Artificial induction of cadmium tolerance and its further enhancement via heterologous co-expression of SpHMT1 and AtPCS1 in the yeast cells
2014
Lee, S., Kyungpook National University, Daegu, Republic of Korea
Microorganisms can be used in the bioremediation of heavy metals. It is desirable if the microorganisms show a strong tolerance as well as the ability to accumulate (or biosorb) heavy metals. Yeast is well known for having a high capacity of biosorption of heavy metals. Therefore, the present study focused on developing a yeast mutant that has a strong tolerance to cadmium (Cd), a representative toxic metal. The Cd-resistant yeast mutant (CdR) was induced and isolated by growing yeast cells in media containing Cd and gradually increasing the concentration until reaching a possible maximum of 20 mM CdCl2, to which the cells adapted and survived. CdR cells showed stronger tolerance to Cd-induced stress than the control cells. To obtain even higher Cd tolerance in the yeast cells, both Schizosaccharomyces pombe heavy metal tolerance factor 1 (SpHMT1) and Arabidopsis thaliana phytochelatin synthase (AtPCS1) genes were introduced into the CdR cells to be expressed simultaneously. The transformed CdR cells showed higher Cd tolerance than the untransformed CdR cells.
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