Expression of stress responsive genes enables to cross-protection against acid, bile salt, and freeze-drying.

Introduction: effectively colonizing the gut, secretes antimicrobial compounds and strengthens immune system function. Considering these health benefits, increasing its stress assessments efficiency could improve its commercial viability.

Methods: In this work, the resistance of FP41 to acid, bile salts, and freeze-drying was examined.

Results: The findings showed that strain FP41 demonstrated a strong resistance to acid/bile salt stresses. The transcriptome revealed a significant up-regulation of various stress response genes, including those related to membrane integrity, glutamine metabolism, OsmC family protein, ABC transporters, and chaperonin. Subsequent research demonstrated that overexpression of three stress response-specific proteins, including glutamate decarboxylase GatD, osmotically induced bacterial protein OsmC, and membrane protein component CsbD, significantly increased the survival rate of Z204 under acid/bile salts stress. Notably, overexpression of the OsmC, CsbD, and GatD proteins also enhanced the survival of after freeze-drying.

Discussion: The development of a unique cross-protection method is highlighted in this study, that might significantly increase cellular resistance to acid, bile salts, and cold stresses. This finding could significantly impact the way that is employed in industrial manufacturing processes.