Pteris vittata is the most well-known arsenic (As) hyperaccumulator, while the corresponding mechanism in molecular level is still not clear. In this study, As uptake and transport in P. vittata were demonstrated by time-course analyses under As addition. Then expression of 3 genes (PvPht1;3, a phosphate (P) transporter gene; PvACR2, a AsV reductase gene; PvACR3, a AsIII transport gene) was focused on to examine their contributions on As processing in root of P. vittata. Results of As addition analyses revealed that P. vittata had high-sensitivity to even 10 ppb AsV which was quickly depleted within 6 h, while this high affinity was inhibited when coexisting with P. Analyses to As in the plant showed that in the absence of P, 99 % of the As taken up by roots was reduced to AsIII at 7 d. And 85 % of As transported to rhizomes was present as AsIII, 74 % of the As accumulated in fronds was AsIII. Results of qRT-PCR demonstrated that the transcription of PvPht1;3 was temporally induced by 100 ppb AsV without P, while 500 ppb of AsV made this induction kept through the entire period which showed 3.7-fold higher than control at 7 d. Meanwhile, PvACR2 was only induced slightly (1.15–1.45-fold) by 500 ppb AsV with a time lag, and this induction wasn't infected by P. PvACR3 was induced by 100 ppb AsV immediately, and the strength was positively related to AsV concentration. Intriguingly, the expression of PvACR3 fitted the AsIII concentration in the root. Our results suggested a collaboration of these three genes in sensitive AsV absorption, constitutive AsV reduction and subsequent AsIII transportation which contributes to As hyperaccumulation by P. vittata.
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