Use of proteomic tools to analyze genes involved in thermal- and alkaline-tolerance Rhizobium strains nodulating Egyptian clover

Abdelaal Shamseldin, Wafaa M. Abd El-Rahim, Hassan Moawad, Michael J. Sadowsky

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Environmental stresses such as salinity, alkalinity and high temperature are main factors that restrict or limit symbiotic nitrogen fixation with legumes. Three of 48 Rhizobium strains that were isolated from root nodules of Egyptian winter clover displayed tolerance to different harsh environmental conditions that could prove helpful for the development of new and effective inoculants for this legume crop. Rhizobium strain Rhiz1017 was selected to analyze proteins that affect its survival under elevated temperature (42°C) or alkaline conditions pH9. Both of 2D-DIGE and MALDI-TOF-TOF analyses indicated that changes of up- or down-regulated proteins under alkaline conditions (pH9) were less affected than temperature stress. Analysis of 1,792 protein spots under temperature stress indicated that strain Rhiz 1017 are up-regulated proteins responsible for the biosynthesis of organic solutes such as glycine, betaine, ectoine and mannitol, and polyamine (putrascine,) and energy generation. In addition, while the expression of chaperonin GroEl was enhanced, proteins responsible for storing energy such as poly beta hydroxyl butyrate were down regulated. At pH 9, beta keto-thiolase was significantly up regulated protein. Our results give insights into potential mechanism by which rhizobia respond to thermal and alkaline conditions; this knowledge will be useful in developing improved legume-microbe symbiosis to increase the productivity of legume crops in Egyptian dry ecosystems.

Original languageEnglish (US)
Pages (from-to)2994-3004
Number of pages11
JournalResearch Journal of Pharmaceutical, Biological and Chemical Sciences
Issue number5
StatePublished - Sep 1 2016

Bibliographical note

Funding Information:
This work was funded, in part, through the Science and Technology Development Fund (STDF) of Egypt, under project ID 1268. Special thanks to Dave Westenberg and Nyalwidhe Julius for initial reading of the manuscript, and thanks to John Ferguson for his computer skills.

Copyright 2018 Elsevier B.V., All rights reserved.


  • Egyptians soils
  • Proteomic analysis
  • Rhizobium strains
  • Thermal- and alkaline tolerance


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