Open AccessThe limits to genomic predictions: role of σ N in environmental stress survival of Pseudomonas putida
Author(s) -
Cases Ildefonso,
Lorenzo Vı́ctor
Publication year - 2001
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2001.tb00806.x
Subject(s) - pseudomonas putida , biology , sigma factor , mutant , rpon , sigma , microbiology and biotechnology , genetics , bacteria , gene , rna , gene expression , physics , promoter , quantum mechanics , rna polymerase
Based on genomic data and on the phenotypes of an FlhF mutant of Pseudomonas putida , the alternative sigma factor σ N (σ 54 ) has been proposed to play a key role in survival to various nutritional and environmental stresses in this bacterium. Quite in contrast, we show that unlike σ S (σ 38 ) the loss of σ N does not impair to any significant extent the ability of P. putida to survive long‐term starvation. rpoN mutants (lacking σ N ) are indistinguishable from the wild‐type with respect to solvent tolerance, resistance to heat shock or sensitivity to hydrogen peroxide. These data suggest that while σ N is a key component of expression of alternative biodegradative pathways for unusual carbon sources (i.e. m ‐xylene or dimethylphenols), its loss does not compromise bacterial endurance to gross types of environmental stress. Moreover, these results point out the limitations, if not the deception, of genomic predictions when confronted with experimental data.