Identification and phylogenetic analysis of TEM gene from soil isolates

Abstract

This study presents isolation and identification of naturally occurring β-lactamase (BL) producing microorganisms from soil samples of the Western Ghats of Kerala, India. Soil samples were plated on ampicillin supplemented nutrient agar. Genomic DNA was amplified using a degenerate primer pair designed based on TEM gene sequence alignment. Full-length BL encoding gene was amplified using blaTEM specific primer. PCR product was identified by sequencing and blast analysis as a blaTEM encoding ORF. The deduced protein sequence showed 99% homology with TEM 116 gene reported from Uruguay, South Korea and Taiwan. Phylogenic study of TEM family using DNA and protein sequences showed clustering of sequences along with TEM 116 forming a separate cluster. The clustering of TEM 116 along with three isolates showed that these isolates might have evolved from a common ancestor. Alignment of soil isolates along with TEM 116 showed that under natural conditions also mutations occurred and TEM gene was present in soil isolates.