The response of Pyropia haitanensis to Inorganic Arsenic under Laboratory Culture

P. haitanensis was treated with inorganic arsenic pentavalent arsenic and trivalent arsenicals at different concentrations for three day. The results indicated that P. haitanensis reduce the uptake of inorganic arsenic or increase vacuolar compartmentalization of trivalent arsenicals via regulating the expression of related transporters, and bring down the negative effect of inorganic arsenics through up-regulating or down-regulating the expression of genes involved in affected biochemical pathways. In addition, P. haitanensis can quickly transform them into organoarsenicals, the mainly arsenosugars when being incubated with pentavalent arsenic and low concentrations of trivalent arsenicals. Trivalent arsenicals were readily accumulated by alga and its toxicity to P. haitanensis is far more than pentavalent arsenic. However, it has not evolved appropriate mechanism to detoxify high concentrations of trivalent arsenicals likely because pentavalent arsenic is the main arsenic form in its inhabitant environment. Our study uncovered the response and transformation of P. haitanensis to inorganic arsenic under laboratory culture condition, and provided novel insights into arsenic transformation in marine alga.