Potential of plant chloroplast-based recombinant expression systems to express bacterial membrane proteins as vaccine candidates for Salmonella in poultry

Abstract Zoonotic diseases pose significant public health risks, with Salmonella being a major pathogen responsible for gastroenteritis, often transmitted through contaminated poultry products. Effective control of Salmonella in poultry is critical, but current methods face limitations due to the stealthy nature of the bacteria, which can persist in asymptomatic birds and spread during slaughter and processing. In this study, we investigated the potential of Nicotiana tabacum chloroplasts to produce TonB-dependent outer membrane transporters (TBDTs), including CirA, FepA, FhuA and IroN from Salmonella Enteritidis. These membrane proteins are critical for bacterial iron uptake and represent promising vaccine targets. Transplastomic tobacco plants successfully produced full-length recombinant CirA, FepA, and IroN proteins. Immunization of mice with chloroplast extracts containing these proteins elicited significant antibody responses, with statistical significance observed for CirA and FepA ( p < 0.05). Fluorescence microscopy demonstrated specific antibody binding to Salmonella cells, confirming immune recognition. These findings highlight the feasibility of using chloroplasts to produce complex bacterial membrane proteins and support the development of plant-based vaccines targeting iron acquisition systems to combat Salmonella infections in poultry.