Open AccessPseudomonas aeruginosa glutathione biosynthesis genes play multiple roles in stress protection, bacterial virulence and biofilm formation
Author(s) -
Lampet Wongsaroj,
Kritsakorn Saninjuk,
Adisak Romsang,
Jintana Duang-nkern,
Wachareeporn Trinachartvanit,
Paiboon Vattanaviboon,
Skorn Mongkolsuk
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0205815
Subject(s) - virulence , pyocyanin , pseudomonas aeruginosa , biofilm , mutant , microbiology and biotechnology , glutathione , complementation , biology , methylglyoxal , swarming motility , pyoverdine , biochemistry , gene , chemistry , quorum sensing , bacteria , genetics , enzyme
Pseudomonas aeruginosa PAO1 contains gshA and gshB genes, which encode enzymes involved in glutathione (GSH) biosynthesis. Challenging P . aeruginosa with hydrogen peroxide, cumene hydroperoxide, and t -butyl hydroperoxide increased the expression of gshA and gshB . The physiological roles of these genes in P . aeruginosa oxidative stress, bacterial virulence, and biofilm formation were examined using P . aeruginosa Δ gshA , Δ gshB , and double Δ gshA Δ gshB mutant strains. These mutants exhibited significantly increased susceptibility to methyl viologen, thiol-depleting agent, and methylglyoxal compared to PAO1. Expression of functional gshA , gshB or exogenous supplementation with GSH complemented these phenotypes, which indicates that the observed mutant phenotypes arose from their inability to produce GSH. Virulence assays using a Drosophila melanogaster model revealed that the Δ gshA , Δ gshB and double Δ gshA Δ gshB mutants exhibited attenuated virulence phenotypes. An analysis of virulence factors, including pyocyanin, pyoverdine, and cell motility (swimming and twitching), showed that these levels were reduced in these gsh mutants compared to PAO1. In contrast, biofilm formation increased in mutants. These data indicate that the GSH product and the genes responsible for GSH synthesis play multiple crucial roles in oxidative stress protection, bacterial virulence and biofilm formation in P . aeruginosa .