Molecular insight into the expression of metal transporter genes in Chryseobacterium sp. PMSZPI isolated from uranium deposit

Metal tolerant bacterium Chryseobacterium sp. PMSZPI previously isolated and characterized from uranium ore deposit was studied for elucidating the role of metal transporter genes belonging to the Cation Diffusion Facilitator (CDF), Root-Nodulation-Division (RND) and P-IB-type ATPase family in cadmium and uranium tolerance. The bacterium showed tolerance towards cadmium (MIC similar to 6mM) and uranium (MIC similar to 2mM) and was found to harbor metal transporter genes belonging to CDF, RND and P-IB-type ATPase family of proteins. Expression studies by real-time PCR showed an upregulation of czcA(RND), czcD(CDF) and cadA(P-IB-type ATPase) genes in presence of cadmium or uranium. Higher expression of czcA and czcD was found when the bacterium was treated with cadmium and uranium respectively. This study provides significant insight into the molecular mechanism that plays a role in cadmium and uranium tolerance in bacteria.