Affiliations 

  • 1 School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China. Electronic address: xgliu66@yahoo.com
  • 2 School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China. Electronic address: wuyan@ujs.edu.cn
  • 3 Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China. Electronic address: 996336827@qq.com
  • 4 Institute of Life Sciences, Jiangsu University, Zhenjiang 212013, China. Electronic address: 347151488@qq.com
  • 5 School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK. Electronic address: Nigel.Halliday@nottingham.ac.uk
  • 6 Department of Plant Pathology, Shandong Agricultural University, Tai'an 271018, China. Electronic address: kexianggao@yahoo.com
  • 7 Division of Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia. Electronic address: kokgan@um.edu.my
  • 8 School of Life Sciences, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2RD, UK. Electronic address: miguel.camara@nottingham.ac.uk
Res. Microbiol., 2016 Apr;167(3):168-77.
PMID: 26671319 DOI: 10.1016/j.resmic.2015.11.003

Abstract

The σ(S) subunit RpoS of RNA polymerase functions as a master regulator of the general stress response in Escherichia coli and related bacteria. RpoS has been reported to modulate biocontrol properties in the rhizobacterium Serratia plymuthica IC1270. However, the role of RpoS in the stress response and biofilm formation in S. plymuthica remains largely unknown. Here we studied the role of RpoS from an endophytic S. plymuthica G3 in regulating these phenotypes. Mutational analysis demonstrated that RpoS positively regulates the global stress response to acid or alkaline stresses, oxidative stress, hyperosmolarity, heat shock and carbon starvation, in addition to proteolytic and chitinolytic activities. Interestingly, rpoS mutations resulted in significantly enhanced swimming motility, biofilm formation and production of the plant auxin indole-3-acetic acid (IAA), which may contribute to competitive colonization and environmental fitness for survival. These findings provide further insight into the strain-specific role of RpoS in the endophytic strain G3 of S. plymuthica, where it confers resistance to general stresses encountered within the plant environment. The heterogeneous functionality of RpoS in rhizosphere and endophytic S. plymuthica populations may provide a selective advantage for better adaptation to various physiological and environmental stresses.

* Title and MeSH Headings from MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.