Cloning and characterization of cobalt tolerance genes by metatranscriptomics approach

Abstract

Heavy metal contamination in soil is posing serious threat to environment. These are potentially toxic, depending on their bio available concentrations and sensitivity of the organism that is exposed. Metatranscriptomics is a recent culture-independent approach in microbial ecology which gives a direct and simultaneous access to the genes expressed by all the microbial species, cultivable or not, living in a common environment. In the present study, functional metatranscriptomics approach was adopted to identify cobalt tolerance genes expressed by eukaryotic species. Size fractionated libraries were constructed in the modified pFL61 yeast-E. coli shuttle vector. The fractionated library was screened for the presence of cobalt tolerance genes by functional complementation of Saccharomyces cerevisae mutant. The mutant strain, cobalt sensitive COT1 was used in this study. Yeast transformants exhibiting cobalt tolerance were identified by plating on medium supplemented with cobalt further characterized by studying their growth kinetics in the presence of cobalt.