Current Microbiology

, Volume 52, Issue 5, pp 333–339

A Proteomic Approach Towards the Analysis of Salt Tolerance in Rhizobium etli and Sinorhizobium meliloti Strains

  • Abdelaal Shamseldin
  • Julius Nyalwidhe
  • Dietrich Werner

DOI: 10.1007/s00284-005-6472-7

Cite this article as:
Shamseldin, A., Nyalwidhe, J. & Werner, D. Curr Microbiol (2006) 52: 333. doi:10.1007/s00284-005-6472-7


Soluble proteins from the salt-tolerant Rhizobium etli strain EBRI 26 were separated by two-dimensional (2D) gel electrophoresis and visualised by Commassie staining. Six proteins are highly expressed after induction by 4% NaCl compared to the non-salt-stressed cells. These proteins have pI between 5 and 5.5 and masses of approximately 22, 25, 40, 65, 70, and 95 kDa. These proteins were analysed by Matrix-assisted laser adsorption ionization time of flight (MALDI-TOF) after digestion with trypsin. Despite having very good peptide mass fingerprint data, these proteins could not be identified, because the genome sequence of R. etli is not yet published. In a second approach, soluble proteins from salt-induced or non-salt-induced cultures from R. etli strain EBRI 26 were separately labelled with different fluorescent cyano-dyes prior to 2D difference in gel electrophoresis. Results revealed that 49 proteins are differentially expressed after the addition of sodium chloride. Fourteen proteins are overexpressed and 35 were downregulated. The genome of Sinorhizobium meliloti, a closely related species to R. etli, has been published. Similar experiments using Sinorhizobium meliloti strain 2011 identified four overexpressed and six downregulated proteins. Among the overexpressed protein is a carboxynospermidin decarboxylase, which plays an important role in the biosynthesis of spermidin (polyamine). The enzyme catalase is among the downregulated proteins. These proteins may play a role in salt tolerance.

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • Abdelaal Shamseldin
    • 1
  • Julius Nyalwidhe
    • 3
  • Dietrich Werner
    • 2
  1. 1.Environmental Biotechnology Department, Genetic Engineering and Biotechnology Research InstituteMubarak City for Scientific Research and Technological ApplicationsNew Borg El-ArabEgypt
  2. 2.Fachbereich Biologie, Fachgebiet Zellbiologie und Angewandte BotanikPhilipps-Universität MarburgMarburgGermany
  3. 3.Fachbereich Biologie, Abteilung ParasitologiePhilipps-Universität MarburgMarburgGermany

Personalised recommendations