Cyc07 enhances arsenite tolerance by reducing As levels in Nicotiana tabacum and Arabidopsis thaliana

Arsenic is a major pollutant that contaminates land, water, and air. We previously reported that the expression of tobacco Ntcyc07 confers arsenite (As III) tolerance by decreasing the arsenic level by promoting the transcription of the arsenite export carrier ACR3 and inhibiting that of the As(III) uptake transporter FPS1 in S. cerevisiae (Mok et al. 2008). To examine if Ntcyc07 is also involved in As(III) tolerance and accumulation in plants, we generated transgenic tobacco and Arabidopsis that overexpress Ntcyc07. The Ntcyc07 tobacco exhibited increased tolerance to but decreased accumulation of arsenite, but the Ntcyc07 Arabidopsis showed enhanced As(III) tolerance and no change in the As level. In contrast, Atcyc07 knockout Arabidopsis (Atcyc07 is a homolog of Ntcyc07) displayed reduced As(III) tolerance and an increased As level. Taken together, cyc07 promotes As(III) tolerance by decreasing the cellular accumulation of arsenite in plants.