Thioredoxin reductase (TrxB) is a flavoprotein which acts as an integral part of Thioredoxin (Trx) system. This Trx system produces reducing equivalent in various oxidation-reduction reaction which ultimately targets in various metabolic processes inside cell. TrxB must be playing role in combating various stress conditions confronted by Salmonella Typhimurium (ST) inside its host. The aim was to clone and sequence Thioredoxin reductase (trxB) gene of ST strain E2375 and to construct a phylogenetic tree based on the information obtained after aligning the trxB sequence with other serovars of ST. Salmonella Typhimurium (ST) strain E2375 was procured from National Salmonella Centre, Indian Veterinary Research institute, Bareilly, India. Genomic DNA was isolated from the bacteria followed by amplification of Thioredoxin reductase(trxB) gene by PCR. The gene was restriction digested and cloned into a vector pET28c(+). The cloned trxB plasmid was transformed into NEB 5-alpha cells. The gene was sequenced and submitted in the gene bank. After multiple alignment analysis of that sequence by

BLAST, a phylogenetic tree was constructed with the help of MEGA4.0 software. The sequence of trxB was found to be highly

conserved among the salmonella serovars.