AUTHOR=Lei Lei , Chen Jiahui , Liao Weifang , Liu Pulin 

TITLE=Determining the Different Mechanisms Used by Pseudomonas Species to Cope With Minimal Inhibitory Concentrations of Zinc via Comparative Transcriptomic Analyses

JOURNAL=Frontiers in Microbiology

VOLUME=11

YEAR=2020

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2020.573857

DOI=10.3389/fmicb.2020.573857

ISSN=1664-302X

ABSTRACT=<p><italic>Pseudomonas</italic> is one of the most diverse bacterial genera identified in the environment. Genome sequence analysis has indicated that this genus can be clustered into three lineages and ten groups. Each group can adopt different mechanisms to thrive under zinc-depleted or high-zinc conditions, two environments that are frequently encountered during their environmental propagation. The response of three prominent <italic>Pseudomonas</italic> strains (<italic>Pseudomonas aeruginosa</italic> PAO1, <italic>Pseudomonas putida</italic> KT2440, and <italic>Pseudomonas fluorescens</italic> ATCC 13525<sup>T</sup>) to minimal inhibitory concentrations of zinc were compared using RNA-seq and ultra-performance liquid chromatography–tandem mass spectrometry analysis. Results demonstrated that the three strains shared only minimal similarity at the transcriptional level. Only four genes responsible for zinc efflux were commonly upregulated. <italic>P. aeruginosa</italic> PAO1 specifically downregulated the operons involved in siderophore synthesis and the genes that encode ribosomal protein, while upregulated the genes associated with antibiotic efflux and cell envelope biosynthesis. The membrane transporters in <italic>P. putida</italic> KT2440 were globally downregulated, indicating changes in cell permeability. Compared with <italic>P. aeruginosa</italic> PAO1 and <italic>P. putida</italic> KT2440, the most remarkable transcriptional variation in <italic>P. fluorescens</italic> ATCC 13525<sup>T</sup> is the significant downregulation of the type VI secretion system. Metabolite quantitative analysis showed that low concentrations of the metabolites involved in central carbon metabolism and amino acid synthesis were detected in the three strains. In summary, the cellular responses of the three strains under high-zinc condition is quite divergent. Although similar metal efflux systems were upregulated, the three strains employed different pathways to reduce zinc intrusion. In addition, zinc treatment can increase the difficulties of scavenging <italic>P. aeruginosa</italic> from its colonization area, and reduce the competitiveness of <italic>P. fluorescens</italic> in microbiota.</p>