Functional Genomics of Stress Response in Pseudomonas putida KT2440

Abstract

The metabolically versatile soil bacterium Pseudomonas putida has to cope with numerous abiotic stresses in its habitats. The stress responses of P. putida KT2440 to 4°C, pH 4.5, 0.8 M urea, and 45 mM sodium benzoate were analyzed by determining the global mRNA expression profiles and screening for stress-intolerant nonauxotrophic Tn5 transposon mutants. In 392 regulated genes or operons, 36 gene regions were differentially expressed by more than 2.5-fold, and 32 genes in 23 operons were found to be indispensable for growth during exposure to one of the abiotic stresses. The transcriptomes of the responses to urea, benzoate, and 4°C correlated positively with each other but negatively with the transcriptome of the mineral acid response. The CbrAB sensor kinase, the cysteine synthase CysM, PcnB and VacB, which control mRNA stability, and BipA, which exerts transcript-specific translational control, were essential to cope with cold stress. The cyo operon was required to cope with acid stress. A functional PhoP, PtsP, RelA/SpoT modulon, and adhesion protein LapA were necessary for growth in the presence of urea, and the outer membrane proteins OmlA and FepA and the phosphate transporter PstBACS were indispensable for growth in the presence of benzoate. A lipid A acyltransferase (PP0063) was a mandatory component of the stress responses to cold, mineral acid, and benzoate. Adaptation of the membrane barrier, uptake of phosphate, maintenance of the intracellular pH and redox status, and translational control of metabolism are key mechanisms of the response of P. putida to abiotic stresses.

Identification of opsA , a Gene Involved in Solute Stress Mitigation and Survival in Soil, in the Polycyclic Aromatic Hydrocarbon-Degrading Bacterium Novosphingobium sp. Strain LH128

“…Moreover, the C-terminal domains have been suggested to be anchored with peptidoglycan in both Gram-positive and Gram-negative bacteria (53). The growth of mutant NA7E1 was impaired not only in the presence of NaCl but also in the presence of other ionic solutes (from about 200 mM) and sucrose at 400 mM, while it was not affected by PEG 6000, which, rather, reduced water activity by macromolecule-water interactions (59,60). These observations suggest that OpsA in strain LH128 is important for alleviating not only NaCl stress but also stress from other solutes.…”

Genomic Analysis of the Role of RNase R in the Turnover of Pseudomonas putida mRNAs

“…Inactivation of the P. putida KT2440 rnr gene impairs growth at 4°C, but not at 30°C (32). Growth at other temperatures was not reported.…”

Global Regulation of Food Supply by P seudomonas p utida DOT-T1E

“…In natural environments, catabolite repression is likely of great importance in the success of bacteria when they compete for available nutrients with other microorganisms (15). Bacteria are able to adapt to changes in their environment via numerous signaling pathways, and this adaptation commonly involves the alteration of metabolic gene expression in order to meet the current growth requirements (46). Global regulatory genes are frequently involved in this decision-making process as they allow for substrate-specific responses and direct regulation of the metabolic pathway in question.…”