9.7 mol%) contents than those grown in the presence of NH4Cl as a combined N-source. In the absence of the combined N-source, terminally linked and branched residue contents were nearly twice as high with 32.8 vs. 15.1 mol% and 15.1 vs. 8.7 mol%, respectively, than in its presence, while the content of linearly linked residues was lower with 52.1 mol% compared to 76.2 mol%. To find out clues for the altered EPS production at the transcriptional level, we performed whole-gene expression profiling using quantitative reverse transcription PCR and microarray technology. The transcription profiles of Frankia strain CcI3 grown in the absence of NH4Cl revealed up to 2 orders of magnitude higher transcription of nitrogen fixation-related genes compared to those of CcI3 cells grown in the presence of NH4Cl. Unexpectedly, microarray data did not provide evidence for transcriptional regulation as a mechanism for differences in EPS production. These findings indicate effects of nitrogen fixation on the production and composition of EPS in Frankia strain CcI3 and suggest posttranscriptional regulation of enhanced EPS production in the absence of the combined N-source.

Keywords

Exopolysaccharide (EPS) Frankia Symbiotic nitrogen fixation Nitrogen limitation Microarray qRT-PCR 

Supplementary material

253_2013_5277_MOESM1_ESM.pdf (195 kb)
ESM 1(PDF 194 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Hae-In Lee
    • 1
  • Andrew J. Donati
    • 1
  • Dittmar Hahn
    • 2
  • Louis S. Tisa
    • 3
  • Woo-Suk Chang
    • 1
  1. 1.Department of BiologyUniversity of TexasArlingtonUSA
  2. 2.Department of BiologyTexas State UniversitySan MarcosUSA
  3. 3.Department of Molecular, Cellular, and Biomedical SciencesUniversity of New HampshireDurhamUSA

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