[Show abstract][Hide abstract] ABSTRACT: We cloned a plant gene, Ntcyc07, conferring arsenite tolerance by expressing a tobacco expression library in WT yeast (Y800). Expression of Ntcyc07 increased the tolerance to As(III) and decreased its accumulation, suggesting that the enhanced As(III) tolerance resulted from a reduction of the intracellular arsenic level. Interestingly, expression of Ntcyc07 increased the expression of the As(III) export carrier ACR3, but repressed that of As(III) uptake channel FPS1. Ntcyc07p interacted with Acr1p, which is the transcriptional activator of ACR3, but not with the ACR3 promoter. Taken together, the data indicated that Ntcyc07p promoted As(III) tolerance by decreasing the intracellular level of As(III) via increasing the expression of ACR3 and reducing that of FPS1.
[Show abstract][Hide abstract] ABSTRACT: MSN1 is a putative yeast transcriptional activator involved in chromium (Cr) accumulation. Here we show that overexpression of MSN1 enhances Cr and sulfur accumulation and Cr tolerance in transgenic tobacco. In addition, we found that expression of NtST1 (Nicotiana tabacum sulfate transporter 1) was elevated in MSN1- expressing transgenic tobacco, suggesting that chromate and sulfate are taken up via the sulfate transporter in plants. Supporting this, expression of NtST1 increased levels of Cr and S in Saccharomyces cerevisiae. Our findings suggest that yeast transcriptional activators can be used for developing effective metal remediators, and for improving the nutritional status of plants.