Expression of tobacco cDNA encoding phytochelatin synthase promotes tolerance to and accumulation of Cd and As inSaccharomyces cerevisiae

The first tobacco cDNA encoding phytochelatin synthase (NtPCS1) has been cloned by complementing the YCF1 (vacuolar ABC type transporter)-depleting yeast mutant DTY167 with an expression library fromNicotiana tabacum. When NtPCSI was over-expressed in DTY165 (WT) and DTY167 (mutant), tolerance to and the accumulation of cadmium (Cd) were enhanced. Interestingly, its expression promoted these responses as well to arsenic (As), but only in DTY167. We conclude thatNtPCS1 plays a role in tolerance to and the accumulation of both toxic metals inSaccharomyces cerevisiae. These authors contributed equally to the work.