Cloning, Sequencing and Phylogenetic Analysis of Stn Gene of Salmonella Typhimurium

Yashpal Singh¹, Apoorv Tiwari^1, Rajesh Kumar² and M. K. Saxena³

¹Department of Molecular Biology and Genetic Engineering, G.B. Pant University of Agriculture and Technology,Pantnagar 263145, India.

²Department of Veterinary Microbiology, G.B. Pant University of Agriculture and Technology, India.

³Animal Biotechnology Center, Department of Veterinary Physiology and Biochemistry, G.B. Pant University of Agriculture and Technology, Pantnagar 263145, India.

Corresponding Author E-mail mumtesh@rediffmail.com

DOI : http://dx.doi.org/10.13005/bbra/2583

ABSTRACT: Salmonella Typhimurium is an important  pathogen having broad host range . Several genes contribute in virulence of Salmonella. Stn is an important virulent gene which code for Salmonellatoxin, increases the level of c-AMP in the host, and ultimately results into diarrhoea and vomiting. In present study stn gene was cloned, sequenced and on basis of sequence information of stn gene,phylogenetic relation was deduced between different serovars of Salmonella Typhimurium. Genomic DNA was isolated from field isolate of Salmonella Typhimurium (isolate No-A201) and stn gene was amplified using gene specific primer and cloned in pJET vector by the positive selection system. Amplification of stn gene yielded a product of approximately 750 bp.  Subsequently gene was sequenced and a complete ORF of 750 bp was obtained. The sequence was submitted to NCBI Genbank and allotted the Accession No KF032246 was allocated.Sequence was further used for bioinformatics analysis of Stnprotein, which exhibited two major domains and one amino acid substitution at 609residue. On phylogenetic analysis, S.Typhimurium exhibited 99% similarity with Salmonella enterica subsp. entericaserovar Newport.Our findings indicate that stn is an important toxin gene, which is conserved among many serovars of Salmonella. Therefore, it may be proven as a suitable candidate for development of sub-unit vaccine against Salmonella.

KEYWORDS: Gene; Protein; Salmonella; Vaccine

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