Broad-Spectrum Quorum Quenching and Biocontrol Potential of Pseudomonas procumbens sp. nov. and Pseudomonas polia sp. nov. via Degradation of Multiple Quorum Sensing Molecules

Bacterial plant diseases present a serious threat to global agriculture, underscoring the need for sustainable biocontrol solutions. Quorum quenching (QQ), which disrupts quorum sensing (QS) to reduce virulence without promoting resistance, offers a promising approach. This study established enrichment cultures with 3-hydroxy palmitic acid methyl ester (3-OH PAME) as the sole carbon source to isolate QQ bacteria against Ralstonia solanacearum. Two novel species, Pseudomonas procumbens sp. nov. (QE6) and P. polia sp. nov. (QL9), exhibited robust and broad-spectrum QQ activity against multiple QS signals, including 3-OH PAME, 3-hydroxy myristic acid methyl ester (3-OH MAME), diffusible signal factor (DSF), and N-acyl homoserine lactones (AHLs). Phylogenetic analysis placed both strains within the P. aeruginosa group and identified functional genes associated with DSF, AHL, and putative 3-OH PAME/MAME degradation, validated via gene deletion and heterologous expression. Both strains effectively controlled plant bacterial diseases mediated by these QS signals, highlighting their potential as eco-friendly, multifunctional QQ-based biocontrol agents.