Regulatory and antimicrobial dual functions of the pvf cluster in biocontrol strain Pseudomonas sp. MUP55

Bacterial antimicrobial compounds and global regulatory networks are typically studied as separate systems, limiting our understanding of how these functions might be integrated. Here we reveal a dual-function system in the biocontrol strain Pseudomonas sp. MUP55, where the pvf cluster simultaneously functions as a global regulator of specialized metabolism and produces direct antimicrobial compounds. Metabolomic and transcriptomic analysis of a ∆pvfC mutant showed extensive global change of the regulation of metabolites and gene expression, with effects on specialized metabolites. Remarkably, pvfC differentially regulates dual siderophore systems and uncouples typically co-regulated small regulatory RNAs in the Gac/Rsm cascade. Heterologous expression confirmed the pvf cluster produces compounds with direct antimicrobial activity independent of its regulatory functions. Comparative genomic analysis revealed the MUP55 pvf cluster contains a rare additional pvfE gene found in only 3.4% of identified pvf clusters. This evolutionary integration of regulatory and defensive functions within a single genetic system provides an efficient strategy for bacterial competitive fitness and resource allocation, expanding our understanding of how beneficial microbes coordinate cellular processes while maintaining environmental competitiveness RNA-seq for the WT and the pvfC mutant.