Comparative Genomic and Metabolomic Analyses of TwoPseudomonas aeruginosaStrains With Different Antifungal Activities

Pseudomonas aeruginosaisolated from the plant rhizosphere has been widely used as an effective strain in biological control against plant disease. This bacterium promotes plant growth and protect plants against various phytopathogens through the production of phenazine metabolites. In this study, the strainP. aeruginosaY12 with anti-Beauveria bassianaactivity was isolated from the gut of housefly larvae. It was comparatively analyzed with the strainP. aeruginosaP18, which showed no anti-B. bassianaactivity. Genomic and metabolomic methods were used to obtain a comprehensive understanding of the antimicrobial mechanism of Y12. After whole-genome resequencing of the two strains, a total of 7,087 non-synonymous single-nucleotide polymorphisms (nsSNPs), 1079 insertions and deletions (InDels), 62 copy-number variations (CNVs) and 42 structural variations (SV) were found in both strains. We analyzed the differentially abundant metabolites between Y12 and P18, and identified six bioactive compounds that could be associated with the antimicrobial activity of Y12. Additionally, we found that, unlike other previously reported rhizosphericP. aeruginosastrains, Y12 could produce both phenazine-1,6-dicarboxylic acid (PDC) and pyocyanin (PYO) at significantly higher concentrations than P18. AsB. bassianais an effective biological insecticide that can cause high mortality in adult houseflies but has little effect on housefly larvae, we believe thatP. aeruginosaY12, identified in housefly larvae but not in adults, were beneficial for the development of housefly larvae and could protect them fromB. bassianainfection through the production of toxic metabolites.